Bubbles, Filter Drains Down - normal?

ekim

Member
May 4, 2013
17
nj
When my pump shuts off I get lots of bubbles in the system. It seems as if the filter is draining out into the pool.

If I leave the pump running non-stop for a few days, I have zero bubbles in the pump housing.

There are no check valves in the system that I can see.

Should the filter hold water, or at least most of it's water when the pump is shut off?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
30,000
Laughlin, NV
The filter and pump should remain full. You have a leak somewhere. Might be on the pressure side. Any water showing up? If not, when you turn off the pump, listen for air being pulled in. Leaks can seal under pressure with water but then suck in air when under vacuum.
 
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ekim

Member
May 4, 2013
17
nj
The filter and pump should remain full. You have a leak somewhere. Might be on the pressure side. Any water showing up? If not, when you turn off the pump, listen for air being pulled in. Leaks can seal under pressure with water but then suck in air when under vacuum.
I could hear the air being pulled in. Found a wet plug on the filter valve (I guess a plug for a pressure gauge?) and a water "bubble" on the PVC pipe coming out of the pump. Addressing these seems to have fixed the problem.

Thank you for the quick reply and excellent debugging suggestions.
 

ekim

Member
May 4, 2013
17
nj
I think there are two possible places to put a gauge. On the valve, and on the top. The valve appears to be a small NPT fitting. The top seems to be something sealed with an O-ring. Is one preferred over another?

FilterTop.jpg
Valve.jpg
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
30,000
Laughlin, NV
Pressure gauges typically come with a 1/4" NPT male fitting. It also needs to be measuring the pressure before the filter media.