2: Heat Pump – Coleman Mach 6535a-871

UPDATE: June 2023 Old Coleman Mach Model  6535-671 to be Replaced with 46515-611

Two three weeks ago, I had the AC running and suddenly it just died. Messed around with it too much I’m afraid as the CB popped while I was trying to get it running. That’s not good. Anyway, I found that the condenser fan, the big ‘Outside’ fan as Coleman calls it wasn’t running. Bad bushings. Pulled the motor, had it looked at a motor shop and found it had melted windings too. So, considered pulling that old unit and replacing with mini-splits which are all the rage these days. Here’s the rest of the story:

I considered all options with mini-splits, looked at the designs and installation instructions, measured the space in the basement and in the house where the evaporators would most reasonably be mounted and decided I’m just not up to converting to the mini-splits. I’ve considered it all, including the age of the Coleman unit and the many many hours I’ve put on the Coleman full timing since I bought the RV in 2016 so it’s gotten lots of use, and it just seems unlikely that I’d be able to fix it myself without some other failure cropping up after another hundred hours or so, so I decided that replacement made more sense then repair. If I only used the RV 2 months out of the year, yeah, repair would have made more sense but I use it 12 months of the year. Heating and cooling for weeks on end. And as a full timer, I don’t have a garage to work in. Just this cement parking pad. Lucky this RV park allows me to work on things.

Much as I’d like to, I’m currently not in an area where it’s cool enough to work on the mini-split project for a couple three weeks installing (in my current physical state, I’d need to spread it out). It’s too hot here already to work much of the day. And the sun is getting to be brutal shining on the heat pump side of the RV several hours each day even now.

So, all things considered, instead I went ahead and ordered a brand new improved Coleman 2-ton with Coleman 46515-611 as the model number. My unit was/is a Coleman 6535-671. It’s a redesign in the same package as my old one but is supposed to be more efficient. We’ll see. But efficiency doesn’t matter much as I was able to successfully use the 2002 Coleman for years without much trouble with parks electric  so improved efficiency is just icing on the cake. In reading the specs though, I’m not sure if that isn’t just marketing speak, not really an efficiency improvement that I can see.

It’s a lot of money, $3982 with free shipping, (from Hebron RV Parts) but installing it would only take a few hours, it’s designed for the existing space and still utilizes the duct work, thermostat, and wiring so there will be no ugly evaporators (evaps) hanging in awkward places inside my RV. I only have a 36 footer so mine isn’t as roomy as those 46 footers I’ve seen that have converted.

I did consider mounting the mini-splits evap in the space where the old tube TV hung over the dash, but even there it’s a problem as the evaps I’d get for a 13,500 BTU mini-split are wider than the opening for that space. If I’d opted for that installation than I was going to use the existing duct work to run the copper tubing and power to the front of the RV. In the rear, I was going to attempt to mount the 2nd evap on the ceiling a little forward of the bedroom cabinet’s doors. The cabinets just above the bed. Those are well made cabinets I have on the back wall of the bedroom (I have a n-s bed and I sleep with my head at the south end) and I’d hate to rip them out to gain mounting space, again attempting to run the copper tubing and electrical up to the evap through the venting. Problem there is accessing the duct work to thread the pipe and electric…would likely have to remove the end cap off the RV for access.

So yeah, I had ideas for installation of two 13.5K BTU mini-splits, equal to the 26,000 BTU Coleman and I would expect my installation would have looked fairly polished but I shelved it because we’re heading into summer and I just don’t have the time or cool enough weather. Plus it is NOT an uncomplicated job, I’m not all that physically fit, and with inevitable unintended consequences making for difficult job. It’s already in the 90’s here for several hours of the day. If it was at the end of summer, heading into our long fall with cool, comfortable working condition weather, I might have attempted it.

Thanks to everyone for the advice on iRV2 dot com, but I took the lazy (but expensive) route. If I still have this RV in 5 years, my cost will have been $67/mo. for a new heat pump. Added to the already steep cost of owning any RV. Yikes. Oh, well, I’ll just consider it to be a charge for RV park electric since I don’t often pay that directly when at the RV parks I visit.

AC Hack while waiting for the new Coleman Heat pump…click link…

Miscellaneous Heating & Cooling…

Here’s the link to the installation of the new heat pump in June of 2023.

3: Heat Pump – New Installed June 2023

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Coleman Maintenance: March 2019

Just started working on this issue as of March ’19. I’ve read that it takes a shop 3 to 6 hours to do typical servicing and the parts can run up to $600. And that’s just for general maintenance. If you need a compressor…ouch, over $2,000. Some owners just opt to buy a new unit for ~$2600 + $450 labor. I wanted to try to fix it myself because I like doing that sort of thing and when it was working, it’s quiet and really makes the RV comfortable in both cold or hot weather. When working outside, if it was running I’d often carefully listen to it because I was aware from my reading that they have a host of problems with bushings squealing and squirrel cage hubs breaking and I wanted to be ahead of the curve if it started making the noises I’d read about. Then came the day when I thought I heard a slight rattling from the pump. That progressively got louder over several months and then I started to hear a squealing. And that quickly became loud. Loud enough that there were sensitive neighbors that complained. I found I could lessen the noise if I switched shore power from 50 amp to 30 amp. Probably because only one compressor would run. So that gave me a couple weeks where I could use the A/C and not get complaints about the noise. I was camping in the SW at the time and it was early spring (late March) and getting hot in Yuma where I was staying so I headed back up to my membership park, Preferred RV in Pahrump to take advantage of cooler weather there while I worked on getting things back to normal operation in the pump.

