Skip to main content ↑ ↓
Topic: Variable speed Water Pump Pulsing (Read 1381 times) previous topic - next topic

Variable speed Water Pump Pulsing

My new to me '03 U320 has a 55AQUAJET-ARV house/fresh water pump. The pump date of manufacture is 05/12.

While in the shower, and with no other demand on the pump, the water is pulsing. As if it reaches full pressure, pauses, starts again.

I haven't dug deep behind the fiberglass panels to see if there is an accumulator.

With the pulse of the water pressure, the temperature of the water changes from hot(high pressure), to Cold(low pressure). Needless to say, very uncomfortable shower.

Those of you that have had a similar experience, did replacing the pump solve the problem?

Thanks Much,
Jay Darst
2003 4020 U320 PBDS Build# 6147
Previously: 1985 Bluebird Wanderlodge PT40
Rehobeth, AL

Re: Variable speed Water Pump Pulsing

Reply #1 –
If you have an accumulator tank that has a failed internal bladder the pump will run more frequently.

You may also have some restrictions in the hot water lines. This is common, hot water deposits calcium and other minerals much faster than cold. We flushed out our hot water lines last summer with vinegar which loosened up lots of crud and then spent a bunch of time cleaning every possible catch point.  Better water flow and pressure in the hot side now.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Variable speed Water Pump Pulsing

Reply #2 –
I did the vinegar wash last year too.  Here's the thread where I posted how and my results:

Hot water gets hotter and cooler while taking a shower

Does it pulse quickly, a few times a second or slowly?  If it's quickly, I've seen this happen if there was air in the lines to other faucets...for instance after I've drained the fresh tank and let all the faucets run dry.  If that's the issue, run all the faucets to make sure all the air is out of the system.

If it's going slowly, mine did this when I added my new shower head.  This was due to the restrictor in the shower head.  The pump would get up to pressure and shut off before the shower head could flow enough to drop pressure and make it turn on again.  Took the head off the hose, pulled out the plastic restrictor with three small holes in it and now have proper flow out of the shower...and the slow pulsing stops as now the pump runs full time to keep up with the demand.
Keith
2003 U320 38' #6197

Re: Variable speed Water Pump Pulsing

Reply #3 –
with regard to the water pressure up and down... with a faucet on, the fresh water pump cycles to full pressure, stops, pressure drops over a 2second period, pump starts again, and repeat.

With that, I am confident that there is an accumulator somewhere. I want to remove the accumulator from the system. The water pump is a variable speed pump that should run continuously while water spigot is open, making speed adjustments to maintain appropriate pressure/volume.

In my previous coach, I removed the 1 speed on/off pump and accumulator and installed a variable speed pump. Worked perfectly for about 15 years(then sold the Bird).

2003 U320 PBDS 40'- does anyone know where the accumulator is located?

I will be introducing vinegar next. Did anyone confirm that it is/is not ok to include the aqua hot in the vinegar procedure?

Thanks again, sure appreciate all the info available here!
Jay Darst
2003 4020 U320 PBDS Build# 6147
Previously: 1985 Bluebird Wanderlodge PT40
Rehobeth, AL

Re: Variable speed Water Pump Pulsing

Reply #4 –
You want to flush with vinegar just like winterizing the coach.  Turn off the water supply to the under-sink filter. Drain all the water lines, blow out at low pressure if you can. Use your water pump to pump vinegar into all of the water lines, hot and cold. Open one faucet at a time, hot then cold, till vinegar starts out.  Do the same with the water line drains. And the toilet, shower and service faucet.

If some gets in the drains it won't hurt.  Leave the shower head in a small bucket (maybe a cottage cheese container) with some vinegar in the bucket to soak the head.

If you spill vinegar in the shower rinse it down.

Turn on the AH, electric is fine, diesel is much quicker.  After one cycle or when it is hot turn the AH off.  Open each hot faucet till some hot vinegar comes out.  Let it sit overnight.  Then hook up to fresh water and flush all the lines well. Open and close all valves, shower, service faucet, toilet, line drains until clear water.  Hot vinegar can stain some things so rinse carefully.  It can also kill grass and weeks.  We saved all we could and sprayed weeds in the driveway.

The check everywhere there might be a faucet screen and clean them.  This process will loosen up a lot of crud.  we did the shower and the bathroom faucet twice.

Uses 6 or 7 gallons of ordinary household vinegar.


Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Variable speed Water Pump Pulsing

Reply #5 –
Quote from: JDarst –
with regard to the water pressure up and down... with a faucet on, the fresh water pump cycles to full pressure, stops, pressure drops over a 2second period, pump starts again, and repeat.

