Water pump losing prime

[brhulen]

Hello All,

We bought our 1996 Excella new in early 1997. Our 12v water pump loses its prime after a day on the road. When I looked into this, the service manager tells me it is common due to the location of the pump being above the tank. I find this a little hard to believe, but after having them replace the pump it still did the same thing, so perhaps they're right. I was thinking a simple one way valve ought to solve the problem. Currently the only way to get the water flowing is to empty the closet, and prime the pump by pouring water into the filter housing. Has anyone else had this problem and if so what have you done to fix it?

Brett

[DEITZ645]

Brett,
Both our '87 and '06 have the water pump higher than the potable water tank and we have never lost a prime that I know of. I think the pumps already have a mechanism that prevents backflow. Maybe you have a slow leak in the leg between the water tank and the pump inlet??? Small hole in tubing? Hose clamps not tight? Leak in the filter bowl? At least that is where I would start, especially if it is a new water pump.

[crestonrv]

pump has check valve to prevent that.does your pump have strainer/prefilter on it? they can cause it to loose prime by leaking air back to tank,won't show as leak unless you pressurize pick up line (normally is under vacumme).next guess is damaged diaphram in pump.

[Inland RV Center, In]

Originally Posted by brhulen

Hello All,

We bought our 1996 Excella new in early 1997. Our 12v water pump loses its prime after a day on the road. When I looked into this, the service manager tells me it is common due to the location of the pump being above the tank. I find this a little hard to believe, but after having them replace the pump it still did the same thing, so perhaps they're right. I was thinking a simple one way valve ought to solve the problem. Currently the only way to get the water flowing is to empty the closet, and prime the pump by pouring water into the filter housing. Has anyone else had this problem and if so what have you done to fix it?

Brett

The pump can lose it's prime, if the intake hose is bad, if the inline filter is bad or cracked, or if the internal pump valves are bad.

Any one or more of those problems will provide that grief.

What brand and model pump do you have?

Andy

[ZoomZoom]

The Shurflo pump will prime from 6', your closet floor may be 12" above the bottom of the tank

PUMP

Type: 3 Chamber Diaphragm
Ports: 1/2”-14 NPSM-Male.
Liquid: 130 °F [54 °C] Max
Prime: 6 feet [1.82 M]
Inlet PSI: 30 PSI [2.1 Bar] Max
Run Dry: Yes

ELECTRICAL

Motor:
Greg

[vswingfield]

I agree that you probably have some sort of leak on the intake side.

You could try printing this list and attaching it to the pump: 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97.

[DEITZ645]

Originally Posted by vswingfield

I agree that you probably have some sort of leak on the intake side.

You could try printing this list and attaching it to the pump: 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97.

ARGHHHHHH...Math humor

As jimmy Buffett says..."Math Suks"

[Lumatic]

On my 71 my fairly new Sureflo has trouble pumping just after an empty fresh water tank is refilled. It's been like this since installed. The tank needs to be full or nearly so before the pump starts actually puping water. After that no problem. Any ideas what's going on?

[brhulen]

Thanks everybody! Well when springtime comes, (it was -42 degrees yesterday morning), and as time allows I'll dive back into the closet and check for some of the solutions offered. I'm betting on the filter housing. It is a new Shureflow pump installed by the A.S. service department, so I tend to think it has nothing to do with the pump. Even the manager agreed it seems to be a common problem. I haven't seen any indication of a leak, except where I spill water trying to prime the darned thing. If nothing else maybe I'll install one of those squeeze bulbs on the suction side like they use on outboard motors to prime it. Or perhaps I could just buy another pump to prime the pump, to prime the pump, to prime the pump etc. I must say my darling wife is getting tired of having me empty the closet each time and listen to me rant.

[sander17]

Another sure sign of a leak on the intake side of the pump is air in the water. A leak on that side may not drip, but you may see "spitting" when running water into the sink. Our previous trailer had a crack in the filter housing which was impossible to see when installed deep inside the cabinet.
If you do not have any air in the water stream, I would be suspicious of the pump innards.

(Would that be a stream of air in your water stream in your airstream?)