First thing I did was read Duner’s excellent write up about his Mach heat pump removal, he’s an iRV2.com member and posted there but he has passed on and the old link to his RV site seems to be missing now. (July ’24 is when I discovered his passing). I mention him because there are still several iRV2.com posts of his with helpful info about the basement heatpumps. Just search iRV2.com.

After getting situated at the RV park, picked up 2 pieces of 2 X 6 from Home Depot (1 X 12″) at 4′ long and a couple plastic 5 gallon pails from the local flea market to make a bench to set the pump on for when it was out of the basement compartment rack.

The heat pump door is screwed in place…two screws on each side at the bottom of the grill in my RV. Access for the front set is with battery compartment door open, and there’s two screws screwed into the metal frame from underneath, on the left. After the screws are out, the door swings up and out of the way on hinges. I bungee corded it out of the way.

I quickly discovered that there’s no way on earth to reach the screws that hold on the 90 degree vent coupling that exits down low on the left side of the heat pump as recommended by Duner until I removed the RV’s lower rear fiberglass/plastic fender. That section of fiberglass wraps around the entire back of the RV. When the RV is manufactured, the fender is held on with a few screws on either side, and then they slap a big puddle of epoxy to the back of the fender that match up where the brackets attached to the frame are. Then they push the fiberglass fender up onto the brackets and the epoxy squeezes out of the brackets screw holes. After the epoxy dries, that is suppose to keep much of the fender attached. But after a few years, road vibration has caused most of the ‘epoxy screws’ to have broken off so the brackets come loose and the fender, like in my case, came loose except for the screws on the edges, and the two screws I’d added to hold it two years ago. That wobbling doesn’t do the fender any good so I’d added a couple screws back in ’17. During this job I added a couple more so it’s nice and firm now. See this page for links to that work…Body Work

I only had to remove several screws on either side, the two screws I’d added, and it comes right off. I’m not all that disappointed with all those epoxied on brackets letting loose because that protects that valuable piece of wrap around fender. It would cost a fortune for an entire new one if the brackets held during an accident and the fiberglass were all ripped up. Accidents can easily knock it off with little damage simply because the epoxy has let go as it ages. This happens to pieces up on the front of the RV too. My friend had the rear fender get pulled off as we crossed from Mexico into the US one time. It caught a low sign and the entire thing pulled off the back of her RV with little damage to the fender. She carried it home to Vermont in her toad. Just think what it would have cost her if no one had let her know it had ripped off.

I use small 6-32 flat head screws with lock nuts to hold the various fiberglass pieces on the rear and the front after the epoxy gives out. I use the small screws so if it’s torn off like her’s, there’s not much damage. 

Now, back to the heat pump job…

First job after opening the hatch was to remove the panel over the electrical section of the pump and copy down all the info off the big capacitors that are used to start and run the motors, and then get them ordered.

Then I removed the RV’s rear fender to allow better access…And here’s how it appears after the fender is removed. Lots of access over on the right where the heat pump is so that silver air ducting 90 degree elbow can be removed. It has to come out before the heat pump can be moved. There are brackets attached to the pump that hold the elbow’s face plate along with 5 screws to secure it.

Makes the job much easier without the fender in the way. I can reach up along the venting to apply new Venture ducting tape higher up too.

And here’s a couple pictures I found on Winnie Owner’s forum of the venting used that’s similar to my ’02 Winnebago Journey showing the venting to get the cool/warm air up into the RV from the heat pump…

I did try to get to the screws holding the venting elbow from underneath the RV before removing the fender at first but that was just a losing proposition, impossible to get my hand and a tool in there. But with the fender removed, easy to work on the lower section of venting and the elbow. Plus it was much easier to inspect the heat pump mounting.

Once I’d gotten the fender off, every afternoon after finishing work, I’d just hook the fender over the upper brackets that attach to the fender when it’s in place, and then bungee the thing in place to hold it from the nightly winds. Since I’m working in an RV park, putting the fender back on when I don’t need it off keeps the staff from complaining about my working on the rig…though I chose to work here at this particular park simply because the staff doesn’t say much about this sort of thing.

And here’s a pic (below) of the venting elbow and riser box. After I’d removed some of the old, dried out Venture tape. Going by that obvious split there: The lower portion is solid plastic covered with stapled on bubble insulation and it’s inserted into the upper portion which is a custom made, rectangular insulated vent tube. That tube travels up inside the RV’s end cap where it meets a vent ‘Y’, and the air flow is split, which travels up to just below the roof and joins another two 90 degree elbows which are attached to the in-the-ceiling venting. (See above photos above for clarification). The venting above this 90 shown below is a rectangular shape and formed out of 1/2″ insulation. Basically, 1/2″ insulation becomes the tube, until it meets a 90 degree corner, and then they used a plastic elbow.

