pump losing pressure - help me troubleshoot. please.

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D

DrThop

0
Jul 5, 2017
16
THE WOODLANDS
Pool Size
15000
Surface
Plaster
Chlorine
Liquid Chlorine
Hello there,

I have a 15000 gal. in ground pool. I am in the process of getting it ready for spring and summer, but I am facing a bit of a problem with my main pump. I have a WhisperFlo WF28 C, and a Pentair Clean and Clear Plus cartridge filter.

over the winter here in the Houston area we had a few overnight freezes, and I noticed that water was leaking from the top of the pump (exit) so I changed the piping coming out of it. At the time I also changed the gasket that seals motor, and the o-ring that goes in the diffuser.

I cleaned the filters last weekend the gauge on the filter was about 25 psi, and then when I turned it on the pump went from 14 psi to about 5-6 psi in about about half an hour and there was a noise as if it was sucking air.

In the last few days I've changed the o-ring that goes in the filter cover, and again the gasket and o-ring I mentioned previously.

There is a Jandy valve right before the pump, I also changed all o-rings in it (three).

after all the changes, I turned it on and it worked for a bit, it had good pressure, but within about half an hour it lost pressure again, this time it went from 14 psi to about 8-9. I'm at a loss on what to do.

Any suggestions will be appreciated.

best.

Dr. Thop.
 
Re: pump losing pressure - help me troubleshoot. please.

Dr,

Forget about the filter PSI, for a minute, and tell me what the return flow feels like going back to the pool? Does the return flow feel any different when the pressure is high vs. when the pressure is low??

Is the pump basket filled with air bubbles?

Are bubbles coming out of your pool returns?

If you slowly run water from a garden hose over the pump plumbing does it have any effect on the noise or the pressure?

Thanks for posting,

Jim R.
 
Re: pump losing pressure - help me troubleshoot. please.

Hi Jim,

Thanks for your message. here are the answers to your questions:

The return flow is very weak, I'd say about 10-20% of what it normally is. I can plug any of the jets easily without any effort. I know you said to forget about the pressure, but now the pressure is always low, I don't get any initial build up anymore. steady about 7-8 psi.

No bubbles in the basket.

Yes to bubbles coming out of the pump returns.

I did what you suggested, and ran water over the piping, and the pump. there was a very slight change of pitch on the noise when I pointed the garden to the area where the motor joins the housing. Could that mean that the gasket is poorly installed? not tight enough? I had never replaced one of those before, but it didn't seem like a big deal.

Cracked housing? time to call someone to look at it?

Thanks,

T
 
Re: pump losing pressure - help me troubleshoot. please.

Dr,

I was hoping it was a bad gauge caused by the freezing weather...

Let me see if I can get one of our pump experts to chime in...

Thanks,

Jim R.
 
Re: pump losing pressure - help me troubleshoot. please.

Your symptoms indicate a restriction on the suction side of your system. Somewhere between the skimmer(s) and the pump, the flow appears to be partially clogged.

Perhaps you can run a "snake" through the suction side from the pump basket.....feeling for obstacles. The lower pressure always indicates your problem is on the suction side.....no point to look anywhere else.
 
Re: pump losing pressure - help me troubleshoot. please.

I second the suction line problem. There is something blocking the flow/air getting into the pump suction line.

Make sure the water level in the pool is high enough and you aren't sucking air thru the skimmer itself before you do anything else.

Then start looking deeper into the whole suction line.
 
Re: pump losing pressure - help me troubleshoot. please.

The output was leaking. That usually means that the pump ran dry and the water got hot.

If the water got hot enough to warp the threaded fitting coming out of the pump, it got warm enough to warp the threaded fitting going into the pump.

You probably have an air leak at the threads going into the pump.

Is the pump basket deformed?

Try having someone turn the pump on and off while you look closely at the fitting going into the pump. Don't do on/off too fast. Wait at least 10 seconds between on/off.

Turn the pump on and let it get going, then turn it off. If it's leaking, it should squirt out some water.

If it's leaking, you should be able to tell.

Also, look under the pump while it's running to see if it's leaking.

Did you install the impeller screw with the little O-ring? If not, you might be getting air sucked in at the eye of the impeller.
 
Re: pump losing pressure - help me troubleshoot. please.

Well the news is not very good. The problem is still there. Here is a run down of what has happened over the last month.

After changing the piping coming out of the pump, the o-rings for the pump and the Jandy valve, I kind of gave up and called my home warranty service. They sent a company that changed the motor (I wasn't there so no idea why). the issue with the pressure persisted. And as before small bubbles come out of the jet closer to the pump.

I complained and they sent another company out, this time I was there, and they pointed that It could be a blockage on the incoming piping. the guy used a rubber bladder to shoot water into the pipe while plugging one of the skimmers each time. Nothing came out of the pipes. he said it could have been air trapped in the line (?). the pressure was good for a few hours but it dropped again.

I got a plumber to come out and he used an air snake on the line, but that didn't have any effect, he was afraid of using to much pressure because he could burst a pipe. He was at a loss. but suggested to have a leak detection company come out, I am not sure if a $325 diagnosis is worth it, I don't see the ground wet around the pool, the water level is not dropping.

I changed last night the pipe coming into the pump from the Jandy valve. No positive results. Still the pressure was around 10 (should have been about 12-14) and then later dropped a bit (8)

I even called Leslie's to see if they could send a technician (I can hear your collective gasp), but after explaining the situation, they declined to help, maybe that is a good thing.

Is there anything short of tearing up the ground and replacing the piping that I should do? all ideas are welcomed.

Best

DrThop
 

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Dr.

Definitely sounds like air intrusion. Here's what I'd do next. Start the fittings furthest from the pump and use a water hose to cover each potential leak. If you notice a change in the sound of the pump or reduction in bubbles in the discharge then you've found your leak. Most likely this will be a screwed fitting, or a bad gasket. Could also be a hairline crack in the basket strainer. Work all the up to the pump and any connections on the suction side including the basked and it's lid. If this doesn't find the leak check very carefully again. You get better at this technique as you go and you may find something 2nd pass. Here is a 2 min video of the technique. If this doesn't help try replacing the pump seal assembly, not just the o-ring. Do you notice any water leaking from under the pump assembly?

I hope this is helpful.

Chris
 
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