Pump losing prime after being turned off

[gmason86]

Hi all,

Need some help please!

When I turn off my pump, it loses prime. My pump is quite far from my pool, and probably several feet above the water. However, I gather this shouldn't be a problem and it ultimately means I likely have an air leak on the suction side, ie somewhere between the skimmer and the pump itself.

I've gone through a few of the suggestions I've seen on here:
- Replaced O-ring on pump, cleaned lid and used a silicone lubricant from the pool shop
- Used Teflon tape around the drain plugs to help the seal
- Ensured pump lid is tight

I tried putting foaming hand soap (couldn't find shaving foam!) around the lid and drain plugs and didn't see anything obvious.

I listened for an air leak around the pump, but the noise of the water rushing away was too loud. If anything, there may have been some noise from the filter but that's obviously not on the suction side. That's another problem, I guess. But not my immediate problem.

I tried closing the valve before the pump after I switched off the pump. This seemed to stop the water rushing away after it was closed, aside from the amount that managed to disappear before I could close the valve. This suggests to me that the air leak must be after the valve, ie around the pump itself, presumably either the lid or the drain plugs. Does that sound right?

If that's the case, any thoughts on how to proceed with figuring this one out? I'm not too sure where to go next and how to do it, but obviously this needs fixed...

This is a system I inherited when we moved into the house, so my knowledge is limited.

Help please

Thanks!

Graham.

 

[borjis]

what about the union o-ring coming into the pump basket?

Is it in good condition? did you lube that?

I had that exact pump at my first house/pool and had a suction side leak
(would not hold prime overnight) and I recall loosening the union
taking out the o-ring, inspecting it and putting it back in place with
a bit of lube then it held just fine.

Another thought is that it could be leaking air from that valve with the blue handle.
It's odd to me that someone would put a valve on an incoming line like that,
But I also have one at my current home/pool (came that way when I bought the place)

Just thinking out loud:
And last I can't help but think it might possibly be all those flex hoses with clamps.
Unions and pvc pipe would potentially deal with any kind of leaking those might be
causing. Yes they are on the pressure side so if they were the cause you would
probably have water drips too when the pump is running. so not likely those.

 

[gmason86]

what about the union o-ring coming into the pump basket?

Is it in good condition? did you lube that?

I had that exact pump at my first house/pool and had a suction side leak
(would not hold prime overnight) and I recall loosening the union
taking out the o-ring, inspecting it and putting it back in place with
a bit of lube then it held just fine.

Another thought is that it could be leaking air from that valve with the blue handle.
It's odd to me that someone would put a valve on an incoming line like that,
But I also have one at my current home/pool (came that way when I bought the place)

Just thinking out loud:
And last I can't help but think it might possibly be all those flex hoses with clamps.
Unions and pvc pipe would potentially deal with any kind of leaking those might be
causing. Yes they are on the pressure side so if they were the cause you would
probably have water drips too when the pump is running. so not likely those.

Excuse my ignorance (I'm new to this!), but what's the union o ring coming into the pump basket? Can you perhaps highlight what you mean on my image? Or describe it? Sorry!

As for the flex hoses, I totally agree it'd be nice to be rid of them! But there doesn't appear to be any leaks and I'd rather avoid taking things apart that somehow don't leak.


I half wondered if perhaps the pump is worth replacing with a variable speed one...

Thanks!

Graham

 

[gmason86]

I'm assuming you mean this section that I've drawn the red circle around?

So do I just loosen that, open it up, check if the o-ring inside is in suitable condition and lube it if it is? Does the o-ring sit inside the pump?

As far as the valve being there, I'm assuming it's there so you can close it when opening the pump basket to clean it, without having all the water disappear. But that's just a guess.

Any thoughts on whether I'm better just replacing the pump (no idea how old it is???) and perhaps the filter too (again, no idea how old it is???)? I've seen the pentair intelliflow mentioned.

 

[borjis]

The pump itself is probably fine. I don't know your electric rate but where I live a vs offers little savings over a single speed.

Yes what you circled, but the closeup looks like it is a glued in fitting, not a union.

One thing you could try. Make sure the power to the pump is off so it cannot come on, then close that blue handled
valve. If you still lose prime over night, then It's likely to be the valve or the fitting coming into the pump leaking air
as far as I can tell.

When did it start losing prime?

 

[gmason86]

The pump itself is probably fine. I don't know your electric rate but where I live a vs offers little savings over a single speed.

Yes what you circled, but the closeup looks like it is a glued in fitting, not a union.

One thing you could try. Make sure the power to the pump is off so it cannot come on, then close that blue handled
valve. If you still lose prime over night, then It's likely to be the valve or the fitting coming into the pump leaking air
as far as I can tell.

When did it start losing prime?

In what circumstances do you normally see savings using a VS pump? I live in Ontario and our electricity rates are notoriously high! Does that make a saving more likely? On that note, I read the pentair intelliflo ones run off 230V in most circumstances. How do I know what my current one runs off? The pump itself says 115/230, presumably meaning it can do either. The circuit breaker is a double switch, with a 20 on both. Not sure if that helps me figure that one out...

Yep, you're right about it being glued. I had a closer look and unfortunately it is glued.

I had that valve closed overnight, then turned it back on at lunch. Water flowed right in immediately, so I guess that rules out the valve causing any issues and it therefore presumably must be the pump lid or drain plugs (or the pump itself!). Does that sound right?

As for when did it start... Well, don't judge, but I think it was doing this all last season Someone had advised me that it was normal because the pump is at a higher level than the pool water. Having read more this year, it certainly isn't normal and the pump probably isn't best pleased at me doing that. So I can't pinpoint exactly when/how it happened. But... I'm learning thanks to here!

Thanks!

 

[borjis]

I'm not very knowledgeable about vs compared to single or 2-speed for savings, but it sounds like a vs might save some money.
A lot of power companies also offer a rebate if you go vs. not sure sure what they do in Ontario (Canada or California?)

Sounds like it is 220v but should confirm to avoid damage or malfunction if you get a vs.
You can take the end cover off the pump motor to determine if it is wired 220 or 110. maybe post a photo.

Ya not normal to ever lose prime. definitely suction leak. Pump seals seem to go out quicker if it has to prime itself every day.

ok so it hold prime just fine if the valve is closed? hmmmm....when it's off after running, can you get your head down near
the basket and hear any low hiss noises from air escaping?

Hopefully others will chime in with ideas. I only had that union seal not seated right so it was easy to fix.

 

[gmason86]

Haha, I didn't even realize there was also an Ontario in California. I should have guessed there would be another somewhere. Since moving to Canada in 2012 (from Scotland), I've found that North America likes to recycle names an awful lot! I'm in Canada


Will I be able to hear the hissing when the valve is closed, given the water doesn't run away at that point? It's very noisy when I open the valve with all the water rushing away, so it's hard to pinpoint anything then. I can absolutely try out listening when the valve is closed and everything is off, but I was assuming I wouldn't likely hear anything then as the valve is closed so the water isn't being pulled away.


Out of interest, can you tell from my pics if my suction piping is 1.5 inch or 2 inch? If I go down the route of replacing the pump (now or in the future), I gather the superflo is generally better suited for older systems with 1.5 inch piping. I know I can go measure it when I'm home, but just wondered if it's obvious to you just from looking? Regarding the rebate, my utility company unfortunately don't offer one. However, I did call them and they said they have something in the works but needs approval from the independent electric authority and probably won't be in place until a few months from now.


Thanks!