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Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Yetch on November 30, 2020, 08:51:05 am

Title: House fresh water system
Post by: Yetch on November 30, 2020, 08:51:05 am
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
Title: Re: House fresh water system
Post by: Chuck & Jeannie on November 30, 2020, 08:57:50 am
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.amazon.com/SHURFLO-182-200-Pre-Pressurized-Accumulator-Tank/dp/B000N9VF6Q/ref=sr_1_18?dchild=1&keywords=small+water+pressure+tank&qid=1606744983&sr=8-18)

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

The Home Depot Logo (https://www.homedepot.com/p/Water-Worker-2-Gal-Pressurized-Well-Tank-HT2B/202846475)
Title: Re: House fresh water system
Post by: Yetch on November 30, 2020, 10:21:48 am
Ok, thanks.  Any idea as to the size of the tank?  I'm thinking a 2 gallon tank?
Mike
Title: Re: House fresh water system
Post by: wolfe10 on November 30, 2020, 10:25:15 am
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.
Title: Re: House fresh water system
Post by: Rudy on November 30, 2020, 10:26:10 am
Yes Sir, two gallon works fine for me.
Title: Re: House fresh water system
Post by: JohnFitz on November 30, 2020, 10:40:35 am
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.
Title: Re: House fresh water system
Post by: Yetch on November 30, 2020, 06:12:29 pm
Thanks all.  Got an AO Smith 2 gal tank and will attempt install tomorrow.
Mike
Title: Re: House fresh water system
Post by: Barry & Cindy on November 30, 2020, 06:27:09 pm
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 (http://amzn.to/3lodaEN) ) 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.
Title: Re: House fresh water system
Post by: Yetch on December 01, 2020, 02:56:16 pm
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
Title: Re: House fresh water system
Post by: Pamela & Mike on December 01, 2020, 03:12:59 pm
.  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
Title: Re: House fresh water system
Post by: Yetch on December 01, 2020, 04:57:20 pm
Ok.  Thanks.  Too easy install.  Set tank to 15 psi.  Water flows for 20 seconds or so before pump kicks in.
Mike
Title: Re: House fresh water system
Post by: Chuck & Jeannie on December 01, 2020, 06:47:39 pm
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.