Fresh water pump problem.

[Dan50]

I have an Elkridge 34QSRL and am having a problem with the water pump. The pump comes on when any faucet is opened or the toilet flushed. There seems to be a lot of air in the line at times so you would think that it is sucking air on the intake line or a leak on the output. Water pressure is not that great either. The thing is that the pump will shut off when the faucet is shut off and hold pressure. It does not cycle quickly like it is losing pressure when shut off and has to build it back up again. Sometimes it will not shut off unless you open up both faucets to get a strong flow then shut them of. The pump will then build pressure and shut off and hold pressure. I'm thinking that if I have a leak anywhere then the pump would not shut off and hold pressure. Suggestions or ideas?

[Jetstreamer]

I had the same problem once and it was a hairline crack in the pump strainer/filter probably caused by a poor winterization job from previous owner. Cracks were barely visible but were the cause of the air leak.

[Itching2go]

C Schomer wrote:
3' up is a long way. That's equivalent to -1.3 psi. The way I figured out I had a suction leak was... after I put an inline strainer (with a clear bowl) on the pump, I would see bubbles that never completely cleared up. Maybe you can put something clear, ahead of your pump so you can see for sure if it's an air leak. Craig

Actually, the line into the water pump from the freshwater tank was clear enough that I could see the steady march of bubbles. That's what tipped me off that I had an air leak on the supply side in the first place. Put the new strainer on yesterday, and no more air in the line. So all is good. As for the 2 or 3 foot rise, I also turned the flow/pressure adjustment on the water pump up a quarter turn when I had it out on the bench, which improved the flow a bit. Only downside of that is that it seems that the pump runs a bit louder than before, which is certainly livable. All is well, and we're ready to head out to Cape Cod and Vermont this coming weekend.

[C_Schomer]

3' up is a long way. That's equivalent to -1.3 psi. The way I figured out I had a suction leak was... after I put an inline strainer (with a clear bowl) on the pump, I would see bubbles that never completely cleared up. Maybe you can put something clear, ahead of your pump so you can see for sure if it's an air leak. Craig

[Itching2go]

C Schomer wrote:
Does your pump have to suck the water up hill very far? My current 5er has the tank in the belly and the pump is in the basement so it's about a foot higher than the tank bottom. I made some changes and had a tiny suction leak and it acted like yours. I clamped a 3/8 hose onto a barbed fitting and the clamp was a little too big and it didn't squeeze down evenly and left a slight leak. It looked fine but it wasn't. Craig

My water pump is in the basement, about 3 feet or so above the fresh water tank. The tank itself is at the rear end of the trailer as well, which makes the length of the line between pump and tank somewhere in the area of 20 feet or so. So, to your question... laterally about 20 feet and uphill 3 feet or so.

[C_Schomer]

Does your pump have to suck the water up hill very far? My current 5er has the tank in the belly and the pump is in the basement so it's about a foot higher than the tank bottom. I made some changes and had a tiny suction leak and it acted like yours. I clamped a 3/8 hose onto a barbed fitting and the clamp was a little too big and it didn't squeeze down evenly and left a slight leak. It looked fine but it wasn't. Craig

[Itching2go]

Dan50 wrote:
Thank you everyone. I'll check for a leak on the suction side. All valves are as they should be.(pump, hot water and winterizing valves.

Good advice, here. I just experienced the exact same problem... whenever opening a faucet, the pump would run, pressure would drop, water volume would be very low with a lot of air purging out of the faucet. After the air was purged, pressure and water flow would increase to the point that it was usable, but it would take as much as 5 or 10 minutes before we'd get to this point. After use, when the faucet(s) were shut, the pump would pressurize the lines and shut off just as it should.

My initial thought was that I had a bad pump, so pulled it out and opened it up on the bench. All looked good... diaphragm in good shape, seals all looked good... so I put it back in and watched the water flow through the incoming water line on the suction side. Noticed that whenever the pump was running, there was a steady march of air bubbles coming up the intake line from the fresh water tank. Hmmm.... Air leak seemed to be the culprit. Traced the line back towards the tank and ran into the SurFlo water strainer. It looked good... no cracks visible... but took it out of the line anyway. Sure enough, no air in the lines on the suction side, and all is well. Thinking that it either has a hairline crack somewhere or more likely, the O ring started to leak under pressure.

Received a replacement strainer from Amazon just yesterday ($6 or $7 bucks) and will be putting it in this weekend. One of those "20 hours to diagnose and 10 minutes to repair" situations.

Hope this helps.

[Dan50]

Thank you everyone. I'll check for a leak on the suction side. All valves are as they should be.(pump, hot water and winterizing valves.

[Paul_Clancy]

Check the Rv winterizing valve

[avvidclif1]

Dan50 wrote:

RAS43 wrote:
Because even with air in the pressure side the pump can build up to the shutoff pressure and shut off. It sure sounds like you have a leak on the suction side of the system.

I can't see how this is possible. If it has a leak on the suction side how can it build pressure and shut off and not keep running or cycle every so often? Maybe I am just a little thick today.

The outlet side of the pump is pressurized and where the pressure switch is. The inlet side is not pressurized and if air is leaking in thru a bad connection then when first turned on the air will show up and then clear up (maybe) but when the faucet is closed the pressure builds up and the pump shuts off... And as long as there is not a leak on the pressurized side it will stay off.

[Old-Biscuit]

Because the pump has an internal check valve so discharge line pressure (which is what pressure switch uses) doesn't leak down back thru pump

You have a small air leak suction side of pump.......not big one or pump would have problem priming. Loose fitting/loose strainer/small hole in suction line/crack in pump t suction strainer etc.

[lakeside013104]

Check the tightness of your inlet and outlet connections to the pump. Check to see if the strainer on your pump is clogged or loose. Keep us posted.

Lakeside

[greende]

Because the leak is only partial and it does draw enough water to pressurize the system. I agree that this sounds like a problem on the suction side.

[Dan50]

RAS43 wrote:
Because even with air in the pressure side the pump can build up to the shutoff pressure and shut off. It sure sounds like you have a leak on the suction side of the system.

I can't see how this is possible. If it has a leak on the suction side how can it build pressure and shut off and not keep running or cycle every so often? Maybe I am just a little thick today.

[RAS43]

Because even with air in the pressure side the pump can build up to the shutoff pressure and shut off. It sure sounds like you have a leak on the suction side of the system.