The elbow has a face plate that is screwed into the side of the pump with 5 sheet metal screws over the air discharge hole in the heat pump where the cool or hot air comes out. The elbow is wrapped with aluminum faced bubble type insulation stapled onto it. Then the seams are covered with Venture tape. This was all done at the Winnebago factory. I’ll have to clean it up and reapply some Venture tape to where the old tape had peeled off due to age and weathering. That section of the venting is exposed to road conditions when traveling so it’s not hard to imagine the insulation wrap becoming a bit worn. I was happy that the previous owner hadn’t driven the RV over salted roads too often because my undercarriage is in better condition than most.

In the above picture note that I’d already taken off some of the old Venture tape the factory had applied to the union and it was pretty easy to get off as the adhesive had started to fail. I cleaned it all up so new tape would stick better when I reassembled the union. There was also some gooey butyl tape there that I pulled out of the channel. Later when reassembling, I didn’t bother putting more in, leaving it for the Venture tape and the bracketing on the heat pump to hang onto the vent and prevent leaks.

One of the screws holding the elbow to the pump was kind of over tightened at the factory so I had to cut that one off but most of them came out easily enough, even with the rust on them. The remaining foam seal isn’t in good shape so that will have to be replaced. It didn’t entirely seal there anyway as it was pretty ripped up when they installed it because it was too thick (1″ X 1/2″).

Because the foam insulating tape was so obviously ruined during installation since it was too thick, this time I used 1/4″ closed cell sticky back insulating foam tape. That thinner tape made it much easier to slide the vent onto the pump. And once the screws are tighten, that tape worked great, much better then the badly installed 1/2″ foam Winnie had originally used. I did prep the elbow’s plastic surfaces by trimming high spots, something they didn’t have time to do at the factory. And cleaned up the metal surface on the heat pump as best I could. With the rear fender off, there’s plenty of room to do whatever prep is necessary here. 

And the above pic is how the connection for the venting looked after I worked and worried the vent elbow off the pump. There’s that rust along the bottom of the heat pump and up the side wall I spent some time with a rotary wire brushing removing. Then I painted the rusted spots with Jasco Prep & Primer to stabilize the rust. Later I found that water from condensation would puddle just inside the air vent opening. So now I know where that rust is coming from, but not how to deal with it. I’m not sure it happens too often because the rust wasn’t that extensive so it apparently only happens occasionally.

And here’s a pic of the vent elbow after removal. This part must be removed before the entire pump unit can be pulled out from the RV. It’s formed of heavy plastic and it’s not delicate so you can work it back and forth pulling downwards to release it from the vent tubing above and at the same time the brackets on the pump without damaging it. That is, after the 5 screws holding it to the pump’s case are removed. The factory also used butyl tape along with Venture tape on the upper union. The upper part is forced into the insulating tubing and Venture tape holds it in place while sealing any potential leaks. I’m not sure how the upper ‘Y’ is attached to the venting above it but I did try to support the upper portion of the venting I could reach while I tugged on this piece trying to remove it. Didn’t want to have to remove the entire end cap if one of the upper pieces was tugged loose.

And after that elbow was removed, then it’s on to lowering the entire heat pump assembly so it can be pulled out to work on.

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This model of Winnebago used two 1/2″ – 13 TPI 3″ long bolts to hold the tray the heat pump sits on in place. The tray also has hooks in the back rather than bolts and that allows the tray and heat pump to rotate down after backing off only those two front bolts. (One reader told me that their’s has 3 bolts holding the rack). This allows the top of the heat pump to be slid out from under the upper metal lip. The bolts and nuts holding the tray had badly corroded. The one near the rear of the RV had better access so I used my Jig saw with metal blade and cut it in half after I’d loosened it a few turns. Tossed it along with the nut and washers. Then I installed a new bolt (same size), washer and locking nut and cinched it up as I still had the other side to work on and I didn’t want the tray to drop unexpectedly with that heavy heat pump on it once I got the other bolt loose.

Moving on to the front bolt, found there was no way to get in there to cut it while the heat pump was in place. And unlike the rear bolt, the front bolt was welded to the frame. I bought a 1/2″ breaker bar and after P-B Blaster juice on it over night, it was still a chore trying to turn it. Took what seemed like hours and a few bruised knuckles to just get it turned a few turns with the breaker bar before I figured out I could use heat. I’d bought a torch size tank of propane down in Parker when I was working on the broken serpentine belt so had it on hand. Eventually, using the torch to heat up the nut, found it much easier to turn the bolt a few turns using a 1/2″ ratchet, then when it got harder as it cooled I’d hit it with the torch again. Once out, I replaced it with a new bolt, flat washer, and lock washer. Had to reuse the old rusty nut because it’s welded to the frame. There’s no room to do much of anything about the welded on nut so I’ll just leave that there and hope for the best. After the heat pump is repaired when it’s time to tighten these new bolts, I’ll use lithium grease on them and cover the threads (ended up using Venture tape wrapped around the threads like a hat along with the lithium grease) to prevent grit and grime from attaching to the threads again.

