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Fresh Water Pump

What is the best water pump to use for pressure on the fresh water system without having to use an accumulator tank.
John M.
John & Carm Morales
1999, U320, Build 5559, 3600 CAI, Cummins M11 450 HP
"We travel not to go anywhere, but to just go.  We travel for travel’s sake.  Our great desire is to move."


Re: Fresh Water Pump

Reply #1
John,we replaced ours with a Shurflo,will get the model but I talked to their customer service and there is no need for a tank,ours
works fine.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Fresh Water Pump

Reply #2
We also went with SureFlo. AquaJet is also a good choice.
SureFlo
jor
97 270, 34'
Previous:
93 225, 36'
99 320, 36'
95 300, 40'


Re: Fresh Water Pump

Reply #4
Just replaced mine with a new Remco Aquajet 5.3 GPM unit.
Previous coach - 2007 Phenix 45'

Re: Fresh Water Pump

Reply #5
Why would you not want an accumulator tank??  They really do save a lot of cycles on the pump, and that is what wears out a pump sooner than necessary.  I put a larger than original in our coach and it really cuts a lot of wear and tear off of the pump.  Have a great day  ----  Fritz
Fritz & Kathy Johnson
1991 36'

Re: Fresh Water Pump

Reply #6
We have a sure flow with no tank but I ordered a tank to add on (haven’t done it yet) to avoid the surging of the pump on low flow.   I don’t like the system with no tank.
Rick & Rhonda
2003 U320 4220  Build #6199
Was
91 36' GV 300 Caterpillar, 92 40' U280 300 Cummins, 97 36' U295 300 Cummins, 2002
U320 450 Cummins
(Guess we're hooked)



Re: Fresh Water Pump

Reply #7
Reply to reply #5,less fittings,less leaks.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Fresh Water Pump

Reply #8
We have the Shurflo 4008 and later added a small black plastic Shurflo accumulator with a couple of flexible hose connections. Pump and accumulator is not fastened down. Seemed that a small accumulator helps, but is not required.

Re: Fresh Water Pump

Reply #9
Agree 100% with Barry.  I installed a new 4008 pump, and removed the blue pressure tank.  Tried it for a while, but not happy with the way pump had to run every time, the instant a water faucet was opened.  Reinstalled the blue tank - now much happier.  The pump works fine either way, but operation seems to be much more "relaxed" working in tandem with a pressure tank.  Just a subjective opinion, of course.
Chuck, Jeannie & Bella the MalChi
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Kia on a Kar Kaddy SS
I may suffer from the Dunning-Kruger effect, but I seriously doubt it...

Re: Fresh Water Pump

Reply #10
One other thought about pressure tanks.  They may provide a secondary function of damping the pressure fluctuations in the hot water tank caused by the heating cycle.  I have seen reports of RV owners having a problem with hot water dribbling out of the pressure relief valve on the water heater.  Seems this can happen when the water heater is 100% full and there is no "air gap" in the tank.  With a pressure tank, you probably don't need to worry about maintaining the air gap in your water heater.  One less thing to keep you from kicking back and enjoying a cold one!

Go to the link below, and read down to the bottom of the very helpful article, where "air gap" is explained:

RV Water Heater Troubleshooting - Simple Maintenance Will Save You Money! -
Chuck, Jeannie & Bella the MalChi
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Kia on a Kar Kaddy SS
I may suffer from the Dunning-Kruger effect, but I seriously doubt it...

Re: Fresh Water Pump

Reply #11
May be a good idea to have a spare relief valve handy,they are not made to be opened and closed alot and may not reseal.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Fresh Water Pump

Reply #12
But, they can be found in most hardware stores.  Not sure they would make my "top 100 parts" list.
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: Fresh Water Pump

Reply #13
I installed the new style Surflo. Added the tank back (PO took it out) Granted the pump ran less, but when it ran, it ran longer then just the short squirts when flushing.
Took the tank back out.Works way better IMHO.
Home depot sells the tank with no mounts $39.00. I have one if someone needs one.
Chris
Chris and Tammy White  CDA Idaho
1997 U295 36' 3126 Cat 300 HP Build # 4998 
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: Fresh Water Pump

Reply #14
But, they can be found in most hardware stores.
When I went hunting for a replacement valve, the local "usual suspect" big box stores did not stock a valve with 1/2" pipe thread.  Seems most residential hot water heaters use a larger thread size.  Having one on hand in a emergency situation may save you some time...or not...depending on local inventories.

