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Grandpavan · 06-24-2017, 09:14 AM

I'm sure this isn't just a Thor issue but thought I would start here. Out 2017 Challenger 37KT has had a pulsing water pump since day one. It is going back to the dealer the first of next month for a variety of issues, but thought I would send out a question to the Thor family. It may be an easy quick fix which I don't mind doing. Any suggestions as to the cause of the pulsing water? I thought maybe a vacuum somewhere but all water outlets function properly.

BFlinn181 · 06-24-2017, 10:09 AM

Pulsing water can be smoothed out by an accumulator tank. This tank, with a rubber bladder and an air pocket, absorbs pulses and sudden water flow stops.

Accumulator Tanks

soonerdave · 06-25-2017, 06:09 AM

In addition to adding an accumulator tank I would also add the pump silencing kit which consists of two hoses which will make adding the tank much easier. Both the tank and silencing kit are available on Amazon if there isn't a dealer near you. Also adding a piece of thick carpet under your pump and tank will cut way down on pump noise. Here are before and after photos of the tank and hose install but before adding the carpet pad. I made my own hoses just because I already had the parts, they are the big loops that help absorb vibration. Hope this helps.

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Cypressloser · 06-25-2017, 06:28 AM

First thing I would do is remove the pump, open it up carefully and check for debris (most likely small pieces of plastic from the fresh water tank installation) preventing the pump's membrane to seal properly and causing the system to slowly lose pressure.

BoDu · 06-27-2017, 08:09 AM

Before you go cracking open the fresh water system, check the screens on the faucets and see if they are clean. We have had enough junk catch in these screens to affect the flow rate of the system. Cleaning them eliminated the pulsing for us.

soonerdave · 06-27-2017, 07:31 PM

Water pumps work similar to an air compressor, when the pump builds enough pressure then the pressure switch stops the pump. When the pressure drops below a preset point the pump kicks back on. If you open a faucet all the way the pump can't build up enough pressure to shut off so the flow remains fairly constant. With a faucet partially open the pressure switch is sensing high and low pressures which in turn cycle the pump off and on, this is where the pulsations come from.

An accumulator tank absorbs the pulsation as the pump starts and stops at low flow which helps to smooth out the flow. You can change out the pump for one that senses flow (not cheap), install an accumulator tank (fairly inexpensive), or learn to live with the problem (free).

sikoriko · 06-28-2017, 01:04 PM

We had our water pump go out after two years. brand new. replaced it and did the rubber mount brackets, along with an accumulator. that made a big difference cant hear the pump running.

Mousemate1 · 06-29-2017, 07:26 PM

Hey all some of the water pumps are adjustable.
https://www.google.com/search?ei=A6h...k1.zelJqMdodDw
My cousin was able to adjust his and didn't have to add the accumulator.

SailorSam · 06-29-2017, 07:43 PM

If you decide to put in the accumulator tank. I recommend something like the 2 gallon Water Worker that you can get at many big box stores. I've seen a number of posts from people who got smaller RV tanks and ended up not being all that happy with them.

TJFogelberg · 07-03-2017, 06:45 AM

Having similar issues with my new RV. Does the pulsating harm the pump or shorten it's life? I need to have Tom's Mobile RV look at it. I am not a DIY when it comes to this although I will try the adjustment mentioned.

BFlinn181 · 07-03-2017, 09:10 AM

I don't have a pulsing water flow issue, so when I read soonerdave's explanation I couldn't believe that would be the issue. Further research proves him correct. If the pump had been built with a better pressure switch, that had high(off) and low(on) limits, the pulsing wouldn't happen. Problem is, the pressure switch is built into the pump and may not always be adjustable. An accumulator tank, using an enclosed air bladder, would smooth out the pulses and remedy the poor pressure switch limitations.

Another solution would be a 12" verticle piece of 2" plastic pipe, capped at the top. Installed in a 'T' fitting, this would also create an air cushion to absorb water pulses and eliminate the problem. Over time, the air pocket would be absorbed by the water and would have to be restored. This would require drainging the pipe or install an air valve to pump air into the chamber. An accumulator tank would be simpler.

Mounting the pump on flexible mounts would quiet the pump, but have no effect on reducing pulsing at a faucet.

soonerdave · 07-04-2017, 05:13 AM

Quote:

Originally Posted by TJFogelberg

Having similar issues with my new RV. Does the pulsating harm the pump or shorten it's life? I need to have Tom's Mobile RV look at it. I am not a DIY when it comes to this although I will try the adjustment mentioned.

The pulsing of the water is more of an annoyance to most people, it does absolutely no harm to your pump or your system. Most pumps don't have adjustable pressure switches so not really anything you can do on the pump itself. If the pulsation don't bother you then I would just leave it alone. I'm an engineer and like to tinker so I'm always messing with something! Keeps me off the streets, out of trouble, and the local hardware store in business!

Happy 4th of July to everyone!!! Be safe no matter where you are, remember our service men and women and police officers who keep us safe!!!

Grandpavan · 07-09-2017, 06:21 AM

I will probably just leave it along for now. I'm using the pump constantly right now as the Kant Leak valve is allowing water to leak into the fresh water tank when is the city water position. So I have to keep the fresh water tank filled and use the pump. I suspect that this is not a high end pump. Oh well.