And below is a picture of that corroded bolt that took so long to remove. Only repeated applications of a torch flame directly to the nut made it turn easily enough to remove the bolt. An impact wrench would have worked best but I don’t have one, though the worry would be breaking the bolt off before it was out. A reciprocating saw with metal blade could have reached in there to cut off the bolt head, but then what? Without the bolt head on there it would have been very difficult to remove just the threaded shaft from the nut, not to mention coming up with some way to slowly drop that side of the tray to get the heat pump out. I simply chose to keep working at unbolting it rather than trying other methods to remove it. The nut was really welded on that bracket well. Once I could see in there after the pump was out, I had to marvel at the great workmanship involved in the welding. It would have been nearly impossible to get the nut cut out of there and still have a usable bracket to hold the heat pump tray if the bolt had broken or the nut ruined. As I said an impact wrench probably would have been the easiest solution if used carefully and with heat. What I could have done after the bolt was out and I’d removed the heat pump, would be to drill a clearance hole through that bolt and than just use a new bolt. 

After the corroded bolts and one nut plus hardware were replaced and usable again, I unscrewed them a few turns one side of the tray at a time while I pried on the upper edge of the case with a flat bar until the top of the heat pump was below the upper rail. When it was possible to pry it out, there was about 1/2″ of threads left on the two bolts.

With the help of a neighbor, we pulled the pump out the rest of the way and set it on top of two screwed together 2″ X 6″ boards set on top of upside down plastic pails. It’s heavy especially on the compressor side, and you don’t want to drop it, but it sits nicely on the bench with no tenancy to wobble or tilt. And two guys have no problem lifting it. The electrical cables are long enough to remove the pump without having to disconnect a bunch of wiring. Here’s how it looked just before I lowered the tray and pump.

Here it is after I’ve dropped the tray a few inches, and pried out the pump carefully…one side at a time. Now my helpful neighbor and I could grab the sides and pull it out. Not that hard to do and though a bit heavy on the compressor side (pictured below), not too heavy. Didn’t take long to get it out and on the stand. Not counting the time taken to free the bolts holding the tray.

And here’s where the wiring cables enter the case. There are two armored cables down low and then this gray multi-wire cable that goes to the thermostat and controller at the EMS panel. There is plenty of slack in the cables to pull it all the way out of the rack.

And once it was out, it was time to remove the screws on the top and top edges holding on the sheet metal. Just a few minutes later and the top was off.

Here’s how it looks after the cover is removed. Not too bad, I thought. Not too much rust or debris. The rear of the outside fan was looking a bit gunky but it runs. Coleman named the near fan (in the picture below) the ‘outside’ fan, and the other one the ‘inside’ fan. BUT…that upside down U of copper tubing that goes way over the squirrel cage fan might be problem. What were they thinking with that design??? Is there some secret way to get the fan assembly out? Gah! Remember, this picture is of the outside fan that’s making all the noise, not just with mine but with many other owner’s heat pumps, and it’s the assembly that needs to be removed if I replace the squirrel cage fan too. It’s large and barely fits inside there. So it would be very difficult to get it out. The pictures that Duner of iRV2 dot com posted that I used as a guide for this job don’t show that U of tubing on his model. Jeese.

Now with the heat pump out and with access to the whole thing, I did what comes naturally, I tested it. And it was rattling a little and squealing a little. There are two motors with fans and bushings in the case, but inspection showed the larger one shown above was the rattling-squealing one, as expected. But after I shut it off and oiled just the motor shaft bushings (the big bushings on the ends of the fan shafts), low and behold, both symptoms disappeared! Doh. I had bought a new plastic squirrel cage fan because I thought the rattle was caused by a bad fan but I guess not. And I’d bought a set of pillow block ball bearings to replace those motor bushings too. Remember that this is a 2002 Coleman Mach so I expected to have to replace these things, but I found that maybe the bushings just needed some TLC? And the fan hub wasn’t cracked or broken, so why replace it? I did notice that the compressors seem fine, they cool the coils quickly like they’re suppose too. One of them has a bit of excess vibration but I know that compressors sometimes do that for years. I used my vacuum to clean the fins of the condenser and evaporator assemblies. They weren’t all that bad looking after all these years of use so that is good. Means the filtering is working.

Also cleaned out the intake behind the pump. It wasn’t that bad looking either. The foam seal was in pretty good condition too so I straighten it out and I gave it a good vacuuming. This is the air intake for the pump that comes from the filtered grill assembly attached to the side of the bed stand.

