Water Pump Flow - SOLVED

JCALD

We have a 2019 Tab 400 and I need to know if our water pump is defective.  When you first turn the faucet on after the pump has reached pressure the flow is good for about 5 seconds.  After that the flow reduces to just a small stream (about 1/4” diameter) that is totally inadequate to run the shower.  Water literally dribbles out of the shower head once the initial pressure is lost making the shower function while boon-docking totally ineffective.

Here are a couple of pics of what I see in our sink.  Just need to know if this is normal like my service dealer says it is.

If it is in fact normal, then is there a recommended replacement pump that will actually move some water?

Sharon_is_SAM

Our flow from the “hot” water faucet is much better when the Alde is turned on and heated.

Dutch061

Not normal, we have a 2020 400 BDL and the water flow is the same from initial faucet opening until the tank is empty.

rh5555

I agree with @Dutch061, not normal.  Our 2020 400 BDL also behaves like his.  It might not be the pump, though:  If the pipe from the freshwater tank to the pump is obstructed, you will observe the same effect.  These pumps do not work well with a restricted feed.

pthomas745

Have you looked at the pump filter?

Dutch061

pthomas745 said:

Have you looked at the pump filter?

pthmas makes a great point, if it is sucking air (cracked filter housing) or if the cover gasket is rolled or similar it can draw air. What you would likely notice is a very rapid running fresh water pump due to the air leak. And you may or may not have extra bubbles in the outlet. Common sense tells me that you would always have trapped or extra air in the pressure side but not necessarily.

There was another thread a while back where the owner was having issues "priming the pump" so to speak and the filter housing was cracked. Not sure where the pump is located on 2019 but in my 2020 with the small 2 way fridge there is an access cover (lifts off) in the wardrobe closet.

Brad

Denny16

Yes, the water pump is under the closet floor, along with the water lines and some valves.
cheers

JCALD

This issue has been present since we picked the trailer up in October of last year.  I had previously checked the filter but did not look for a crack in the housing.  I will do that today and make sure all is well.  I really suspect there is some kind of restriction (plastic crap in the line) from when they drilled holes in the tank to install the pickup line.  I have had previous problems with the tank draining due to this and a little air blown through the pipe cured that problem.  I will try the same with the siphon line to make sure it is clear.

We had the unit in to a local NuCamp dealer for warranty service on a few minor things of which one was the poor pump performance.  Very disappointing that the tech said it was normal and we have been dealing with it since.  If I can't resolve it then we will reach out to NuCamp.  I have had great experience with their warranty group.

TNOutback

Definitely not normal.  I was pleasantly surprised at the water pressure when we got ours last year. As previously mentioned, you could have a clogged filter or a cracked housing at the pump.

At least in our 2020, the pickup and tank drain use the same port in the fresh water tank.  If you are getting good drainage from the tank, then I wouldn’t think it would be anything inside the water tank blocking the water.

JCALD

Checked out the water filter and housing and all is well with them.  Cranked up the compressor and blew out the siphon line and what do you know, the water runs like it should.  I suppose there was some plastic bits clogging the line or it was up against the tank and restricting flow.  The pump sounds completely different now and manages pressure in 1/10th the time it used to take.  Anyway, it works great now with no help from the tech minds at the dealer.  Thanks for everyone’s input.

Also, I am intrigued by TNOutback’s comment on the source for the siphon hose.  Is there a schematic on the forum of the 2019 era 400 plumbing?  Having a common source for both the drain and siphon makes sense.

TNOutback

@JCALD I discovered the common connection when I dropped the corner of the underbody to insulate the fresh water tank drain fitting.  That’s when I was able to see that the pickup line from the water pump taps into the tank drain line.  I would think you could drop enough of the underbody cover to access the fitting into the tank - if you have the problem again.  If there are indeed shavings inside the tank, there’s a good chance water flow will bring them back to the drain port again.  At least on mine, it is right behind the wheel and not the easiest place to get at.

Some day I am going to drop more of the bottom to get at the drain and siphon lines to completely wrap them up with some pipe insulation.

ScottG

Here's a photo from my 2015 S, if you are interested. The underbelly cover wasn't added until later model years.

TNOutback

Same connection, except tank penetration is on the side.

JCALD

Thanks guys, that is good information.  If the problem becomes chronic I will take it back to the dealer while it is still under warranty and tell them what they need to do.  

Sharon_is_SAM

The side tank penetration is why they now advertise usable tank volumes instead of actual holding capacity.

Dutch061

JCALD said:

Thanks guys, that is good information.  If the problem becomes chronic I will take it back to the dealer while it is still under warranty and tell them what they need to do.  

Tell them for a fee that you will provide training for their "experts" that obviously know very little. Being an ASE Master Technician - Engineer is not always my friend. I trust very few people to touch any of my stuff because there are so many ignorant people or people who just don't seem to care because it "isn't theirs".

Brad

jameskuzman

Sounds like you've solved the problem, @JCALD, and I'm late to the game here, but my suggestion was going to be to disconnect the inlet side of the pump and stick it in a gallon jug (like you would when you winterize) or even a larger bucket if you can squeeze it in and see if the problem continues or goes away. 

If it goes away, the issue is upstream (toward the tank); if it persists, it's something downstream of the pump (toward sink/shower taps).

Jim

JCALD

Update and Problem Solved:  A few days after blowing the suction line out and having the pump work like it should, the pump went back to it’s old ways.  I pulled the tank cover from under the trailer and found the fresh water tank outlet.  It is located on the drivers side end of the tank, just above the drain valve and about half way to the axle.  The drain line and suction line feed off of the same tank outlet (as mentioned by others in this post).  With a little dremel cutoff wheel action on the PEX clamps the line was easily removed.  The connection to the tank is molded into the tank and takes a 3/4” x 1/4” PEX male fitting, so it was easy to remove and replace.  Once removed I found the problem.  There was a piece of plastic and what appears to be some hot glue residue just before the first elbow in the line (pic below).  Flushed the tank out with fresh water to make sure there was nothing else waiting to enter the line.  Got everything back together and all is well again.  This should permanently fix the problem.

My biggest problem in this “warranty” repair was having to buy a PEX Clamp tool and associated elbows, fittings and pipe.  Although this is much better than taking it to the dealer and waiting 3 weeks to possibly get it fixed.

Thanks to everyone for providing good information.  Hopefully this is a rare occurrence for most of us.

Bayliss

@JCALD, thank you for posting the resolution and photos.  It is always helpful to learn how these issues are fixed.

NomadPilgrim

Hmm maybe I'm hating on my water pump, and it's not at fault. 

TNOutback

Thanks for the photos and procedure.  I want to drop the bottom and insulate the pickup and drain lines, but haven’t got the inspiration just yet.  

BrianZ

Great work, @JCALD, and thanks for sharing the photos & description of the fix. 

I wonder if they try to flush debris from the tank at the factory before adding the rest of the plumbing.  It seems like there have been enough reports of this kind of issue affecting the pump or drain that they would have put some kind of preventive measures in place.  If moving the output tap from the tank bottom to the side was supposed to be the fix to avoid debris plugging the lines, then it not only failed, but created new issues in the process (poor drainage & reduction of usable tank volume).

trimtab

Send pictures to nuCamp.

JCALD

Pictures sent.