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Water pump sucking air

I have a bit of a head scratcher with my TT.

Suddenly one day my water pump started just running on. It runs steady and only a little water spurts and sputters out of any tap. It appears to be sucking air.

It does this with a full fresh water tank. It's not the pump, the problem is on the pickup side in the tank. When I disconnect the tank pick up at the pump and put my winterizing hose on, and put the hose in a jug of water, it pressurizes and the pump stops running.

The feed pipe out of the tank goes straight down into the tank through the floor from under my bathroom sink, right close to the pump. I noticed that I can take that pipe and easily lift it up a long ways and down in the floor. That should not be happening. It seems something has broken off / come loose in the tank.

I'm not 100% sure what it looks like inside the tank for the properly functioning water pickup. I've never had the need to take one apart... until now.

I'm assuming I'll have to drop the tank and see if I can get in there to determine if something came apart.

As long as I'm on city water, all is well.

Any thoughts?
Thanks.
2007 GMC 3500 dually ext. cab 4X4 LBZ Dmax/Allison - 2007 Pacific Coachworks Tango 306RLSS
RV Rebuild Website - Site launched Aug 22, 2021 - www.rv-rebuild.com
10 REPLIES 10

opnspaces wrote:
Does the tank have a gravity fill port on the outside or is it pressure filled from the water hookup point? If it's pressure filled from the water hookup point are you sure water is making it to the tank?

If gravity fill does water come out the vent hose when full? Or does it only spit water back out around the hose?


Gravity fill port outside the TT.
I fill it until it is right full, and coming back out the fill port.
100% for sure the tank was full to the top.
2007 GMC 3500 dually ext. cab 4X4 LBZ Dmax/Allison - 2007 Pacific Coachworks Tango 306RLSS
RV Rebuild Website - Site launched Aug 22, 2021 - www.rv-rebuild.com

opnspaces
Navigator
Navigator
Does the tank have a gravity fill port on the outside or is it pressure filled from the water hookup point? If it's pressure filled from the water hookup point are you sure water is making it to the tank?

If gravity fill does water come out the vent hose when full? Or does it only spit water back out around the hose?
.
2001 Suburban 4x4. 6.0L, 4.10 3/4 ton **** 2005 Jayco Jay Flight 27BH **** 1986 Coleman Columbia Popup

Mr__C
Explorer
Explorer
How about disconnecting the inlet pipe to the pump and blowing backwards into the tank? That may clear any blockage...
2020 Keystone Cougar 26RBS "Pressure Relief 4"
2017 Silverado LTZ 6.2 4x4

MM2 USN 1970-75
USS Canisteo AO-99
USS Miller DE-1091



----------------------------------------------------------------------
"Knowledge is good". Emil Faber

Thanks for the input guys,
It was a while ago now this happened - I've been so darned busy that I have done nothing to the TT in a long time. Years. Shame on me.
I've made sure I have access to city water the past few times out.

The pipe from the tank to the pump is rigid, and although it easily lifts up out of the floor, I've not tried pulling it right out. I figure it should not be loose like that, it should be tight and sealed so water doesn't splash out the top of the tank.

Don, I do suspect something in the pickup tube in the tank. Wish I didn't have to drop the tank to get in there, but it's the only way. I have a borescope. I wonder if I could somehow sneak it in there, perhaps down the filler neck. Never thought about that until right now.

Thanks for your list John, I've never been in there, no idea if it has a strainer. I'd have to pull it apart. Valves? It was working,then stopped. Don't think any valves were turned during the time. Hole in pump inlet line? That is possible and worth checking. Pump is good, as it pressurizes with a hose in a bucket. Tank was full to the top, so that wasn't an issue. And it isn't running out the bottom.

Lantley, I could try to pull the line out of the tank and stick another in there, but I still concern myself with the apparent lack of seal there. It should be tight into the tank. I shouldn't be able to lift it up and down with ease.

I'll try to find the time to pull it apart in the storage yard to see if I can learn more about the cause.

Thanks all. ๐Ÿ™‚
2007 GMC 3500 dually ext. cab 4X4 LBZ Dmax/Allison - 2007 Pacific Coachworks Tango 306RLSS
RV Rebuild Website - Site launched Aug 22, 2021 - www.rv-rebuild.com

Lantley
Nomad
Nomad
Can you just stick a new hose from the pump into the tank and see if it works?
19'Duramax w/hips,12'Open Range,Titan Disc Brake
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wa8yxm
Explorer III
Explorer III
Suspects: Clogged outlet strainer on tank (this.. if it exists.. Is inside the tank. I found mine when I unscrewed the fitting from the outlet and that is how you remove it for cleaning)

Valve closed that should be open (Not all rigs have this valve)
Valve open that should be closed (Drain on my rig was "T"ed into the pump inlet line)

Hole in tank to pump (Pump inlet) line

Bad pump

Oh and the famous EMPTY TANK

That's the list.. Good luck List (Save for empty tank) is in Flow order.. Not suspect order)
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times

pianotuna
Nomad II
Nomad II
replace the hose between the pump and the water tank. The other possible cause is the pick up tube inside the tank.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

Thanks for the replies, but as mentioned, the problem is in the tank between the pump and the pickup in the tank.
The pump is fine as I outlined above.
2007 GMC 3500 dually ext. cab 4X4 LBZ Dmax/Allison - 2007 Pacific Coachworks Tango 306RLSS
RV Rebuild Website - Site launched Aug 22, 2021 - www.rv-rebuild.com

midnightsadie
Explorer II
Explorer II
my filter housing cracked and caused this but to prove its the tank pickup dis connect from pump install a house and gal jug see if it pumps out.

MNtundraRet
Navigator
Navigator
Have you cleaned or replaced the water filter connected to the inlet side of the water pump?
Mark & Jan "Old age & treachery win over youth & enthusiasm"
2003 Fleetwood Jamboree 29