Since at first it didn’t appear that the fan in this model could be removed without completely dissembling the entire case, I used WD-40 to spray the shafts and bushing as well as I could to clean out the grit. Then after the WD-40 had dried a bit, added oil to the oil fillers and boy were they thirsty. There’s absorbent packing around the bushing to hold the oil and they took a surprising amount. I used 5W-30 Fully Synthetic. It ran very quietly afterward but I’m still going to replace the bearings once I figured out how to get them out. Had to think on that because it didn’t seem there was enough room to get them by the interfering equipment near the ends of the fan shafts.

Seems as though I might have bought too many parts. I mentioned the oil quieting the noises for readers who just want to do the minimum maintenance though I do recommend replacing the bushings with ball bearings.

Here’s a shot of the smaller fan assembly, the one that sends the cool/hot air into the vent riser and on into the RV. This one is nice and clean, free of rust or gunk. The evaporator fins were pretty clean too. The bearing I’m planning on changing is on the end of the shaft not visible in this shot.

Meanwhile, I wasn’t going to let the opportunity of having this access to the pump slip away without replacing all the motor and compressor caps. It’s recommended that if you’re in there anyway, might as well replace them. So that’s what I’ve done. Several of the caps I’ve replaced are shown in this picture, they’re the cylinders at the bottom of this cabinet. There is another 12.5 MFD, 370 VAC motor run capacitor mounted on the case of the big fan so it’s not in this picture.

Caps replaced:

1X – 7.5 MFD 370 VAC RVP 1499-5461 $17

2X – 88-108 MFD 165 VAC w/starters 833ZA9021 $21 (Hard Start)

2X – 30 MFD 370 VAC 1499-5741 $16

1X – 12.5 MFD 370 VAC $10

So I have all the capacitors replaced now, and I’ve noticed a significant improvement in operation. There was a loud bang when compressor #2 started up, and the outdoor fan would slow. The voltage also dropped according to the indicator lamp fault code on the control board. But now that all the capacitors have been changed, that doesn’t happen. Some of that had to do with the oiling and new ball bearings but it was making that noise after all that but before I replaced the 12.5 MFD cap. Once that was replaced, it’s quiet. More of a thump than a bang now.

I measured all of the old caps and though they are all reading the right MFD’s, or close to it, they could have leakage or a high ESR so I just feel more comfortable with them replaced. They are 20 years old after all.

I’ve also swapped the wiring of the two large compressor relays as a test (didn’t see any operational difference so pronounced them good for now), and using a shop vacuum cleaned up the fins and the air intake. After I replace the bushings with bearings and all the capacitors I should have this project finished and the heat pump ready to re-insert in the tray and push it back into the chassis.

Once that’s done, then I can use foam tape & Venture tape to seal up the air outlet to heat pump elbow. The air return foam seal is in good enough condition that I don’t expect to do anything to that. It’s already been cleaned and looks good.

While I was in there, I noticed that both fan motors have oiler tubes (which is typical for fan motors) so I went to Walmart and bought a 3-in-1 bottle of oil with the 6″ oiler tube extension. The lack of oil can cause the motor to be hard turning so that can ruin the motor itself, the start capacitor, the run capacitor, or the motor relay, so it’s important to oil those motor bushings along with the shaft bushings.

The motor fan shaft bushings also require care and periodic maintenance as they have fiber packing around them and over time the oil in them disappears. The lack of oil there often causes motor squeal. It can also cause a rolling type vibration that owners can hear and feel inside the RV. Here’s what one of mine looked like after I pulled it out. This is the outdoor fan bushing. The indoor fan bushing didn’t look as bad. Less filthy.

I wanted to make a permanent fix so I installed ball bearing types instead of just cleaning up the bushing types used originally. Just cleaning them had taken care of my squeal (as far as I could tell) but I wasn’t willing to depend on just that, so I replaced them with ball bearing type pillow block bearings. 

There’s one on each motor. Both of them took some scrunching to get them in as there is barely enough room between the end of the shaft and the radiator in the case of the inside fan and the end of the shaft and AC parts on the outside fan. On the indoor fan, I had to squish the fins on the evaporator allowing an extra 1/4″ to wedge the old one out and the new one on. Then I used the fin comb to straighten them out again. The outdoor motor bushing I had to push/pull on compressor components to spread them apart enough to get out the old one and the new one in place and on the shaft. Only a matter of 1/4″ in either case. I also could have ham fisted it and just ground or cut off 1/4″ from the end of the shafts for more room but that didn’t appeal to me. 

The new pillow block bearings were purchased from Granger, made by Dayton p/n 2X897 (1ea) and 2 are needed for this heatpump.

I didn’t need to work hard at getting the Pillow blocks in the right place and screwed down, the motors are already tightly held in place and were stable enough that the clamps lined up with the ghost outlines of the ones I removed so I just screwed them down in the same places.

After those new ball bearings are installed, I notice that everything is significantly quieter. But I still had a big THUMP when compressor #2 starts. It sometimes causes an error LED on the control board to indicate loss of voltage to the fan. That’s when I figured out that the motors themselves have to have their shafts bushings oiled too. There are little plastic yellow caps that are plugged into the oiler tubes on either end of the motor for that. As shown in this gallery, the oiler tubes are easy to get to on the exterior end of the motors, indicated by those yellow plastic caps, but the interior ends are covered by the fan cage and are a bit more difficult as the first picture in this gallery shows. On the inside fan motor I could reach the oiler hole easily with my hand to guide the 3-in-1 tube into place. I did need to bent a nearly 90 degree curve into the tube so it would go into the hole for that motor. But it wasn’t kinked.

