Water pump does not prime

[ipso_facto]

I turn on the water pump, it runs, but nothing comes out of the faucets.

I first thought my water pump was bad. I eliminated that possibility by disconnecting the hose to it and sticking it in a dish full of water - it pumps it well.

Then I though the filter was bad, and so I disconnected the hose leading to it and stuck it in some water, and it still pumps.

But when I connect everything together, the water pump does not pump water from the fresh water tank. It cuts on, runs and nothing happens. The water does not even get to the filter, not a drop.

Has anyone experienced exactly that situation?
Something is wrong with the hose from the fresh water tank leading to the water pump.
Is that hose cracked, plugged up or has an air leak somewhere? How exactly do I access it on that model?

[sovereign]

i have the same problem, can anybody help us?

[dinoburb]

Hi,

Well, I had the same problem and worse. The following thread should be of some help:

http://www.airforums.com/forum...ead.php?t=5242

Vacuum is the cluprit, lack of it that is. Check your strainer and the plumbing leading up to the pump.

Take care,

[ipso_facto]

What is this strainer, and where is it located, and how do I access it, etc.?


P.S. Just to be clear, my city water works just fine. I am only having problems with pumping from fresh water tank.

[dinoburb]

Hi,

You should see a small canister looking device just 'in front' of the pump. By 'in front' I mean just before the inlet of the pump. The strainer is designed to trap debris and other fairly large contaminates before they can damage your pump. So . . . somewhere between the inlet of the pump and the outlet of the fresh water tank you should find a device with two ports connected to the tank and the pump. If the strainer assembly has even a hairline crack you will be unable to create a vacuum and draw up the fresh water. I have replaced mine with a different brand and size, but originality is not my goal. Simplicity and ruggedness is!! I'd love to send you a picture of mine but my trailer is in a storage lot not co-located with my home.

Take care,

[ipso_facto]

That's something different from the filter?

I disconnected the line going into the filter, and tested the water pump, it works just fine pumping from a cup full of water, so this tells me that the water pump, the filter, etc. are all working and not sucking in any air. It just won't pump from the tank.

So the problem seems to be with the fresh water tank, or with plumbing near the fresh water tank. I traced the plumbing under the closet and saw the hose turn into a polybutylene (dark gray line) going straight down where the fresh water tank is, but I couldn't trace it any further than that.

[BobbyW]

When you disconnect it from the pump, can you blow air backwards toward the tank?

[ipso_facto]

I will try to and get back to you.

[dinoburb]

Hi,

Can you bypass the filter/strainer and connect directly to the pipe coming from the f/w tank? If you can you can see if the filter/strainer has a vacuum leak or that there is another problem closer to the f/w tank.


Take care,

[ipso_facto]

dinoburb,

I connected the pipe directly to the tank bypassing the filter and it still wouldn't pump anything.

I can pump from a cup full of water and I can pump with the filter attached, which eliminates both as causes of the problem. It's something else.

[nickcrowhurst]

Ipso, BobbyW's question is crucial. Last month I helped a friend who had just this problem on a 79 Sovereign 25ft rear bath. The pump would draw water through the filter from a cup, but not from the tank. We first made sure the tank was full! I disconnected the tank-to-filter pipe at the filter, and blew down it. The air did not bubble through water, and we could hear air escaping. We then sucked on the pipe, and only air came up. Further investigation revealed that we needed to tighten the hose clamp which secures this pipe to the tank spigot. This cured the problem. Access to this clamp was fairly easy on the Sovereign, but I don't know about your model. Someone else may be able to advise, but on my Excella, I might have to lower the steel belly pan. Good luck. Nick.

[ipso_facto]

When you disconnect it from the pump, can you blow air backwards toward the tank?


I tried that. I can -- I heard the type of sound you get when you blow air through a straw in a glass of water, and what seemed like some water in there. What does that mean?

Precisely at what point is it not getting pressurized?

I only have about 4 gallons of water in the tank, I will try adding more and see if that changes anything. I did however try to pump with a full tank last fall and got the same result.

[nickcrowhurst]

Ipso, the bubbling sound means you have water in the tank, sufficient to cover the outlet. Now you need to suck on the end of the pipe. If you can suck water up into your mouth (several deep breaths, clamping the pipe off or blocking with your tongue between sucks), then the pump is not pumping hard enough to overcome the head of water. You then ned to overhaul the pump using an overhaul kit from the manufacturer. If you can't suck the water up, then you have an air leak. This could be a split pipe, a loose hose clamp at the tank outlet, or a cracked outlet spigot at the tank. The latter two might reveal themselves by a drip of water from the belly pan, but if they were slight leaks, water might not escape. If the tube, spigot or clamp are the problem, as stated in my previous post, you might have to lower the steel belly pan. Before doing any of the above, I would fill the tank to make the sucking easier, and to ensure the outlet is well submerged. The fact that the pump would empty a cup of water does not eliminate it as a possible cause. You need to test it against a head of water, as when it is trying to raise the water a foot or more from the tank. Good luck. Nick.