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Wednesday, September 25, 2013

Fresh Water Air Lock

I have a ShurFlo 4.0 Smart Sensor water pump in my coach and I get an airlock in the line. I have had the fittings tightened and it still has to burp the air out to run right. It reoccurs in minutes when not in use. With the pump switch on or off it does not make a difference. If I leave the pump switch “on,” the pump will start running without turning on a faucet. It will run until a faucet is turned on and the air bled off. The pump will be hot if I do not turn the water on. I have no water being pumped out when this happens. Do you think that the water could siphon back into the tank allowing the air to get in line? My service provider has not been able to cure this. Don W., (Decatur, AR)

Don, it is quite possible your Smart Sensor is indeed allowing air into the system. It’s probably more evident when you switch from city water to the on-board source via the water pump. Contrary to others in their model line, the ShurFlo Smart Sensor was manufactured without a backflow preventer in the discharge fitting. I would suggest you install an aftermarket check valve (backflow preventer) directly to the outlet side of the pump and see if that doesn’t help. Perhaps the addition of an accumulator will help as well. I recently tested their model 4008 pump and it performed wonderfully. It’s very quiet and is self-priming. If all else fails, perhaps an upgrade to the 4008 is in order. Also, the 4008 pump nullifies the requirement for an accumulator; another plus for upgrading.


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