I did consider not oiling the motors, but I don’t want to come back in a few weeks to replace a motor or have to oil those motor bushings if they started to squeal so now’s the time to do that while it’s out and the case is open. Here’s a Youtube video I used as a guide.

The outside motor was a bit more difficult as it was nearly impossible to see inside the cage or get my hand in there easily so couldn’t use the same method. Had to come up with a different plan and what I did was drill an inspection hole into the cage. Here’s a picture I took as a guide to the placement of that oiler tube on the end. I couldn’t get my head down in there so the camera came in handy. 

It’s easy to reach the oilers at the exposed end of the motors. This shot is of the inside fan motor and it’s smaller than the outside fan motor so I could reach the front oiler tube with my fingers.

The oiler extension tube that comes with the oil packages comes in handy. Here I took a shot of the grunge and rust on the back of this motor. Not sure what to do about it, and after the motor was oiled, start cap replaced, and the new ball bearing installed it was quiet enough not to worry about.

I didn’t remove the fan cages or the motors because I’m not sure how to get the outside fan cage out and didn’t need to for the inside fan cage, because I was able to squirt oil into the oil filler tubes with the motors in place…with some difficulty for oiling the interior bushings. Each bushing took nearly 1/4th of the bottle of oil so they were thirsty and in need of a good oiling. These motor bushings are inside the motors and not the same as the squirrel cage fan bushings. Those hold the end of the long shaft that holds the fan, which I replaced with ball bearings earlier. And there’s only two pillow block bearings where as there’s 4 of the motor bushings. All 6 get oil. Note that I could smell 3-in-1 oil throughout the house for a week after this oiling, whenever I ran the AC, but it eventually faded. I find the smell pleasant.

Of special note was that accessing the bushing on the big outside blower motor interior was difficult because it’s very hard to reach due to lack of space, but what I did was measure it’s position, and a mirror came in handy while working on this fan, then transferred that measurement to the cage case, then just drill a 1/2″ hole in the case over where the motors oiler tube is so I could look down in there. I was careful to ONLY drill far enough to make the hole. Did not want to damage the fan blades so made sure the drill didn’t penetrate too far. Put vinyl tape on the drill bit as a stop warning. That would have been a disaster if the bit penetrated too far. Used a couple magnets to attract and capture any metal chips. Drilled slowly and carefully. I measured the position of the filler hole at 4 & 5/8″ from the left edge of the cage and that turned out to be correct. Used a T square to align the hole with the motor.

After drilling the hole I could insert the 3-in-1 bottles tube down through the squirrel cage fins straight to the oiler and guide it in with my fingers. To prevent too much oil from dribbling out when I did that but before it was inserted, I unscrewed the long tube off the bottle while I was searching for the motor’s oiler hole and than reattach it to the bottle when it was in place. I’d saved oiling this bushing until the end of the job so there was only 1/4 bottle of oil left, less chance of making a mess if I spill. I later just patched that hole in the fan cage with furnace ducting tape, after cleaning the metal so it would stick of course. I’d been careful so had very little in the way of metal filings to clean up. I used a magnet to sweep the areas I could reach.

Once all those motor bushings were oiled, hey, no more LED fault light. The motor does drop down to a slower speed when compressor #2 starts, I believe it’s suppose to do that, but no more really big thump when it does. Pretty happy with the operation now. In fact, I’m expecting more years of great operation. This heat pump is really perfect for a full timing RV’er, IMO. I might need to use it for heat or cooling for weeks at a time and when it’s working well, it’s really comfortable. I especially like how quiet it is. Just a gentle breeze coming out of the ceiling vents most of the time, and a slightly stronger breeze if I’ve just turned it on and it’s hot or cold inside. I can hear the TV or phone when it’s operating. Not something I could say about the ceiling A/C I had in my old Bounder RV.

All together, this job has taken several leisurely days, and now that I’ve gotten the experience doing it, I think a good shop with proper tools would be able to complete all the work I’ve done in 3 hours or so. Add another 2 to 3 hours if the squirrel cage fan or one of the motors or compressors needs replacing. Sometimes, there are so many items that have gone bad (and this would point to lack of owner’s maintenance like I’m doing now) that it would pay just to put an entire new heat pump in the bay. I’m trying to avoid that by doing the best repair & maintenance job I can. New pillow block bearings, new motor capacitors, restoring the foam seals, and oiling the motor shaft bushings will hopefully give many more years of trouble free operation. I was thinking of replacing the motor start relays, but everything sounded the same when I’d swapped them so for now I’ll leave them in. They’re under the easily accessible electrical panel if they go bad on me.

