Colder weather & air under pump lid

yp93

Member
May 23, 2024
18
Austin, TX
Pool Size
6855
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-3)
Hi All!

Tried to search the forum but found only one thread, so will ask just in case.

Texas, weather doesn’t get too cold, so not closing the pool. It is roughly 45-50 during night and 60-70 during the day.

So the pump seemed to have some air in after the night. This never happened during warmer seasons, unless skimmer basket was clogged or any of the other common reasons.

The only 2 things different now is that weather is colder and pump runs 24/7 as I was traveling and didn’t want to risk it to hit freezing temperatures while I am out, so it doesn’t re-prime every morning. Turning off the pump - it doesn’t lose prime.

So the question is - is there anything that cold weather might be doing that impacts this? Should I set timers with a few minute gap to actually stop and re-prime? Lid seals are 100% clean as I check them every time but I didn’t lube it, so could it be that or cold weather has some impact for real?

Thanks!
 
Lubricate the o-rings. Use silicone lubricant like magic lube II. Don't use Teflon/PTFE lube.

Yes, set a gap in your timer and re-prime once a day.

Is it a VSP? What RPM setting are you using?
 
Lubricate the o-rings. Use silicone lubricant like magic lube II. Don't use Teflon/PTFE lube.

Yes, set a gap in your timer and re-prime once a day.

Is it a VSP? What RPM setting are you using?
Yes, it is VSP. 1725RPM (default speed on Hayward one).

Is it expected to happen in cold weather though? Basically - if issue is in O-Ring, lube should fix it altogether or re-priming is still required?
 
Lube it and see. If you still get air, the continue re-priming. Even in summer, mine is set to reprime every 24 hours.

With colder weather the o-ring is less compliant. VSP tend to get air at low speed.

From my experience, there are two ways that air can get into a pump basket at low speed.

1) On low speed, pump basket lids sometimes do not seal as well as high speed because of the design.

2) The pump basket is under lower pressure than atmospheric pressure which forces dissolved gases to come out of solution. However, this usually takes much longer than #1 to occur (hours vs minutes).
 
Lube it and see. If you still get air, the continue re-priming. Even in summer, mine is set to reprime every 24 hours.

With colder weather the o-ring is less compliant. VSP tend to get air at low speed.

From my experience, there are two ways that air can get into a pump basket at low speed.

1) On low speed, pump basket lids sometimes do not seal as well as high speed because of the design.

2) The pump basket is under lower pressure than atmospheric pressure which forces dissolved gases to come out of solution. However, this usually takes much longer than #1 to occur (hours vs minutes).
Thank you! Yeah, it doesn’t happen immediately for me at all. When it was re-priming every morning - it was enough to hold prime till end of day (it starts at 7am and turns off around 9pm). I set up the second overlapping timer yesterday around 4PM (so it was running for 9hrs already at that point) and there was no air. So air appeared overnight, basically, which is why I thought it has something to do with cold
 
So the question is - is there anything that cold weather might be doing that impacts this?

The Space Shuttle Challenger was destroyed in 1986 due to primary and secondary O rings that shrunk when it was launched in cold weather.

O rings develop leaks when the temperature drops.
 
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Yes, it is VSP. 1725RPM (default speed on Hayward one).

Is it expected to happen in cold weather though? Basically - if issue is in O-Ring, lube should fix it altogether or re-priming is still required?
Is this a Hayward TriStar VSP? If so, it is not unusual for there to appear to be air in the pot at lower speeds. Mine virtually never completely fills and of the many I have installed, only one or two ever filled completely, even the original single-speed models. Check to see if you can continually release air from the filter. Likely, no.
 
Is this a Hayward TriStar VSP? If so, it is not unusual for there to appear to be air in the pot at lower speeds. Mine virtually never completely fills and of the many I have installed, only one or two ever filled completely, even the original single-speed models. Check to see if you can continually release air from the filter. Likely, no.
It is TriStar, yes. But it also filled up to the top no problem previously. I can release air until water starts going from the filter.

Why does it catch air though? Is it this pump’s known problem of some sort?
 

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It is TriStar, yes. But it also filled up to the top no problem previously. I can release air until water starts going from the filter.

Why does it catch air though? Is it this pump’s known problem of some sort?
The vast majority of pool filtration systems are not "air tight." Sooner or later very small leaks that will allow air into the system when it is off, but not large enough to leak water, will occur. That allows the water in the filter to drop and air into the system. When the pump starts the air is expelled or sits above the air screen in a filter and does nothing to reduce the filtration. It can be released through the outside air release until water comes out, but will return when the system shuts down. Its not an issue or anything "wrong," just how pools seem to work after a while.

As has been mentioned, in cold weather the O rings likely shrink a bit to add to the area that can let air into a system.

TriStar pumps were the first pumps I installed that did not appear to fill completely. At first I thought it was an installation issue, then maybe a pump issue, but found it to be normal for the brand. Sometimes they would and others, not. On occasion, even mine will, but most of the time no, and never on the lower speeds. I know it isn't an air/suction leak as I can release the air from my filter, come back an hour or more later, open the valve and only water comes out, so no continuous air into the system. You will see comments on this forum from many users of VSPs, regardless of brand, that have the same question, "Why is there air in my pump at the low speeds?" Seems to be a "normal" experience with them. Has been for my customers.
 
Instead of re-priming, increase the rpm to 2800 or so for15 minutes twice daily. The higher rpm should easily purge the air out of the pump basket area.

A little air in the pump basket is normal in a VS pump running at lower rpm.

You may find you can run at a lower rpm while still keeping the SWG flow switch happy and getting adequate skimming. Going to a high rpm for 15-ish minutes once ot twice daily will purge any bubbles in the pump basket area.
 
Instead of re-priming, increase the rpm to 2800 or so for15 minutes twice daily. The higher rpm should easily purge the air out of the pump basket area.

A little air in the pump basket is normal in a VS pump running at lower rpm.

You may find you can run at a lower rpm while still keeping the SWG flow switch happy and getting adequate skimming. Going to a high rpm for 15-ish minutes once ot twice daily will purge any bubbles in the pump basket area.
Thank you! Done it all now, will see if it helps 👍
 
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