RV 12v water pump runs in 1 second bursts only on hot side

timotb

Member
Troubleshooting an RV 12 volt electric water pump that runs in one second bursts on the HOT side (not allowing the Girard tankless hot water heater to fully activate). Pump runs constant and correctly on the COLD side. When connected to city water via a hose, both hot and cold run correctly. Problem only recently started. Tankless water heater working fine for two years.

This is a on Winnebago 2010 ERA 170X but don't feel the issue is related to make and model.

Suggestions/comments?
 
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It sounds like there is a restriction on the hot water side only allowing a little water through. Do you have a water heater bypass valve that might be stuck in the middle between open and bypass?
 

timotb

Member
It sounds like there is a restriction on the hot water side only allowing a little water through. Do you have a water heater bypass valve that might be stuck in the middle between open and bypass?

That's what I was thinking too. I will check for a bypass tomorrow. But why does it work fine in city water mode? Pump getting weak?
 

timotb

Member
Problem solved.....(drum roll).....It was the adjustable flow restrictor valve on the in-side. Manual said it was set by the factory to be full open. When I tried to move the valve, it was stuck and needed slight help from a plyers. Bottom line is was only 3/4 open. Fixed

Thanks to all who commented here.
 

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