This isn’t all that difficult of a job except for those badly corroded 1/2″ bolts that hold the tray. With a 1/2″ impact tool and a torch though, it probably wouldn’t have taken more than 5 minutes to get them both out, or at least broken them. The possibility of breaking the bolts is one reason I didn’t go out and buy an electric impact wrench, if the really stuck bolt had broken, gah!, that’s a whole new set of problems since there’s hardly any room to work on it. Turned out that using a torch to heat that nut was the solution that worked for me. I did remove one of the 12 volt batteries in the battery compartment next to the area where I was using the torch to avoid any flame caused explosion. I could get one or two turns per heating, which ultimately prevented breaking the bolt. As I mentioned earlier, I’ll be putting grease on those threads of the new bolts and slipping a cover over them to protect them from the elements so the next time I need to drop the tray, it’ll be easy to loosen them with just hand tools.

So now was the time to work on the venting. Starting with the elbow, I first removed all the loose ducting tape and cleaned the elbow with Awesome and let it dry. Then I applied Venture tape to any open spots in the insulation done at the factory from the previously removed loose ducting tape that was wrapped around the elbow to cinch it all together. Then used a sharp knife to cut or peel off high spots and drill hole debris the factory people didn’t have time to remove from the face of the elbow…where the ruined foam seal had been. Then applied new 1/4″ thick foam insulating tape as shown here, the sticky backed closed cell foam tape I had in stock so didn’t need to buy that, but the Venture tape I bought a few days earlier from Amazon.

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Now it was nearly ready to put all back together. Just had to put the sheet metal top on and screw it down. After that was completed had a neighbor help me lift it back into it’s cubby hole. After it’s inserted around 2/3rd of the way, have to adjust the electrical cables to prevent interference. For the last 1/3rd I did have to drop the tray about 1/2″ to get a better angle with the pry bar in order to force the pump up against the foam seal in back so there would be a good seal and the pump would be inside the upper lip. Left the pry bar there to guide it back behind the lip while bolting up the tray. Moving from one side of the pump to the next, back and forth, I wrenched those large 1/2″ bolts which raised the tray until the pump was in position just behind the metal lip, removing the pry bar when appropriate. I had marked the pumps position on the metal lip before I removed it so I adjusted it to line up with the marks as I went along during reinstall.

Once the pump was in proper position and the rack lift bolts tightened, attached the vent elbow to the pumps air exit. After adding the 5 screws; 3 along the right side, and 2 at the bottom, there were no air leaks that I could detect from that interface.

Then moved on to the upper part of the elbow where it attaches to the rectangular riser venting. There I used two complete wraps of Venture tape to seal up the small gaps. The two pieces of venting don’t quite mate up and didn’t at the factory either so the tape was my solution. I didn’t feel any air escaping after applying the tape.

So all that’s left to do is to close and screw in place the door, and then the rear bumper. All easy stuff requiring 4 metal screws into two brackets and I’ll just show a couple pics of where the door attaches…

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And last but not least, here is the picture of the control box with all the new caps held in place with metal type plumber’s tape. I’m not worried about them moving about while traveling, but I will check in a couple months to make sure they didn’t come loose. I dated all the caps so if the pump is ever serviced again whoever does it will know when they were installed.

So far, this job has cost just over $250. This includes all parts plus supplies and the tools I bought specifically for this project. I did order a new plastic outdoor cage fan. The original is all metal and they have a pressed and crimped on hub. If things didn’t originally go perfectly during assembly by the OEM, they tend to crack around the hub because of the heavy pressure during assembly and the stresses of operation. Running the fan over time causes the cracks (if any) to widen or creates new cracks eventually causing the fan to come loose from the hub and rattle. The fan shaft bushing going bad can cause a vibration in the fan as it spins that can cause cracks too.

In my case, it wasn’t the fan hub rattling like I thought, it was the fan’s dry shaft bushing causing a similar noise. Now that I’ve replaced the bushing with ball bearing and oiled the motor bushings it’s so quiet that I feel confident that I’ll get several more years out of the motor and metal fan. So I’ll be sending the plastic fan back to RV & Auto Parts. The cost for that Coleman P/N 14721161 was $54, plus $11 shipping for a total of $65. When I return it, I expected to pay the shipping and a 15% restocking fee, but that wasn’t the case…the receiving forgot to tell the office so weeks later when I asked about my refund, they were kind enough to give me the entire $65 back because of their mistake. The fan cost isn’t in the total amount above.

Since I’m saving so much doing this job myself, I think I’ll buy myself a present with $125 of the savings. O’Reilly’s Auto has a nice 20 volt Li-Ion operated 1/2″ impact wrench I’ve had my eye on. I wish I’d had it when I was trying to get those tray bolts out. I already have their 3/8″ impact driver and it’s well built. Hopefully the 1/2″ tool is as good. O’Reilly’s gives a 10% veteran’s discount too.

