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SueYour · 11-08-2014, 05:20 PM

2001 30' Classic that cannot draw water from the tank. New pump/no change. Separate line to pump input works. Trying to find out how to remove existing line to tank. Acts like pump is sucking air. Any advice is appreciate!

Protagonist · 11-08-2014, 05:46 PM

Not really trying to be facetious, but have you confirmed that the freshwater tank has water in it? Full to the brim? The more water in the tank, the higher the water surface, and the higher the water surface, the less air the pump has to suck in order to self-prime. It's a principle called "hydraulic head."

Bigventure · 11-08-2014, 05:47 PM

It could be sucking air. Are all the downstream fittings tight? Strainer top tight? Add a little water via the strainer to prime the pump.

SueYour · 11-08-2014, 06:02 PM

The tank is at least half full, but will fill to full tomorrow and try it out. Pump has been primed but will add water. No leaks. Thank you!

mjayjensen · 11-08-2014, 06:20 PM

Could the pump be wired so that it is running backwards?

Siegmann · 11-08-2014, 08:29 PM

Have you opened a faucet when the pump is running so it can prime itself?

idroba · 11-08-2014, 08:45 PM

The strainer on the suction side commonly leaks air if it has been moved or worked on. They crack too. Be absolutely certain that the strainer is not leaking air into the suction line.

dbj216 · 11-09-2014, 09:21 AM

It might be a kinked or clogged inlet line. I wonder if you can blow some low pressure air into the inlet line with the fresh water fill cap off. I would think you could literally blow into the inlet line like you would a tuba. I would expect pretty low resistance to air blown into the inlet line. It it makes music like a tuba, then maybe you have invented yet another amusement for Airstreamers on rainy days.

David

SueYour · 11-09-2014, 09:51 AM

Update: Filled water tank to max, turned on pump. Appeared to prime and pressurized the outlet until it turned off. Get next to zero water from any of the facets but the toilet seems to get water. Once the water level drops down about 1 gallon the pump stops pumping, runs continually. Note: all facets seem to work fine if I connect to city water. No kinks in input line. Strainer is ok, on tight. Wiring is not reversed. Still need help!

! Any suggestions?

Bigventure · 11-09-2014, 09:55 AM

The aerators are clogged. There is one on each faucet.

I missed the part where you said they work with city water.

But, they still should be pulled and cleaned.

dbj216 · 11-09-2014, 11:24 AM

So you get marginal water pressure with a full tank, but it goes to nothing after just a gallon or so is pumped out. You would expect your new pump to switch off at about 40 psi, and pump water (working pressure) at like 25 psi. The pump runs normally when you are pumping from a gallon jug of water using the RV antifreeze port and valve, right? And it will pump water to the kitchen faucet in the "test" mode. I'm sure the RV antifreeze valve is open toward the inlet line, like all the way open.

On my trailer, I think the inlet line is plumbed to a nipple on the bottom of the fresh water tank. There is an access hatch in the belly pan where the cheap, broken plastic drain valve is plumbed in. (That's why I was down there.) I keep thinking the pump can't draw water through the inlet line. You might check this connection to insure it isn't clogged.

Do check the aerators. They are known to clog resulting in very low flow out a faucet. But I think your problem is the inlet line.

At work, we would plumb in a vacuum gauge on the inlet line. I would think these pumps could pull 5" of mg without too much trouble. So if your pump is stalling but pulling strong vacuum, then you know you have a good pump on a clogged inlet line. If the vacuum goes to zero, then you know you have an open inlet line (or a bad pump).

Maybe new trailers have a "suction tube" fitted from the top of the tank. Maybe that has become disconnected and now laying in the bottom of the tank. On both of my trailers, the pump inlet is "flooded" with a connection at the bottom of the tank. But a missing suction tube could cause water pressure when completely full, but goes open once the water level drops a bit.

My old Trade Wind has a valve that allows filling of the fresh water tank with city water pressure. If this valve was open while "boondocking" with the fresh water pump, maybe the pump would draw water out of this line until it went open and then suck air. There is no provision like this on my 86. And I doubt there is one on your trailer.

David

SueYour · 11-09-2014, 11:26 AM

2nd Update:
When I connect a separate line to the output of the pump, slow very pulsating water coming out. If I connect a separate line to the input to the pump, water seems to flow good to the bathroom sink & the shower but is still a trickle to the kitchen sink. There appears to be a problem with sucking the water in on the input and also a delivery problem to the kitchen. Still Baffled in Colorado.

Bigventure · 11-09-2014, 11:34 AM

The pump will have screw on the front. The is the adjustment for the cut off switch. Turn it clockwise to increase the pressure cut off.

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SueYour · 11-09-2014, 11:41 AM

3rd Update,

The aerator for the kitchen was plugged up, cleaned and now it works ok with an external input to the pump. Still a problem getting the water from the tank to the pump. Only 4 connections and they all seem fine. Is there something in the tank with this year and model that could cause this?

Bigventure · 11-09-2014, 01:40 PM

You could always open the fresh water tank fill and drain then blow air into the suction line.

You have to flush the lines without the aerators on to clean it correctly. Or it will only clog again.

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dbj216 · 11-09-2014, 06:18 PM

Glad you found the plugged aerator. It was a good suggestion. One less problem to worry about.

Your testing confirms there is an open inlet line somewhere. The pump is sucking air or sucking a plugged line. It works okay drawing from a alternate reservoir. If you put your thumb over the temporary inlet hose, you should feel the vacuum. If you plug the temporary inlet, the pump will work hard drawing max vacuum. If you leave the temporary inlet open, the pump will just sit and run on idle. See if the pump noise you here when doing these two experiments is similar to the noise you hear with the pump hooked to the fresh water inlet line. Plugged or open line.

I think you're pretty confident you could put a five gallon bucket under your trailer, hook your pump inlet to it, and you would pump nice flow to all of your faucets. We gotta figure out what's wrong with the pump inlet line.

I'm no help here as I don't know how the tank is made.

David

idroba · 11-09-2014, 07:30 PM

The strangest one that I ever ran into was on a 71 Caravel which would not pick up water with a new pump. I could see bubbles in the intake strainer so air had to be coming in somewhere. I finally determined that the hose itself was leaking air in under suction, but no water would leak out given the small amount of pressure on it from the bottom to the top of the tank. When I replaced the intake hose (which was not easy to do) the problem went away. So, the original hose looked good but was rotten and let air in.

Castaway · 11-09-2014, 07:43 PM

Did you by chance install a winterizer bypass kit? My pump stop working after I did that on our 22' sport, turns out that the length between pump and FW tank could be no longer than 6 feet and that extra 6 inches from adding the kit was making it to long. When I removed the kit the pump worked fine.

Gary