Ask Your Question

Angie's List Answers is the trusted spot to ask home improvement and health questions and get answers from service companies, health providers and consumers. For ratings and reviews on companies in your area, search Angie's List.

Top 30 Days Experts
Rank Leader Points*
1 kstreett 240
2 Guest_9020487 110
3 Guest_9190926 105
4 GoldenKid 100
5 ahowell 95
6 KnowledgeBase 95
7 skbloom 80
8 Guest_98024861 70
9 Guest_9311297 70
10 Guest_9400529 70

*Updates every 4 hours

Browse Projects By Category

Question DetailsAsked on 3/27/2013

My pool pump primes but will not hold suction and the water flow quickly drops from 10 to 20 psi to 2 or 3 psi. I have an air leak somewher

The pool pump is a 1 and 1/2 HP PentAir which was installed new in Ocotober 2011, but stopped pumping properly in May 2012. I spent last summer trying to locate the cause of the loss of prime and have checked all of the PVC piping for air leaks and have checked the Hayward filter which doesn' t leak under the pump's pressure. I have replaced all of the brass gate valves and had a knowledgeable neighbor who is a professional Handyman take the pump apart and put it back together, but with no success. I can't find where the leak is which causes the pump pressure to drop.

Do you have the same question? Follow this Question

2 Answers


The leak may not be at the pump but rather elsewhere in the line. If it is sucking air you'll have to find out from where. Can you isolate parts of the system to do a vacuum test? You can also back pressure the line with some food coloring in the water to look for a leak. I'm not a pool expert but have needed to work on pumps on ranches before. A leaky line that's 100+ yards long takes some time and patience for sure. Try the back pressure test with dye first as it'll be the easiest. If the leak in the system is above ground you'll see it pretty quickly. If you still have trouble it's probably time to call in a pool service professional.

Answered 7 years ago by Todd's Home Services


I am going to asssume your pump also provides the circulation for the pool cleaning equipment. I also have to make some assumptions about your pool's plumbing, which might or might not be right. Also, when testing do not run the pump for more than a few seconds at a time, because you do not know how much water it is getting - the 2-3 psi might be just air pressure against the filter tank static head. I would open a drain valve somewhere downstream of the pump and make sure it is pumping at least a slight flow of water before running it more than about 5 seconds at a time for testing. It would be helpful if while you do the checking, you had a family member turning the pump on and off so it runs as little as possible.

1) First, check that the isolation valve(s) on the incoming line to the pump has not been closed.

2) Second, check the skimmer basket right before the pump (and the ones along the pool edge that skim gutter trash) are clean, as well as the pipe inlet the strainer basket guards.

3) Third, check that the water level in the pool is high enough so there is water running into the collection trough all the time. Unless you have separate intakes or your primary water intake is at the deep end drain (which some modern pools no longer use as the primary return because of the suction drowning cases in recent years), the system needs water to run, and some pull primarily or solely from the gutter. Also check the gutter screen for clogging.

4) Check the filter and pre-filter screen, if any exist on the suction side, for clogging - if they are mostly clogged enough water would fill the pipe to prime, but once it started sucking it would stall, not pumping any significant water through the pump. Those on the outlet or pressure side are irrelevant here because they are not getting pressure.

5) Ditto for the debris baskets - if they are plugged, leakage while they sit would allow priming but not enough water flow to pump any significant amount of water. Note this is not the same as a pressure failure - it would still show almost no output pressure because there would be no water flowing INTO the pump, hence almost none out. While checking those, also check obviously for an air leak INTO the line at that point - the intakes below the baskets and screens should be submerged.

6) If you have multiple intake shutoff valves, close them one at a time and see if the pump starts working right - if so, that line is the one with the problem, somewhere from there back to the pool.

7) Next, IF shutting off the pool cleaning vacuum line valve solved the problem, dump all the suction line flex hose in the water and hold it under the water and see if that solves the problem - if it does, work along to find where the crack or hole is. If not, check if a pool sweep or suction hose connection point is open and above water level - some are installed in the pool edge where they will suck air if they leak, some just under the water line. Also,, if you have a skimmer or pool bot or whatever connected, throw it in the water - its float valve may be letting air in.

8) People are going to start thinking I am a pipe surgeon at heart if I keep suggesting the same solution all the time for leak detection, but it works. If all the above fails to find a problem, get a $10-15 metal stethoscope at a box store or pharmacy, and starting at the pump work backwards down the suction line listening for a whistle or bubbling or sucking sound. Should be pretty easy to find. To listen to the pipe under the pool deck takes a bit of on-the-knees work. If the line passes under grass, drive a metal rod a few inches into the ground and hold it in place LIGHTLY with a single finger on the top (to avoid absorbing vibrations) and hold the stethoscope against the side of the rod, moving along the line in 3 or 4 foot increments.

A quick pump check last, though I really do not think that is the problem:

9) you should have a washdown or drain faucet somewhere downstream (pressure or output side) of the pump - open that, then pour a 5 gallon pail of water or a hose (being csrefgul not to get electrical wet) into the debris basket or strainer hole right before the pump (after cleaning the basket out) - the pump will suck that water right out and pump it out the faucet in a good stream if working right, until the intake water is gone.

10) You can also shut off the isolation valve downstream of the pump or filter (but upstream of the gage) and do the same thing - it should build full pressure and hold it if the pump is working right.

11) If during this test it starts off OK then drops off pressure immediately as it has been, listen for air sucking into the pump housing somewhere. Another test is the same 5 gallons or hose into the basket hole, but hook a hose to the pump outlet at the first drain valve, and put that into a bucket of water. When you turn the pump on, if it is sucking air between the basket and the pump (including at the pump) a lot of bubbles will come out of the hose in the bucket - if not sucking air, then no significant bubbles. If bubbling, could be a cracked pipe, a shot pump gasket, or a leak around the power shaft, though that would have to be pretty bad to drop pressure to near zero.

By that time you should have found the leak - then decide if a pool man or a plumber is the right person to fix it, if you can't do it yourself.

Answered 7 years ago by LCD

Related Questions

Terms Of Use
Privacy Policy