freshwater pump losing prime

5

5knuckle

Member
Joined
Apr 22, 2008
RO Number
29927
Messages
16
I have a jabsco 12V diaphram freshwater pump that refuses to remain primed for more than a few minutes. The pump is mounted higher than the tank and if I open the water heater valve (below the pump) it will pump and and stay primed for a short time. if I open the faucet it will not prime and seems to spit air. I cannot find any air lead between the tank and the pump inlet. I am assuming this is bad diaphram - is this the correct diagnosis??
 
check the filter screen at the tank outlet, if any
 
There is usually a check valve of some sort near the tank and/or the input to the pump. These occasionally go bad which will cause your problem.
 
Are you sure the water tank vent line is not clogged?
Just a thought.
Bill
 
Thanks Bill,

Jabsco 31595-0092 is the model number. I do not think that the vent line is plugged or it would not pump "downhill" when I open the water heater valve. It is filling the water heater with pressure fine but it won't pump uphill...
 
Open the pump there might be something stuck in one of the valves.
 
I'll second George's suggestion - look for a check valve that is leaking back into the tank. If that isn't the problem, I'd look at rebuilding or replacing the pump.
 
I have had the same issue caused by a check valve at the hot water heater as caltexfla said.
 
Thanks for all the suggestions. Replaced the pump last night and everyhing is working great now.
 
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