Do I need a check valve?

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D

dcaton

Well-known member
Jun 7, 2019
58
Ft. Pierce, FL
Pool Size
11000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-30 Plus
Perhaps a dumb question, but can't hurt to ask.

New (to us) house, built in 1992. Water bubbles coming out the returns. Existing valves are Jandy, I believe non-positive, They were dry as a bone so I replaced the o-rings and broken grease cups. Also cleaned and lubed the pump and filter o-rings. That stopped the air bubbles for a while, now they're back.

We were away for a few days, and the pump lost its prime. (surprisingly, it seems undamaged). There are no obvious cracks in the pipes or valve bodies. Clearly there is an air leak somewhere, so I'm going to re-plumb the whole system with new valves and a new larger cartridge filter. Pump is a 1.5hp Intelliflow VS

My question is, should I put a check valve in front of the pump's intake? I realize that in a properly functioning system with no air leaks the pump should not lose its prime and a check valve should be unnecessary. But is there any downside? We are away a lot in the summer, and if something goes wrong and there's no water flow then the SWG can't do its job and I don't want to come back to a green pool. It's just a pool, no spa and no heater (yet).

Bonus question, why are there positive and non-positive valve types? Why would you not want a positive seal?
 
Last edited:
YippeeSkippy said:
Any air viewed in the pump basket? Sometimes the lid to the pump basket needs a bit of lube to seal it which could help with the air in the lines coming out the returns.
Click to expand...
I cleaned and lubed the basket lid o-ring when I rebuilt the valves. At low speeds there's some air (which I understand is normal), at high speeds, no.
 
d,

Does your pump shut off each day?? If so, I would set it to run 24/7, at a low RPM, while you are gone. Or all the time. I run my IntelliFlo at 1200 RPM, 24/7 for less than $20 bucks a month.

Do you really have a 1.5 HP IntelliFlo pump? 99% of them are 3 HP, they do make a smaller one, but they are a little unusual to find. Show us a pic..

Thanks,

Jim R.
 
dcaton said:
Perhaps a dumb question, but can't hurt to ask.

New (to us) house, built in 1992. Water bubbles coming out the returns. Existing valves are Jandy, I believe non-positive, They were dry as a bone so I replaced the o-rings and broken grease cups. Also cleaned and lubed the pump and filter o-rings. That stopped the air bubbles for a while, now they're back.

We were away for a few days, and the pump lost its prime. (surprisingly, it seems undamaged). There are no obvious cracks in the pipes or valve bodies. Clearly there is an air leak somewhere, so I'm going to re-plumb the whole system with new valves and a new larger cartridge filter. Pump is a 1.5hp Intelliflow VS

My question is, should I put a check valve in front of the pump's intake? I realize that in a properly functioning system with no air leaks the pump should not lose its prime and a check valve should be unnecessary. But is there any downside? We are away a lot in the summer, and if something goes wrong and there's no water flow then the SWG can't do its job and I don't want to come back to a green pool. It's just a pool, no spa and no heater (yet).

Bonus question, why are there positive and non-positive valve types? Why would you not want a positive seal?
Click to expand...
What is a non-positive Jandy valve? Are they labeled as such? Never seen one. Is the actual seal that shoukd be around the perimeter of the diverter missing. On old valve they were replaceable and may have worn out (you said it was dry) or been removed. New Jandy valves are "Never Lube." You may need new diverters.

Valves old enough to still have the grease cup (done away with about 30 years ago) are likely to have not just a worn stem and O rings, but also the lid socket where the stem goes through can be worn. On those old valves you can remove the O rings from the stem, grease the stem, replace the O rings and put a layer of grease on them, then about 3-4 wraps of Teflon tape and more lube on that then reinstall. Has solved that problem on many pools for me. More than one valve in front of the pump? Do the same to all.
 
Jimrahbe said:
d,

Does your pump shut off each day?? If so, I would set it to run 24/7, at a low RPM, while you are gone. Or all the time. I run my IntelliFlo at 1200 RPM, 24/7 for less than $20 bucks a month.

Do you really have a 1.5 HP IntelliFlo pump? 99% of them are 3 HP, they do make a smaller one, but they are a little unusual to find. Show us a pic..

Thanks,

Jim R.
Click to expand...
Sorry, no it's a Superflow. Yes, it shuts off. I'm using the default schedule, which I believe runs 12 hours.

I suppose I could (or should) run it 24/7 when we're gone, but clearly there's a leak somewhere and it's going to bug me until I fix it.
 
1poolman1 said:
What is a non-positive Jandy valve? Are they labeled as such? Never seen one. Is the actual seal that shoukd be around the perimeter of the diverter missing. On old valve they were replaceable and may have worn out (you said it was dry) or been removed. New Jandy valves are "Never Lube." You may need new diverters.

