Pump Loses Prime Every Night

h2o

Well-known member
Jun 30, 2008
68
Houston, TX
I have been noticing that every time my pumps shuts off it loses prime. Once it starts back up, it takes about 15 seconds to catch prime again. I recently had to replace the pump seal (3-4 weeks ago) because it was leaking. I assumed that the leaking seal was allowing air into the system. I have been in this house for about 6 weeks now and I do know for a fact that when I moved in this problem was not occurring. It seems to have started after I took apart and cleaned my filter, which was about a week after I moved in.

I have been reading about this and I keep reading about suction side and pressure side. I assume that suction side is the piping from the skimmers and main drain back to the pump and the pressure side would be from the pump to the filter and heat pump back to the return jets. Do I have that backwards?

I have figured out that if I close the skimmer and drain valves after I turn the pump off, it will hold prime. As soon as I open any of those 3 valves, air will start bubbling in within about 5-10 seconds. Does that indicate a leak in one of the pipes from the skimmers or drain?
 

h2o

Well-known member
Jun 30, 2008
68
Houston, TX
JohnT said:
I'd be inclined to bet the pump basket lid isn't sealing.
That was my first thought. I checked the o-ring real well and lubed it up with some vaseline, but it didn't help. I guess I can stop on the way home and pick up some lube and a new o-ring. That is a pretty cheap first step.

If it was the pump basket lid, wouldn't air leak in regardless of whether or not the valves were open or closed?
 

The Mermaid Queen

TFP Expert
LifeTime Supporter
Mar 28, 2007
2,522
Northern KY
h2o said:
I assume that suction side is the piping from the skimmers and main drain back to the pump and the pressure side would be from the pump to the filter and heat pump back to the return jets. Do I have that backwards?
No, you are correct!
 

h2o

Well-known member
Jun 30, 2008
68
Houston, TX
Definitely not the pump basket o-ring. I picked up a new o-ring and some magic lube on the way home and replaced it. I fired the pump on and let it prime up, then I turned it back of and after a few seconds all I got was gurgling and it lost prime.

Any other suggestions?
 

waste

TFP Expert
LifeTime Supporter
Mar 29, 2007
4,161
Coastalish 'down easter'
Somehow air is getting into the system and allowing the water to back down the suction pipes. If you don't loose water or have an obvious return leak, you can simply install a check valve before the pump (if you have enough room). If you winterize the pool and do the line blowing from the pad, you'll need one with a union.
 

h2o

Well-known member
Jun 30, 2008
68
Houston, TX
waste said:
Somehow air is getting into the system and allowing the water to back down the suction pipes. If you don't loose water or have an obvious return leak, you can simply install a check valve before the pump (if you have enough room). If you winterize the pool and do the line blowing from the pad, you'll need one with a union.
I read where you suggested that to someone else, the problem is that I litereally have about one inch of pipe between the pump basket and where it tees off to the skimmer and drain valves.
 

Ohm_Boy

TFP Expert
May 1, 2007
1,344
Orlando, FL
Which pump seal did you replace?

For me, if a system is performing a certain way, then some work is done to the system, and afterward the system performs in a different way, I generally look to the work performed for the fault.

It's not ALWAYS the culprit, but the odds are favorable.
 

h2o

Well-known member
Jun 30, 2008
68
Houston, TX
Ohm_Boy said:
Which pump seal did you replace?

For me, if a system is performing a certain way, then some work is done to the system, and afterward the system performs in a different way, I generally look to the work performed for the fault.

It's not ALWAYS the culprit, but the odds are favorable.
I replaced the mechanical seal on the motor, but it was losing prime before that. I think I can place the start of the problem starting right after I tore the filter apart and replaced some of the elements. I think I am going to pull it back apart this weekend and look over everything real well and lube that ring between the top and bottom of the cover.

Any chance that could be the cause of the problem?
 

h2o

Well-known member
Jun 30, 2008
68
Houston, TX
Okay, here is something I don't get...maybe one of you gurus can answer. If the pump holds prime when I close the valves to the skimmers and drain, wouldn't that indicate that there is a leak on the suction side somewhere (i.e. pvc from skimmers or drain)?
 

waste

TFP Expert
LifeTime Supporter
Mar 29, 2007
4,161
Coastalish 'down easter'
Something weird just happened -- I posted a reply to this ~ 20 min ago, and it's not here... :scratch: (however, if I know my computer skills - it's something I did :oops: )

Pics of the system could possibly give one of us insight as to what's going on - any chance of posting a couple?

