Can't get prime. Could the dying motor be why?

[Kelly Gordon]

We opened our pool two weeks ago. Got everything up and running at the beginning, although the pump was really loud. I figured the motor is dying. So I closed our line valves and turned off the pump, so we could sleep at night. (The pump is right next to our bedroom window.)

Enter this week. Our pool is close to overflowing from storms last week. Water is getting cloudy, even though it's still relatively cool in Minnesota. I'd like to turn the pump on during the day to start to balance the water (and turn it off at night because sleep), but now I can't get prime. I've tried to back-fill one line, I've filled the pump pot to overflowing several times, basket is tight. But when I flip the pump switch, the water drops and no new water comes in (but the motor sounds ever more loud and funky). I've given it as much as 90 seconds, but with no new water flowing, and the motor grinding away, I opt to turn it off at that point. (Water then flows back into the pump basket area, not quite to filling, but up to the where the lines come in.)

Questions:
1. Could a dying motor affect my ability to get prime?
2. Is there a way to know if my pump is also going bad? I'm trying to figure out what I need to replace.
3. Is there something I could do to get prime that I haven't already tried.

FWIW: My pump is a full story above my pool and on the other side of the house, so the water has to travel quite a ways. I know it can take a while to get prime, but I've worked for hours and I haven't seen so much as a trickle coming in to the pump pot. I felt in just now and the impeller seems to be fine; it's in once piece, no obstructions.

 

[SoCalGuy]

We have a similar set up... our equipment is about 10 feet above the pool... and we fought a loss of prime with our old pump for years. Same drill as you… fill the basket, run pump, water disappears, shut off the pump, water returns to basket, refill basket, run pump, etc. etc. etc. until it would finally prime.

Having the equipment that far above the water level is a lot of work for a pump even with equipment in perfect condition. And the slightest air leak - on either the suction or return side - will make it almost impossible to keep it primed.

The increasing noise is a good indicator that your pump is about to bite the dust. That's what eventually what happened us.

We replaced our 1.5 HP Whisperflo with a 3HP Intelliflo and no more prime issues. The extra hp really helps... plus it's substantially cheaper to run.

In the meantime, make sure your check valves are sealing and don't have debris stuck in them. And make sure the unions going into and out of he pump are REALLY snug.

Good luck.

 

[Kelly Gordon]

Thanks for the tips, SoCalGuy. (We used to live in San Diego.) I would guess our pump is 15' above the pool, so yes, even when all the equipment is working perfectly, it's a haul.

Since the pump was working when we first opened, I don't think there's an air leak anywhere. But the motor is definitely worse by the hour, so if that powers the suction, it's possible I'm just not getting enough juice to pull the water straight up.

If we replace the whole pump set-up (versus just replacing the motor), we're thinking about putting in a variable speed pump. Not sure if that would help us with the prime issues we've always had. The pool guys who would be doing the install are very aware of the peculiarities of our set-up, so I will be sure to ask what we can do to make it easier.

 

[Kelly Gordon]

An update on this: I plugged my skimmers today with gizmos, opened all my lines (1 main, 2 skimmers but I don't know which line is which because they aren't labeled), backfilled the lines with water for 10 minutes, let the pump run for 4 minutes and I still couldn't achieve prime. I didn't even get a trickle of water coming from the lines. (Although water did flow back into the pump pot after I turned off the pump.)

The pump/motor is making a really loud noise and the sound is inconsistent. It definitely feels like the motor is dying, but it's not dead yet. So someone reconfirm for me, so I can make sure I understand: would a dying motor not provide enough horsepower for a pump to achieve prime? Or does the fact that I can't get prime, even under these circumstances, mean the pump is going bad too? Or is something more nefarious going on? (The whole system worked fine two weeks ago, so I don't think there's a leak in the pipes, but you tell me if the signs point to that.)

My pool has been without a pump for 10 days now and is starting to turn pretty green, so if I need a complete new pump, I need to get on it.

 

[SoCalGuy]

You said the last time the pump was working it was loud, so you "closed our line valves" and turned off the pump. Just to confirm, you did re-open the suction valve(s) to the pump, right?

As for whether you can get away with just replacing the motor or whether you should get a whole new pump, that's a tough call over the interwebs. How old is the pump? How many HP? You should talk your pool guys, but if it was me (it actually WAS me about 6 months ago) I'd get a new pump. The rebate plus the energy saving made it a pretty easy decision.

If you do decide on a new pump check the specs. You need a workhorse for your setup. 15' is a lot of elevation and 30k gals is a lot of water. I think our Intelliflo manual says not to install the pump more than 10' above the water, so definitely talk to your pool guys and have them confirm whatever pump you get will do the job.

Good luck.

 

[Kelly Gordon]

Thanks SoCal. The pump was installed in 2011. One possible factor that could have led to an earlier demise: it lives outside in the winter, which is no small thing in Minnesota. I assume it's possible our extreme weather might have shortened its life?

And yes, the suction valves are what I refer to as water valves. Those are the only ones I've messed with during this process. (These are the lines bringing water from the pool, to the pump, right?)

Thanks for your help. I'm pretty sure our pool guys have recommended a variable speed Intelliflo.

 

[SoCalGuy]

I think you'll be happy with the Intelliflo. Under 2000rpm you can barely hear it. Super efficient too. Filter seems to work better. I think the extra HP really helps when you have a big elevation climb.

Cheers!