I think my pump may be on its way out. It's a single speed Whisperflo 1HP (1.65) and I've been told by a couple pool pros that the motor is not original, it's been replaced at least once. Currently it's a black AO Smith motor, which I've gathered is pretty standard issue.
The past couple weeks, I've been having issues with pressure being low. My sand filter's pressure can't seem to get above 17-18psi. I've had a couple pool guys out and they say "don't worry about it -- water is flowing fine" but have noted that my pump does sound like it's seen better days (bearings? seals?). Also, the pump runs HOT. One guy burned his hand when reaching to feel for the filter drain plug, pulled his hand back quickly and said "Holy SH$$ that's HOT!!!". I realize the motors generate a good bit of heat, but I guess mine is hotter than what would be considered normal.
While they may say "don't worry about it" -- the engineer in me worries about it, and here's why. Water may be flowing, and 17psi may be an OK pressure in generic circumstances, but it's not a typical behavior of my system. Something is different, and that's what's concerning me.
I moved into this house in early July and became acquainted with the pool and the system. At the time, the Navigator cleaner was having trouble getting around. I began educating myself, and discovered that the filter pressure was around 30psi -- that's when I learned what backwashing is. I backwashed thoroughly for a good 5-6 minutes and the filter pressure dropped to about 18psi and all was great (the cleaner, however, still had its share of problems and after being rebuilt twice by Leslie's I just gave up and bought a Phoenix 2X cleaner which works much better.)
What I found was it that would typically take about 2 weeks for the pressure to get up to around 25-26psi and that's when the cleaner would struggle, and so I was backwashing pretty much every 2 weeks all summer. Clean pressure was around 17-18, I would backwash around 25-26.
A few weeks ago I noticed a strange noise coming from the pump so I investigated and found that the filter was running at 9psi and the pump was struggling. There was some debris in the pump basket but it wasn't totally clogged... but I cleaned it all out and the pressure got up to about 14psi. I was leaving for a week so I had our housesitter keep an eye on it... she said it stayed like that all week whenever it was running.
In the past few weeks I've had a couple guys out to look at it, like I've said. One of them helped me get the cover off the sand filter (I tried once and it was stuck on so bad I broke the plastic wrench thingie...) and he replaced the O-ring (which I had on hand, I could just never get the cover off!) which resolved a small seepage leak from the filter top. He dug his hand into the sand and said the sand looks fine, in his opinion no need to replace it or anything. Ok, great.
Last week I took the pump motor off the housing (second time I've done this) and cleaned every speck of debris out of the impeller and cleaned some of the grime off the surfaces. I lubed the O-ring and reassembled. No leaks, which is fine, but I still cannot get the pressure to get above 17-18psi.
Water IS flowing. I do get water coming into the pump, it primes and there's no air bubbles or cavitation. The suction cleaner works, the skimmer is moving water, and I get flow out of the returns. It's just not "how it usually is" and I'm not sure what's up. I let the filter go for a good 4 weeks without a backwash and it never got above 18psi. I have just as much (or more) debris falling in the pool daily now as I did all summer, and the water condition is the same, so the filter should be getting as much or more of a workout, no?
I've noticed that even a small buildup of debris in the pump basket causes the pressure to start to drop. I was just out there and I turned the pump on to check it, the filter was at 16psi. The basket had a small amount of very small leaves in front of the impeller. I cleaned it out, and I'm back to about 17.5psi.
Is the logical conclusion here that the pump is just dying and losing its ability to push water at the same pressure?
I'm sure it's not often people WANT their pressure to get higher in the filter, but to me that would indicate a more normal behavior.
Side note: I have a home warranty but they won't replace the pump unless it's DEAD. And, at that, they'll only cover the cost of a like replacement (which would probably be a rebuilt motor I'm guessing). At best, I'm thinking they might cover $400 or so. I've been looking into VS pumps, and with a 14k-ish gallon pool and no water features (1 skimmer, 1 suction cleaner, 3 return jets... that's it) I know I don't need a monster pump, but I've seen quite a few things saying the "right sized" smaller HP VS pumps aren't a good choice. They're nearly the same price as their full power brothers and they would have to run much higher power to keep up, whereas a larger pump can run at a much lower speed to get the water flow that I need.
I saw another post on here, because I had the same question, about how I could "encourage" this pump to die so I can replace it. If I had to pay a $800 or so upcharge/delta to get a VS installed and have the warranty cover $400 or whatever amount they'll cover, I think it's a win/win. Their contractor gets work and I get a VS pump and its benefits. I understand the arguments about whether it's ethical or not, but I don't think it's hurting anyone if this pump should suddenly find itself on the losing end of some "random" event that caused its demise. Any suggestions are welcome.
So, to the original question -- is the likely culprit with my lower-than-normal PSI a failing pump, or should I be looking elsewhere?
Thanks and sorry for the long post!