There are so many people here with so much knowledge that I believe we WILL find out what's happening :!:
 

h2o

Well-known member
Jun 30, 2008
68
Houston, TX
waste said:
Something weird just happened -- I posted a reply to this ~ 20 min ago, and it's not here... :scratch: (however, if I know my computer skills - it's something I did :oops: )

Pics of the system could possibly give one of us insight as to what's going on - any chance of posting a couple?

There are so many people here with so much knowledge that I believe we WILL find out what's happening :!:
Computer skills I have. Pool skills? Well, that's till up for debate!

I will get some pics posted tomorrow.
 

Poolsean

TFP Expert
Apr 15, 2007
1,462
Ft Lauderdale, Florida
Did you mess with your multiport valve when you were working on your filter? Perhaps debris getting stuck in your spider gasket so it's not sealing well.

If it does not loose prime when you close your skimmer and main drain valves, it would tend to lead to a suction side leak between the skimmer and valve or main drain and valve.
You can isolate each as see which allows the pump to loose prime overnight.

When the pump is running and after it's regained prime, are you seeing bubbles in the pump basket area?

You stated
"I have figured out that if I close the skimmer and drain valves after I turn the pump off, it will hold prime. As soon as I open any of those 3 valves, air will start bubbling in within about 5-10 seconds. Does that indicate a leak in one of the pipes from the skimmers or drain?"
Sounds like (2) skimmers and (1) Main Drain, each with it's own valve? or the other way around?
Do you have ball valves or gate valves? Gate valves can leak very easily as they wear out.

I guess we'll "see" more after you post some photos.
 

h2o

Well-known member
Jun 30, 2008
68
Houston, TX
Poolsean said:
Did you mess with your multiport valve when you were working on your filter? Perhaps debris getting stuck in your spider gasket so it's not sealing well.
Yes, I backwashed and rinsed a few times to clean off as much junk as possible before I took it apart.

Poolsean said:
When the pump is running and after it's regained prime, are you seeing bubbles in the pump basket area?
Yes, but when I open up the air bleeder valve on top of the filter and bleed the air out of the filter, it tends to be a lot less.

Poolsean said:
Sounds like (2) skimmers and (1) Main Drain, each with it's own valve? or the other way around?
Yes, I have 2 skimmers and a main drain, each with it's own valve.

Poolsean said:
Do you have ball valves or gate valves? Gate valves can leak very easily as they wear out.
I honestly don't know the difference. They are like smaller versions of the multi-port valve except they only turn 90 degrees...either open or closed.
 

Poolsean

TFP Expert
Apr 15, 2007
1,462
Ft Lauderdale, Florida
You have two way valves, either Jandy valves or similar design. These may have a grease fitting knob on the side, #8 in this diagram. If they are broken off, it's sucking air. Newer Jandy valves are called neverlube valves and do away with this fitting.
http://www.poolcenter.com/parts_valves_jandy2port.htm

You're saying that it doesn't matter which valve you open, with the other two off, it still looses prime over night?
 

h2o

Well-known member
Jun 30, 2008
68
Houston, TX
Poolsean said:
You have two way valves, either Jandy valves or similar design. These may have a grease fitting knob on the side, #8 in this diagram. If they are broken off, it's sucking air. Newer Jandy valves are called neverlube valves and do away with this fitting.
http://www.poolcenter.com/parts_valves_jandy2port.htm

You're saying that it doesn't matter which valve you open, with the other two off, it still looses prime over night?
That is the valve I have. They do not have fittings on the side.

No, it doesn't matter which valve I open, it will lose prime. I just went out to confirm it again. I did notice something I hadn't before though...when I opened a valve, I would hear gurgling in the filter tank before air would bubble into the pump basket.

Here is what I think might be happening. I think I might be getting air in through the belly ring on the filter. As long as the valves are closed, the water is not able to gravitate back into the pool through the suction lines. Once I open a valve, gravity pushes the water back through that line and it sucks air in through the belly ring.

Plausible?
 

Denali

Well-known member
May 1, 2008
70
An air leak at the filter will allow the water to flow backwards through the system causing the pump to lose prime. If the equipment is elevated above the pool then it happens quite easily.

I had this problem on my pool but couldn't find any air leak. The equipment is elevated above the pool. I installed a check valve between the filter and the pump and it solved the problem. Like you I had no space to place a check valve in front of the pump.