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Topic: Water Pump Cycling (Read 686 times) previous topic - next topic

Water Pump Cycling

When I bought my coach I had to replace my waterpump. I replaced it with a new sureflow unit. The original pump had the accumulator tank etc. Sureflow said I wouldn't need it anymore, but I still have it hooked up in the system.
My question is everytime ass oon as I turn on my water my pump runs and it cuts off as soon as I turn it off. But,isnt the accumulator supposed to kind of regulate the cycling of the pump, I hear my pump when it turns on inside the coach,i'd like it better if it wasn't as loud but I have been wondering why it doesn't let me run a little water before the pump turns on, Is there a adjustment to slow down the cycling?
91 GV U300 Unihome 40' Build 3811
6V92TA Detroit

Re: Water Pump Cycling

Reply #1 –
There was a thread just a couple weeks ago on this issue

The Blue Tank

You can test your accumulator tank to see if it is OK.  If the accumulator tank is still installed and the pump runs every time you turn on the water you probably have a bad blue tank.

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

Re: Water Pump Cycling

Reply #2 –
Yup, you need to verify that your accumulator does not have a bad diaphragm.

Touch the shraeder valve with a screwdriver or other tool that will just activate it.  If water comes out, the accumulator is bad. Replace it.

If air comes out, you may just need to repressurize:

Turn off pump, shore water off. 

Open a faucet to release pressure.

Add air (bike pump works fine) to 2 PSI below CUT-IN PSI.  If OE Shureflo pump 23 PSI.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Water Pump Cycling

Reply #3 –
Quote from: wolfe10 –
Yup, you need to verify that your accumulator does not have a bad diaphragm.

Touch the shraeder valve with a screwdriver or other tool that will just activate it.  If water comes out, the accumulator is bad. Replace it.

If air comes out, you may just need to repressurize:

Turn off pump, shore water off. 

Open a faucet to release pressure.

Add air (bike pump works fine) to 2 PSI below CUT-IN PSI.  If OE Shureflo pump 23 PSI.
Thanks Ya'll water came out I'll get a new one !
91 GV U300 Unihome 40' Build 3811
6V92TA Detroit

Re: Water Pump Cycling

Reply #4 –
When I replaced my original water pump I bought one that didn't require a tank but as you mentioned it came on every time I used the water. I bought a new blue tank, about $50 at Lowes and also installed the flexible water line mentioned in other threads here and I couldn't be happier. I can barely hear the pump when it comes on in it doesn't come on very often.

 I highly recommend the accumulator tank with flexible hose even with the use of one of the new demand pumps, particularly in the older coaches where there is little sound attenuation in the original system.
The selected media item is not currently available.Kent Speers
Locust Grove, OK
1993 U300 SSE 40' (Restored at FOT 2009) Build 4323
720 watts Solar
6V92TA DDEC Silver Engine
2014 Subaru Outback

Re: Water Pump Cycling

Reply #5 –
Kent that's exactly what mine does. The new pump doesn't require a tank but it is loud and runs everytime you open a faucet. Quieting it down would be great. My Home depot is showing one in stock about 40 bucks I'm going down in a bit after I finish coffee and wasting time on puter!! Did you have to change the air charge in your new tank to a different PSI?
91 GV U300 Unihome 40' Build 3811
6V92TA Detroit

Re: Water Pump Cycling

Reply #6 –
With some of the box store tanks, you will need to buy a reducer, as the outlet threads are larger-- no big deal.

Be sure to check and re-set PSI to 2 PSI less than your pump's CUT-IN PSI.  So, for the OE Shurflo set it at 23 PSI.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Water Pump Cycling

Reply #7 –
Thanks Brett It is a  new sureflo pump, I'll post results later. 
91 GV U300 Unihome 40' Build 3811
6V92TA Detroit

Re: Water Pump Cycling

Reply #8 –
All fixed ,new tank, and insulated water lines all down there, adjusted bladder psi to 20. 2/3 quieter than before and pump waits a while to turn on. Thanks for the help and info, This forum rocks!!! ^.^d
91 GV U300 Unihome 40' Build 3811
6V92TA Detroit

Re: Water Pump Cycling

Reply #9 –
Quote from: stump –
  This forum rocks!!! ^.^d

Yup, our pumping system is quiet as all getout since Papa Brett worked on it in 02. Only drawback? It's easy to leave on after dry camping!
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
Previous: 1983 Airstream 310 turbo diesel, 1979 Airstream 280 turbo diesel
                                      Build # 4297
                                      PNW natives
                      Home base:  'Cactus Hug' (Ajo, Arizona)
                        DW Judy & Chet the wonder dog
                        Full-Timers 'Sailing the asphalt sea'

Re: Water Pump Cycling

Reply #10 –
My accumulator was bad but replacing it didn't solve the problem of pump failing to cycle off. The pressure is low and I see no leak anywhere. Guess I need a new pump. BTW, Home Depot sells a direct nearly identical accumulator to the stock unit for about $40...no reducer needed, at least on mine. 
Dwayne Keith
1992 U240
3116/MD3060

Re: Water Pump Cycling

Reply #11 –
Dwayne,

While it could be a water pump, could also be a check valve or an air leak into the suction side of the pump. Only other cause I can think of is a faulty pressure switch on the pump.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020
 

Re: Water Pump Cycling

Reply #12 –
I installed a variable speed pump, but did not remove the accumulator. Instead, I pumped the accumulator to 90psi with no water pressure in the system. It absorbs the volume increase when the hot water heater heats the water.

The variable speed pump, along with flexible lines (mainly on the output) was one of the best replacements I've done. The original pump from 1998 was still working, but it was dripping. When i did the pump swap, I also installed the 3way valve to suck anti-freeze into the pump to make winterizing super fast. Also installed water heater bypass. I don't trust blowing lines out.

I had to replace my pressure tank recently as the bladder blew, but I got one from lowes for 30bux.
1998 U270 34'