How High For Pool Valves?

[Quarterwave]

Hi everyone,

I've been reworking some of the plumbing to my pool - the previous owner installed 3 valves about an inch from the ground, which prevented one of the valves from being able to be opened all the way.

So, in my infinite wisdom, I cut the pipes, and moved all 3 valves about 3 feet off the ground.

My issue, is that the pump (Hayward Max-Flo XL) now has issues priming - to the point where is just won't - even if I pre-fill the basket with water etc...

Did I place the valves too high?

I can also see a lot of cavitation in the basket of the pump (through the looking glass) - and aside from a small drip in the return pipe, there are no visible leaks. I also checked the little o-ring in the joint which attached the pipe to the pump, and it is seated correctly.

Any help is appreciated.

 

[mikemass]

The valves you raised? Are they suction side or return side? It sounds like you caused a suction side leak somewhere. if this work you did was suction side, when you turn off your pump does anything "spit" water anywhere on the suction side?

The "small drip" in the return pipe should not cause the cavitation in the basket, but should be addressed at some point.

Pics would help too.

 

[Quarterwave]

Hi Mike,

Sorry - no pics @ the moment - I'm at work.

The valves are on the suction side. When I turn the water off, there is no "spit" of any water. My concern is that the pipes might be too high (they are about 3 feet off the ground and there are 3 valves) although when I can get the system primed, it pumps great.

 

[duraleigh]

Pics would help but I agree with mikemass, I think your issue is a suction side leak. Does ALL the air go out of the pump filter basket after the pump rimes?

 

[Quarterwave]

Yeah, sorry - I'll try to get the wife to take some for me.

In regards to all the air going out of the filter basket - I would say yes - but only sometimes. There is usually often small air bubbles in there - which increases over time.... it has been like that for 2+ years.

 

[mikemass]

No Spit of water is promising. The issue may not be the height of the valves in relation to the ground, but the height in relation to the surface of the pool.

Being that you didn't have a priming issue prior, I am going to make an assumption that you have a flooded system (Pool equipment below the surface of the pool). Please tell me if that is incorrect.

But now raising the valves 3 ft up, I have a feeling that the valves are now above the surface of the pool, but the pump basket is still below (again correct if wrong).

Now IF your system is 100% completely enclosed... and I mean absolutely ZERO introduction of air anywhere in the system, the height should not make a difference. But if you have a leak anywhere (in your case the small drip in the return line) air will get introduced to the system and find it's way to a high point of the system. We like that highest point to be the air escape valve on top of the filter, but now I have a feeling that your new set up has the 3 suction valves quite high.

Once those get full of air and you kick the pump back on, it has to first suck all of that air out of those raised pipes. Without seeing your system, I believe this is what is going on.

Do you have a valve before the return side leak, so you can turn off that return for a test? If so, shut that down, (assuming you can return elsewhere), run your pump (get it to prime however you've been doing). Once it is fully primed shut it down and leave it off for a good 30 mins to an hour to see if air gets introduced again. Fire up pump and see if it held it's prime. If so, the return side leak is introducing air into the system while pump is off. If no prime again, we have to dig deeper.

I know I made a lot of assumptions about your set-up, so clarify where I may be right or wrong.

 

[Quarterwave]

Pics of plumbing.

 

[duraleigh]

My bet is on a leak. Check that 90 just before the pipe drops back down.....it looks crooked. couple below middle valve looks a little shaky, too.

If you have ANY air in the pump basket when the pump is running, you are sucking air and that is probably what's preventing you from being able to prime easily.

 

[Quarterwave]

Okay thanks - I was working with the existing plumbing and had to patch things together. Do you think the valves are too high?

- - - Updated - - -

Thanks Mike - very helpful information. I think I'll need to take a day off tomorrow and rework things. The return side leak is coming at a connection that goes into a circular type of device with 4 pipes leading out of it (it's hard to see in the image, but it's just to the right of the third pipe from the left in the image)... and I can't find any information about it online. My guess is that it's something to do with the spa?

Anyway, whoever installed it before made a crappy joint and it slowly drips from there. Can I use outdoor caulking or pool leak sealer to fix? As there is literally no room between the unit and the pipe to cut and insert a sleeve.

 

[WASP]

If it was mine I would lower the suction piping so you have the minimum height above the water level. Less suction head to overcome when priming. You can use silicon chalking around you glue joints to seal any possible leak paths. Not the ideal fix but may help you isolate the problem. When I replaced my pump I machined some internal pipe sleeves, couplings, since there was no room to use an external pipe coupling. I'm not aware of any that are available off the shelf. Perhaps a plumber can chime in. With the internal sleeves, I did not have to replace the expensive Jandy valves.