New Pool Pump

Earlier this month, I started work on replacing our pool pump, and as I write this, it’s mostly finished. I’d file this project under things I’m happy I did once, but wouldn’t want to do again. A hot swap of the old pump, with no plumbing or electrical changes, would have been quick and straightforward, but I completely redid the intake plumbing as well as the pressure-side plumbing between the pump and the filter, so that I could add unions (plus, the old pump had 1.5″ connections and the new pump has 2″ connections). Everything needed to be rewired as well, as the old pump was single-speed, and the new pump is variable speed (VS). The old pump used to be scheduled and switched on and off via the Autopilot SWG controller, but with a VS pump, it’s the other way around: VS motors have on-board electronics that control the pump schedule, run speeds, etc., as well as an auxiliary load circuit that will switch the SWG controller on and off as needed. The project was rather all-consuming for a week or so, as I really wanted to get the pool water circulating sooner than later so that it didn’t turn into a giant swamp (the longer you wait to Chlorinate in the spring, the more of a pain it is to get the water cleaned up for opening). I also wanted to make sure the pump, which cost upwards of $1200, actually worked.

The plumbing part of the project was the most challenging, but it went rather well, thanks to very careful planning and measuring. I built a platform for the pump out of scraps of Trex, and the biggest challenge was getting it level. While the pump doesn’t need to be level to work properly, it makes it a lot easier to get the pipes to align cleanly. I used the platform and some plastic shims to get the intake union lined up. I think a better solution might be to add adjustable feet to the platform, so I might do that for next season.

In my earlier entry, I mentioned that the suction pipes from the pool came out of the ground at different distances from the house foundation, meaning that if I wanted the pump exactly perpendicular to the wall, I’d have to either add extra 90° elbows, or use a specialty adjustable elbow on the intake. It turned out that in practice, it wasn’t really worth bothering with this — yes, the pump is not perfectly square to the wall, but the angle is so slight that it’s hardly noticeable. So, I got to save my adjustable elbow for a future project.

The other challenge was dealing with the water in the pool. A very rainy March/April had left the pool full to the brim, and since the pump intake is slightly below the waterline, water was constantly trying to overflow out of the main drain suction line once I cut the old valve out. I didn’t want to drain water out of the pool, because it’s convenient to have the water high for vacuuming to waste during opening. So, I had to figure out a way to keep the water at bay while I glued new valves to the suction line. I ended up taking a #8 winterizing plug and flipping the bolt around so that the wing nut was on the narrow end of the plug. Then, I jammed the plug down the pipe, tightened the nut, and glued the valve on. Once dry, I was able to pull the plug out through the valve body. Flipping the nut and bolt made this possible (in the regular orientation, the wide end of the plug would have gotten stuck).

Compared to the intake, the pressure side piping was a piece of cake — just some careful measuring. Unions made things easier, but it’s still a challenge making sure everything lines up, and I had to be careful not to drip PVC cement on the union threads or mating surfaces, which can be easier said than done.

I was rather nervous about starting the pump for the first time, but it worked just fine, and there were no leaks (I was fairly confident about the intake side, as it held water for a couple of days while I was working on the pressure side). The only real issue I had was unrelated to the pump — the handle shaft o-rings on the filter multiport valve were leaking. I ended up taking the valve apart, flipping and re-lubing the o-rings, and adding some teflon tape around the notch in the shaft where the o-rings sit. It seems to have stopped the leak.

I’ve been running the pump for the past few days to add chemicals and also break the pump in and observe how it works. I still need to wire the auxiliary load side to get power to the SWG and the pool cleaner booster pump. Then, I’ll need to figure out the minimum pump speed that I can use to get effective chlorination, as well as the minimum speed needed to effectively run the pool cleaner. But the end is definitely in sight for this project.