Valves old enough to still have the grease cup (done away with about 30 years ago) are likely to have not just a worn stem and O rings, but also the lid socket where the stem goes through can be worn. On those old valves you can remove the O rings from the stem, grease the stem, replace the O rings and put a layer of grease on them, then about 3-4 wraps of Teflon tape and more lube on that then reinstall. Has solved that problem on many pools for me. More than one valve in front of the pump? Do the same to all.
Click to expand...
Apparently its a valve that doesn't completely shut off the flow. Maybe obsolete, I don't know. If the valves with grease cups were done away with 30 years ago, then these are definitely the original valves. I'm just going to replace them.
 
The question remains though: is there any reason to have a check valve? Relatively cheap insurance against some future problem, or a waste of time and money?
 

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JamesW said:
They are used for solar to allow the panels to drain.

What model number is on the valve?

I would put a check valve after the pump and not in front of the pump.
Click to expand...
Ah, yes. Along time ago, when Jandy valves were used as solar valves, the instructions were to remove the seal. The diverter had 2 screws that held a panel in place that held the seal. Usually, we'd just drill a 1/4" hole in the diverter. Man that was a long time ago. I never saw one available from distribution in that configuration. Easier to just have one item that could be changed, I guess. Compool/Pentair had solar valves with a small check valve built in to the diverter. Had to order them or get one in the solar control kit.
 
JamesW said:
I would put a check valve after the pump and not in front of the pump.
Click to expand...
On the outlet side? That wouldn't prevent the water from draining out of the pump and back into the pool, if there was a leak in the intake side, or perhaps a bad seal on the pump basket lid.
 
JamesW said:
If you have a suction side air leak, the pump is not going to prime anyway.
Click to expand...
If I have air bubbles coming out the returns I've got to have a suction side air leak, right? A leak in the pressure side would be evident as water would be shooting out at the faulty joint, valve or whatever (assuming the leak was aboveground).

Sometimes the pump will eventually prime on its own, but if not, filling up the bowl with water is usually enough to get it to prime. Hence, my thought of putting a check valve on the suction side to prevent the bowl from draining back into the pool.

Obviously, the system needs to be airtight. I hope to rectify that by replacing the old jandy valves, as well as the o-rings on the pump unions and bowl cover. I just thought that if I'm redoing the plumbing this would be the time to add a check valve if it made sense to do so.
 
dcaton said:
If I have air bubbles coming out the returns I've got to have a suction side air leak, right?
Click to expand...
Usually.
dcaton said:
A leak in the pressure side would be evident as water would be shooting out at the faulty joint, valve or whatever (assuming the leak was aboveground).
Click to expand...
Usually.

You can use a check valve on the suction side if you want.

I would not use a check valve on the suction side, but that is my personal opinion.

You should do whatever you feel is best for your situation.
 
JamesW said:
Usually.

Usually.

You can use a check valve on the suction side if you want.

I would not use a check valve on the suction side, but that is my personal opinion.

You should do whatever you feel is best for your situation.
Click to expand...
It's your opinion because...?

I know I can do what I want. I asked here because I'm not sure what is best and looking for advice. Not just do or don't, but the rationale behind the advice.

The sprinkler system at my last two houses uses well water, and both have a check valve on the intake side of the pump, presumably to help keep the pump primed. I think that's where my initial thought of adding a check valve to the pool pump came from.
 
1) Pumps are designed for pressure, not suction.

For suction, you have about 17 feet of head loss available to use and the return has about 75 feet of head loss available.

So, I always prefer to avoid putting head loss on the suction side.

2) The return side water is strained by the pump basket, so there is less likely to be large debris that can clog a check valve.

3) Restrictions on the suction side create more vacuum, so an air leak will be made worse by a check valve or any restriction.
 
JamesW said:
1) Pumps are designed for pressure, not suction.

For suction, you have about 17 feet of head loss available to use and the return has about 75 feet of head loss available.

So, I always prefer to avoid putting head loss on the suction side.

2) The return side water is strained by the pump basket, so there is less likely to be large debris that can clog a check valve.

3) Restrictions on the suction side create more vacuum, so an air leak will be made worse by a check valve or any restriction.
Click to expand...
Ok, thank you! So given this, does a check valve on the pressure side make any sense at all?
 
dcaton said:
So given this, does a check valve on the pressure side make any sense at all?
Click to expand...
I prefer to have a check valve after the pump, especially when:

1) The pump is above the pool.
2) The filter is a DE filter.
3) To help prevent decompression backflow if air gets trapped in the filter.
4) To prevent dirt backflow when the pump is off if the return side has an air leak.
 
JamesW said:
I prefer to have a check valve after the pump, especially when:

1) The pump is above the pool.
2) The filter is a DE filter.
3) To help prevent decompression backflow if air gets trapped in the filter.
4) To prevent dirt backflow when the pump is off if the return side has an air leak.
Click to expand...
Thank you again. The pump is above the pool, filter is (will be) a new 200 sq in cartridge filter.
 
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