If you have noticed a slight rattling from your heat pump, don’t wait too long to get it serviced. The longer it goes, the more expensive it’ll be to fix. I had a drop back position (plugging into 30 amp so it was quieter when operating as an A/C) and specifically headed to a place where I could work on it without the parks interference, a place where the weather was great for working outside. It took a week to get it all done and I did it without rushing. Some of that time was waiting on parts I’d ordered too. There were only a couple days were it got pretty hot in the RV, as the cool April breezes here in Pahrump kept it comfortable most of the time. Like I mentioned earlier, I suspect a shop could have it done in one day, if the parts needed are on hand and I suspect 2-3 days if they ordered as soon as possible after determining what was needed. But with the way RV shops work these days though, I wouldn’t count on the 2-3 day thing, more like a month to 6 weeks. So really, to avoid a sweltering summer waiting for a repair it’s best to do your own work if you can, and hopefully, this guide will help.

Thanks for reading! Let me know if you have any questions, comments, or suggestions.

Edit: June 18, 2019

It’s been a couple months since I did the maintenance on the heat pump and I wanted to write an update. It’s been hot often enough that the A/C has been run for many hours over many days over several weeks and I am happy to say that it’s worked flawlessly, quietly, efficiently. BUT…there are mornings when it’s been pretty cool and I’ve wanted to run the ‘heat’ part of the pump but it’s not working. Never turns on. I’ve got plenty of electric heaters so it’s not a big deal but I figure I didn’t connect something right when I was messing in the electrical control area so I’m going to dig into that next week. I would like it to be operating properly. Working on it doesn’t require removing the heat pump since I can test without doing that. I’m in a place where it’s nice and cool for several hours in the morning and I’m hoping to find the problem fairly quickly over the next week or so. [Edit: Working on ‘Heat’ now, see True Air Thermostat for info…]

Update, June ’20: Still working great. Still as quiet as when I finished this job back in April ’19.

Update, Dec. ’20: I’ve gotten hundreds of operating hours on it now since I did this work and it’s behaving perfectly. Fingers crossed for several more years of excellent operation. I’ve used both the cooling all summer and the heat nearly everyday this winter and I’m happy to report that the heat pump and fans are still running quiet as a mouse. One thing I noticed when I was up in the Walla Walla valley and it got down to 28 F that the heat pump still put out heat. Takes a long time to get to that point when it’s that cold, but it was still working as a heat down that low. The experts say 40 F is it’s low limit. However, the weather changed and it got slightly more humid and it did stop heating.

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Update, July ’21: Sitting in my easy chair yesterday during a 97ᵒ day, smelled something weird. Jumped up and found it was mostly in the living room coming out of the venting. Ran outside looking for smoke…none found. Discovered over the next hour or two that the #2 compressor wasn’t running. Opened the basement door and then the control circuit door on the Coleman and discovered carbonized wiring around and to the two big relays as show below. The devices I decided to not change out and leave for later back in ’19. One of the relays coils is open circuit and the jumper on that one burnt up and fell off, removing power from the #2 compressor.

I found replacements at eBay: TE CONNECTIVITY POTTER & BRUMFIELD T92S7D22-12 POWER RELAY, DPST-NO, 12VDC, 30A FLANGE

I know that these Coleman’s are well designed but the stress the mistake I made of not replacing those relays back in ’19 may cause one or both of the compressors to go bad. The #1 compressor was running on 8 amps for I don’t know how long due to a poor connection and that’s not good for them. It’s back up to 15 amps which is normal now that I’ve cleaned the contacts and connectors but it’s still a worry. And the PCB may have been stressed somewhat too when the #2 relay went bad.

Hurriedly ordered the replacement relays from ebay where currently they are $21 each with free shipping from California so I should have them in 3-5 days. Meanwhile, wanted to test my #2 compressor and have max cooling in these 100ᵒ days so grabbed my box of automotive 40 amp 12 volt coil relays that I stock and made a DIY set of DPST contact relays by wiring a couple of them together. Note that these are rated at 40 amp @ 38 volts so it’s just a temporary fix. Not going to leave them in that 120 Vac circuit longer then necessary. Note that compressor motors typically draw 3X the run current when starting. So those contacts will see ~36 amps for short bursts plus some arcing they’re not designed for. 

That’s all that was needed as it started shortly after I flipped on the 50 amp shore power breaker…the fans came on, then the #1 compressor, followed shortly after by the #2 compressor. So nothing seemed to be damaged other then the relays and wiring which I trimmed back and it’s been running several hours now with the pump pouring out cold air as needed.

Much success! Yea! AC running both compressors! Really need it here with the sun beating down on the front of the RV in the afternoon. I can now feel the difference in air temp out of the vents with both compressors running. With just one, it’s cool, with both, it’s cold.

Update, June ’22: So after over 3 years, I’m still happy with the maintenance I did back in ’19. Did have those relays burn up in ’21 but them going bad and flaming the wiring didn’t seem to harm the operation as I’ve used it extensively since they were replaced (see above) for days and weeks of either heat, cooling, or on some days, both and it’s worked flawlessly. Spent a couple weeks in Mojave, CA when it was averaging 104 F and it was running nearly continuously for all day and into the night and it worked great…on a 30 amp circuit too. Kept me comfortable.