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Topic: House fresh water system (Read 781 times) previous topic - next topic

House fresh water system

Just switched over to internal water supply, and I noticed that the water pump now comes on immediately when I turn on a water source, rather than a delay allowing the accumulator to empty before pump starts up.  So I am assuming that the accumulator tank has failed and not holding pressure.  Does that sound about right?  Any suggestions as to the size and source for a new tank?
Thanks, Mike
Mike Brady
'97 U320 SE. #5137
'13 Honda Fit
Willow Springs, MO

Re: House fresh water system

Reply #1 –

If you can get at the accumulator tank and the schrader valve on one end, you can "test" the tank.  Push in on the valve pin and see what comes out.  Water?  Tank is toast.  Air?  Try carefully adding some pressure (put about 20 psi in to see if that helps).

Tanks are available online, or at Lowes and Home Depot.  Search the Forum for ideas and recommendations.

Amazon.com: SHURflo 182-200 Pre-Pressurized Accumulator Tank,Black: Automotive

https://www.lowes.com/pd/A-O-Smith-2-Gallon-Vertical-Pressure-Tank/1000565589

The Home Depot Logo

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1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: House fresh water system

Reply #2 –
Ok, thanks.  Any idea as to the size of the tank?  I'm thinking a 2 gallon tank?
Mike
Mike Brady
'97 U320 SE. #5137
'13 Honda Fit
Willow Springs, MO

Re: House fresh water system

Reply #3 –
Yes, correct accumulator PSI is pump cut in PSI minus 2 PSI.  So, for many with 25 PSI cut-in, 23 PSI.

It is set with pump off and a faucet open to bleed off pressure.
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: House fresh water system

Reply #4 –
Yes Sir, two gallon works fine for me.
Rudy Legett
2003 U320 4010 ISM 450 hp
2001 U320 4220 ISM 450 hp
1995 U320 M11 400 hp
1990 Granvilla 300 hp 3208T
Aqua Hot Service Houston and Southeast Texas

Re: House fresh water system

Reply #5 –
Mike,
I wouldn't worry about the size too much; you were OK with how the old one worked, right?
The easiest thing is to replace what you have for one with the same size and connection.

My old one was above the water pump and that area was very tight.  I installed a 2 gallon Home Depot unit under my sink with a long flex hose.  It fits loosely in a 45 degree nook where I can just pull it out onto the floor to check it.  The accumulator can be installed anywhere in the cold water circuit.
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho

Re: House fresh water system

Reply #6 –
Thanks all.  Got an AO Smith 2 gal tank and will attempt install tomorrow.
Mike
Mike Brady
'97 U320 SE. #5137
'13 Honda Fit
Willow Springs, MO

Re: House fresh water system

Reply #7 –

For those with a Shurflo internal bypass pump (4008,4048) just a small plastic Shurflo accumulator ( Amazon.com: SHURflo 182-200 Pre-Pressurized Accumulator Tank,Black: Automotive ) is fine. No need to take up a lot of space with a big metal accumulator. These pumps work ok without an accumulator.

These accumulators & pumps do not need to be fastened down and should be installed with ball valves on either end and hoses with slack.

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Re: House fresh water system

Reply #8 –
I'm a bit confused.  My Shurflow 4008 water pump has a Shut Off pressure of 55 psi, 3 gpm.  Not sure what Continuous pressure is not listed.  Brett says to set tank pressure at 2-3 psi below pump pressure.  MOT says to set tank pressure at 10 psi.  What is the relationship of the pump to the pressure in the pressure tank? 
Thanks for the help.
Mike
Mike Brady
'97 U320 SE. #5137
'13 Honda Fit
Willow Springs, MO

Re: House fresh water system

Reply #9 –
Quote from: Yetch –
.  What is the relationship of the pump to the pressure in the pressure tank? 

The amount of water that can be used out of the pressure/volume tank.

If you set the pressure in the tank (this is on the back side of the diaphragm) at only 10 psi you will only be using about 1/4 of the tank, causing the pump to cycle more often.

Mike
Pamela & Mike 97 U 320

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

Re: House fresh water system

Reply #10 –
Ok.  Thanks.  Too easy install.  Set tank to 15 psi.  Water flows for 20 seconds or so before pump kicks in.
Mike
Mike Brady
'97 U320 SE. #5137
'13 Honda Fit
Willow Springs, MO
 

Re: House fresh water system

Reply #11 –
Quote from: Yetch –
Brett says to set tank pressure at 2-3 psi below pump pressure.
If you read Brett's comment carefully, you will see he said "2 psi below pump CUT IN pressure"...or about 23 psi for the average pump.

This is the same "rule of thumb" as for household pressure tanks (which we have).  Our water well pump cycles between 40 and 60 psi, so I set the pressure tank (bladder tank) at 38 psi.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"