The Pope Pond Pump repair…

The Pope Estate has a large man made pond with a waterfall and all. It’s been stocked with four trout this year and I was assigned to get the recirculating pump (RP) running. I was told that the pump system had been a headache for several years but they had been able to limp along with it. Now they wanted it working right because of the fish. The fish were there to keep the pond cleaned of bug larvae (Lake Tahoe has a vigorous mosquito population).

The RP/waterfalls also help keep the water in the pond oxygenated so the fish wouldn’t die and algae wouldn’t overtake it. This was necessary because the overflow water goes into the lake and must meet cleanliness guidelines. City water is added to overcome evaporation and to keep things fresh. If they tried to use city water only (spilling over the man made falls), which they did often because the pond pump was out of service so often, that areas pressure would drop to a point that endangered all the plants around the estate. We had an automatic sprinkling system that would become water starved, and the volunteers would be out for a couple hours every morning dragging long hoses around trying to dampen dry spots the sprinkling system was suppose to cover. A properly working pond pump would allow less city water be used so the sprinkling  system would have more water which keeps more plants alive. It gets very hot during the summer at Tahoe.

The excess water overflows the pond and is channeled into a small creek that spills into the lake. We thought that the pump recirculates 2/3rds of the water in the pond over the small waterfalls (there are four) and the city supplied 1/3rd replenishment water. We don’t know for sure as there are no instructions or drawings of the water system anywhere. (Update: A couple weeks after I did this work we did finally find the pump/city water plumbing drawings and they verified what we thought was happening).

I hauled the pumping system parts out of the barn where it’s stored during the winter and connected it all up at the pond and…nothing. Wouldn’t draw water from the pond down to the pump. Priming the pipe inlet to the pump resulted in an obvious leak right at the coupling between the pump head and the pond pipe. I know next to nothing about pond recirculating pumps but I did want to work on it. Since I knew they’d been having trouble with the system for several years, and now that there were fish in the pond we wanted to keep alive, I knew I had to do something more then previous volunteers had in previous years. So I really looked at the pumping system, and the leak was an obvious tip off that something wasn’t right.

What seemed to be happening was that the major leak at the connection between the plastic plumbing and the inlet to the pump was sucking air, so the water wouldn’t siphon correctly over the edge of the pond and down to the pump. Time to take it to the shop for a close up inspection.

Here’s a shot of the inlet to the pipe, which then runs down the hill to the pump, the white piping connects to a large filter that is shown in the next shot:

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This is the screened debris filter that’s immersed in the pond and attached to the piping shown in the previous shot:

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This is down hill from the first shot, the pipe is buried by forest fodder, the slope is steep and the drop is around 6 feet. The white plumping connects to the pumps inlet and that large connection is where the big leak was. The white pipe is 1 & 1/4″ PVC and is comprised of a threaded coupler and sealing surface with rubber O ring. The blue thing is a large debris filter, the pump & motor assembly is in the shop:

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Here’s a few shots of the pond, while touring the estate, this is often where visitors like to hang out to rest so we wanted to give them a nice experience without looking at a scummy pond or having to battle mosquitoes:

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The gazebo next to the pond:

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This is the rock garden where the small waterfalls feeding the pond are located:

After I got the pump back to the shop, I discovered that the big white threaded coupler at the pond has different threads then the inlet screw to the pump! (For you experts, the plastic pump inlet is national coarse threads, the PVC piping is national fine threads). It’s been this way since it was installed in 1994. Twelve years of improper operation. Why the first installer didn’t see it and do something about it is beyond me. And all those volunteers or Forest Service people that worked on it every year since ’94, why didn’t they notice or if they did, do something more permanent about it?

Over the years it’s just gotten worse and leaked more and more as when the large coupler was tightened on the inlet, it would cinch up to a point and then slip a thread. The treads were getting worn because of that. I suppose the installer would be a volunteer like me and they would just cinch it as tight as they could and move on to the next project, allowing a leak. Sometimes one of them would use many layers of Teflon tape to try to reduce the leak.

After identifying the problem, what I did was to cut off a piece of threaded PVC from a spare threaded coupler and glue it to the inlet to the pump, right on the front of the threaded inlet provided by the manufacturer. I did call them to try and find a correct part but they don’t make one with fine threads that fit this motor assembly. All they wanted to do was sell me a new pump with fine threads. The surfaces were easy to get nice and flat using a belt sander and then I used PVC glue to get a very good seal. Took all of an hour or so to come up with a low cost fix, not counting the time on the internet finding info on the pump, time on the phone to the manufacturer, the trips to town to find parts that might work as replacements, etc. Previous volunteers had suggested a new pump, at $300, but I didn’t like that idea for such a simple problem.

After gluing on the new piece, and testing with the white 1 & 1/4″ PVC nut and coupler shown there on the bench, it seemed to be a very good adaptation. The pipe sticking straight up from the pump is the outlet which goes to the blue debris filter, the white thing on the front of the pump is the new, fine threaded inlet. You might wonder why I didn’t try to find a metal coupler that would fit on the pumps inlet with a union and transition to standard plastic. I did go around town and look, but all I could find with coarse threads were brass parts which were very expensive, and I had a very small self-imposed budget for this project. The way I did this repair only required modifying a $3 plastic part we had on hand and some glue. And as a plus, didn’t require any modifications to the existing plumping at the pond.

Well, my modification to the pump seems to work quite well. Back at the pond the plumbing couplers were hand tightened and no plumbing tape used but even then there are NO leaks. Pump pressure was strong and I could reduce the water from the city supply over the falls. Yeah!

Here’s the pump installed after the modification:

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Here’s another view:

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Here’s the whole assembly enclosed by a wire screen ‘dog house’ to keep out the curious:

With the pump now working at full capacity, the gardeners were very happy that they didn’t have to spend the rest of the summer fighting with hoses to keep the gardens watered as the city water pressure was now high enough (since it didn’t have to supply so much water for the pond) that they could actually use the installed sprinkling system as it was intended. There were now nice robust sprinkling patterns all around the estate. As a bonus, the gardeners now had the water pressure to work the estates original garden and they happily got right to work on it. They’d not been able to work it for several years because of the water pressure issue.

The Forest Service director was happy because it was reasonably certain that the fish would stay alive this year (the previous year, the first year they’d re-stocked the pond after a several year hiatus, they had not done so well and died), and that the money she’d set aside for a new pump could be used on other projects.

And the tourists really seemed to enjoy the pond, some spending hours at the gazebo while their children ran around the pond spotting the fish, free of algae, with healthy fish swimming around, and few mosquitoes.