With that, I am confident that there is an accumulator somewhere. I want to remove the accumulator from the system. The water pump is a variable speed pump that should run continuously while water spigot is open, making speed adjustments to maintain appropriate pressure/volume.

2003 U320 PBDS 40'- does anyone know where the accumulator is located?
My 2003 U320 PBBS 38' does not have an accumulator.  On this page, it shows that maybe there was one originally (part number also provided):  Foretravel Motorhome 2003 Foretravel U320 part numbers | All Things Foretravel

Did you check the shower head for a restrictor?  Mine works like you said...with any one faucet running, the pump builds pressure, shuts off and when the pressure drops after a few seconds, the pump starts again and repeats the process.  With two faucets running, the pump runs continuously.  With no restrictor in the shower head, the pump runs continuously when the shower is flowing.
Keith
2003 U320 38' #6197

Re: Variable speed Water Pump Pulsing

Reply #6 –
2000-320
Mine pulses like Jays. Good water flow- just pulsing. I added air to the accumulator tank- no change. Weird

Re: Variable speed Water Pump Pulsing

Reply #7 –
The Flo-jet accumulator was a smaller black plastic tank right next to the pump. I installed a shurflo water pump and never had a problem with it.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Variable speed Water Pump Pulsing

Reply #8 –
Ok 😁
Here it is...
I flushed the Aqua Hot and, thru it's drains, it expelled about a 1/4 cup of crystallized debris.
When flush the fresh water tank, it expelled about the same. All day adding water and draining thru the factory installed drains into a 5 gallon bucket with 3/4 it cut off, and a garden hose fitting inserted about mid tween the bottom and the shortened top. The debris would sit in the bottom of the bucket while the water drained out thru the fitting and garden hose.
I also removed the flow restrictor from the shower head (thank You Keith)
The shower was awesome! Had great pressure and volume, dam near too much if that's even possible.
The pump never cycled.
I reached out and turned the bathroom sink faucet on (I had already put the restrictor/ diffuser in vinegar) and the pump sped up, no loss of pressure or volume 🎉🎉
Bottom line, I think the Remco 55Aquajet-ARV, with its variable speed and by-pass valve were compromised with crystallized contaminates which did not allow the by-pass valve to open which would cause the pump to reach its full pressure, stop, then the immediate pressure drop would restart the variable speed pump. With all the flushing today, the debris was exhausted out the drain. The pump performed as it should. The pressure was smooth and consistent from a slightly open fixture to 2 fixtures wide open.
Removing the restrictor in the shower head was the icing on the cake.
I thought my Bluebird had a great shower...This Foretravel's pump has higher pressure and volume, coupled with no restrictor in the shower head is THE best ever.
I no longer believe there to be an accumulator in my rig, not searching any further.
Jay Darst
2003 4020 U320 PBDS Build# 6147
Previously: 1985 Bluebird Wanderlodge PT40
Rehobeth, AL

Re: Variable speed Water Pump Pulsing

Reply #9 –
With that amount of gunk coming out of the system you may need to plan on doing another acid wash in about a month.  After that you may have to think about doing it on an annual basis but that will depend on the hardness of the water in the area that you travel. Case in point even with our water softener if we are at our place out in SE New Mexico we will have to do an acid wash after a 4 month stay due to the hard water.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Variable speed Water Pump Pulsing

Reply #10 –
Kind of piggybacking on this topic, but my intention is to replace water pump.  (shurflo4008)  with a new 4048 to increase my pressure and water flow. If I just leave the water pump switch off am I safe in changing over the power wires from one unit to the other, or is there a breaker that I have to turn off?
Peter    Alberta Canada
'98 U320 40'  Build 5359 M11 450 HP, Aqua hot, Blu Ox

Re: Variable speed Water Pump Pulsing

Reply #11 –
Just leave the switch off, you will fine.
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: Variable speed Water Pump Pulsing

Reply #12 –
Thanks for the info!
Peter
Peter    Alberta Canada
'98 U320 40'  Build 5359 M11 450 HP, Aqua hot, Blu Ox
 

Re: Variable speed Water Pump Pulsing

Reply #13 –
Quote from: erniee –
2000-320
Mine pulses like Jays. Good water flow- just pulsing. I added air to the accumulator tank- no change. Weird
Could be that your accumulator tank bag is bad.  When you add air have you put a pressure gauge on it to see if it is holding air?  Another way to find out if bag is bad is open up shredder valve by sticking something in the center. If water comes out, you have a bad bag.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago