Very low hot water pressure, pump issue

[TrailDude]

2019 FC 19CB
Went to flus out for the first time, put water in the holding tank. Cold worked/flused fine. Hot had very little water pressure and the pump was freaking out when on hot. Hot water heater was on bypass. I would not think this was the problem so to eliminate I took off bypass and let the hot water tank fill. I hooked up to the city water connection to see if that made a difference. Decent cold pressure but still very little hot water pressure. Unhooked the city connection and turned the pump back on, same thing, decent cold and lousy hot pressure and the pump freaks out on hot. I have attached a sound file, you will be able to tell when I turn the kitchen sink from cold to hot as the pump freaks out. Any ideas what this could be??? Thank You from a newbie and not too mechanically inclined

OK, can seem to get my audio file in a format that will work... when on hot the pump quickly pulsates!

[A W Warn]

My guess: Either the mixing valve on the water heater or the aerators on the faucets have accumulated debris in the screens.
I'm guessing the pulsating is from low water flow, causing the pump to turn on and off quickly.

[KelloggKid]

Given that you seem to have adequate water pressure on the cold side of things I would say there is nothing wrong with your aerators. Do a search of this site for "mixing valves" and you will find that there is a rash of folks every spring with the exact same symptoms your are experiencing. When the water system is first fired up after sitting all winter, debris from the water tank plugs up the mixing valve.

You may find some posts where folks have chosen to replace the valve but that isn't exactly inexpensive nor easy to do depending on the model of trailer. Before doing that I'd recommend finding a way to get the water heater full of vinegar, turn it on and heat it up for a couple of hours, and then pull the drain plug out and use a flushing wand and a hose to get the debris out of the water heater.

We had the exact same thing happen last spring, which was the first time we de-winterized our AS. After flushing the water tank out we used it as is and I don't know if we were just lucky or if it was the heat from the water tank but it was only a couple of days and the flow returned to normal.

Best of luck.

[HowieE]

I am going to assume you have pressure, momentarily, from the hot water side when you first turn it on and the pump was at pressure.

If that is the case and the flow rate drops off and the pump starts to shot cycle while you continue to draw hot water that clearly indicates a clog. First place to look is the mixing valve.


If you can't get to it for cleaning I would remove it altogether as I will be a problem for ever. It is another system designed to protect us from ourselves. If you have a brain you don't need it.

[Al and Missy]

I looked at the plumbing diagram for one of the newer trailers for another problem. On that one, at least, the "bypass valve" is not a bypass valve, it shuts off flow to the water heater. That may be your problem.

Al

[TrailDude]

Outside of the dealership testing the system this is the first time water has been put in the AS. Is it really likely that there could be a corrosion clog at this stage in the AS life cycle? With very little access to the unit and no plumbing experience it sounds like my best bet is to head to a dealer for a warranty check out. I know it is not the aerator at the faucet because the low pressure/pump freaking out on hot is at both sinks and both shower spigots. I am afraid to keep using it also for fear of damage to the pump as it sounds really bad when accessing hot water.

First trip is slatted for this Friday about two hours north. If I take the longer route there is a dealer a little over half way there. Now, if they will work me in and not blow up the weekend will be the next question.

[A W Warn]

Originally Posted by TrailDude

Outside of the dealership testing the system this is the first time water has been put in the AS. Is it really likely that there could be a corrosion clog at this stage in the AS life cycle? <<snip>>

Maybe, depending on the minerals in the water that was inside the trailer's plumbing system. Acidity of the water affects this too. Minerals in the water precipitate out and/or combine with the aluminum of the hot water tank. This creates a fine white/cream/yellow colored scale that can clog up plumbing.

There are some specific cleaning/flushing instructions in the water heater manual.

I would remove the water heater drain plug then turn on the water, to get some back flow going through the WH.

[uncle_bob]

Hi

Since this is a brand new trailer on it's first pass out of winter storage - I'd cycle all the valves a second time and double check that each is in the correct position after cycling.

Bob

[Bob Peahl]

Originally Posted by TrailDude

2019 FC 19CB

Went to flus out for the first time, put water in the holding tank. Cold worked/flused fine. Hot had very little water pressure and the pump was freaking out when on hot. Hot water heater was on bypass. I would not think this was the problem so to eliminate I took off bypass and let the hot water tank fill. I hooked up to the city water connection to see if that made a difference. Decent cold pressure but still very little hot water pressure. Unhooked the city connection and turned the pump back on, same thing, decent cold and lousy hot pressure and the pump freaks out on hot. I have attached a sound file, you will be able to tell when I turn the kitchen sink from cold to hot as the pump freaks out. Any ideas what this could be??? Thank You from a newbie and not too mechanically inclined



OK, can seem to get my audio file in a format that will work... when on hot the pump quickly pulsates!

Have you tried opening the water heater pressure relief valve? The heater tank can develop an airlock, which is resolved by opening the relief valve (pump off, city water off). It is necessary to have some air in the tank. I leave the valve open until it stops draining water.