0121325 - Watts 0121325 - 1/2" LF1XL-4 T&P Relief Valve, Lead Free (150 psi)
Chuck, Jeannie & Bella the MalChi
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Kia on a Kar Kaddy SS
I may suffer from the Dunning-Kruger effect, but I seriously doubt it...

Re: Fresh Water Pump

Reply #15
I'm currently running a tank with my pump but I'm not happy with the pressure I get when opening the faucets.  Also pressure gets very low before pump kicks in.  I'll have to check the tank air pressure and make sure it's not leaking.  Everyone thanks for the input.  Maybe I'll keep the tank and upgrade the pump.  To be continued.
John M.
John & Carm Morales
1999, U320, Build 5559, 3600 CAI, Cummins M11 450 HP
"We travel not to go anywhere, but to just go.  We travel for travel’s sake.  Our great desire is to move."


Re: Fresh Water Pump

Reply #16
Short cycling electric motors can build heat in the windings with inadequate run time. I replaced my accumulator tank because the bladder had a leak and it was waterlogged and not accumulating. As for the water heater the check valve on my constant speed pump won't allow for thermal expansion when the water heater starts up cold if the accumulator is waterlogged or way too small, and hopefully leaks out the relief valve. Variable speed pumps may not need or have a check valve as there is no accumulator (but my guess is it has one). Said another way if there no check valve on a variable speed pump with an accumulator the pump motor could be made to spin backwards as the accumulator now starts to push the water back to the fresh water tank and really pull inrush amps if it's still coasting backwards. You paid to pressure up the system. I kinda prefer the  simple constant speed stupid pump/accumulator for these reasons. Just my 2 cents. Spare relief valve may make a trip more pleasant if it fails due to a check valve, waterlogged accumulator, closed inlet valve. And never exercise the relief valve as prudent, on a trip or if you don't have a spare valve. Cause when exercised they typically fail open. Most home or building inspectors won't touch releif valves for this reason.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Fresh Water Pump

Reply #17
We use a small plastic Shurflo accumulator, bigger may not be as good. Also we buy Atwood part Temp-Press release valve. Pump worked ok without accumulator.

Re: Fresh Water Pump

Reply #18
Shurflo 4048 & 4008 are NOT variable speed. They do their low flow control feature with a spring loaded internal bypass that flows out back to in. We also plumbed Temp-Press valve to outside of compartment through the floor hole that the hot/cold/fresh dumping goes to the ground.at the hot/cold/fresh dumping goes to the ground.

Re: Fresh Water Pump

Reply #19
Barry that makes sense tiny accumulator to help dampen pump pressure pulses and absorb the expansion from the water heater would be a very desireable feature. Bypass would allow tighter control pressure regulation. Obviously it has a check valve on the inlet. Mistook varible output flow via bypass, as variable rpm.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Fresh Water Pump

Reply #20
Also we buy Atwood part Temp-Press release valve.
Available from Amazon for a better price than the link I posted above (Reply #14).

Amazon.com: Atwood 91604 1/2" Relief Valve: Automotive
Chuck, Jeannie & Bella the MalChi
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Kia on a Kar Kaddy SS
I may suffer from the Dunning-Kruger effect, but I seriously doubt it...

Re: Fresh Water Pump

Reply #21
John,

Suspect you already know this, but to check/pressurize accumulator pressure:

Turn off pump and shore water.
Open faucet to bleed off pressure
You will need a small screwdriver, standard automotive tire gauge and either bicycle air pump or other air source.

Remove the plastic cap from the tank valve stem.
Momentarily touch the tip of the screwdriver to the center stem-- just long enough to verify that you are getting AIR, not water out.  If water, the accumulator is dead and needs to be replaced.

Correct PSI is pump CUT-IN PSI less 2 PSI.  So for the old pumps with 25 PSI cut-in PSI, 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: Fresh Water Pump

Reply #22
Thanks Brett!  Will check the tank.
John M.
John & Carm Morales
1999, U320, Build 5559, 3600 CAI, Cummins M11 450 HP
"We travel not to go anywhere, but to just go.  We travel for travel’s sake.  Our great desire is to move."


Re: Fresh Water Pump

Reply #23
All that’s needed is a vertical chamber in the pressure side of the line. A 3 in by 6in pipe with a tight cap will soften the pump pulse action. The pump may last  longer and will make less noise and the shower will feel smoother.

Re: Fresh Water Pump

Reply #24
Yup, a homemade accumulator.
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