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The Blue Tank

When I was working on winterizing my Foretravel, I came across a blue tank above the drain valves and below the water heater.
 
Anyone know what this is and what it does?
 
Thanks,
 
Trent

Trent and Jean Eyler
2000  U295  4003  WTFE  ISC  350
Build#5603 MC#17385

Re: The Blue Tank

Reply #1 –
That is your fresh water ACCUMULATOR.

Can't help with winterizing tips (we stay out of freezing temperatures).

But, occasionally you need to test it.  Momentarily push the shraeder valve.  If water comes out, the bladder is bad and you need to replace it.  With pressure water OFF and pressure bled off (open a faucet), it should be pressurized to 2 PSI less than pump cut in pressure.  So for most pumps 25-2=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: The Blue Tank

Reply #2 –
The accumulator tank comes after the water pump and before the water manifold.  The RV antifreeze that you pumped into the system will also be in the accumulator tank.  As Brett suggests an occasional test is a good practice.  Is you are running water in the kitchen sink for example, the pump should run then shut off, water continues to flow for a while and then the pump will come on for a bit then off again.  If the time between pump runs gets shorter then it is time to check the accumulator tank,

I'm glad to see all of your questions.  It tells me you are thinking about what you are doing and making sure you understand what is going on. That is a good way to approach all of the systems on your coach.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: The Blue Tank

Reply #3 –
Just replaced mine last week, noticed the pump "short cycling" so I checked the schraeder  valve and water came out. So ......bladder/diaphram  was shot. Bought one at Home Depot, took about an hour to replace. Shouldn't have taken that long but had difficulty getting the pipe fitting started while working in a blind spot. Problem was the existing tubing was too long and was bottoming out in the tank against the diaphram. May have been what punctured the original one. Removed the new tank and cut off about 1/2 " of the inlet tube and replaced tank on bracket. Had no trouble starting the pipe fitting the second time.
I have some photos but can't post them with this old I phone for some reason.

OK, here are some photos ....... had to put them on the laptop then upload

Here is the one I purchased from Home Depot .. 
Water Worker 2 gal. Pressurized Well Tank-HT2B - The Home Depot
Justin & Cathy Byrd
1995 U280 "Old Faithful"
36' Build #4673
C8.3 Cummins
Allison MD3060R 6 speed - retarder
Powertech 10KW  4cyl Kubota

Re: The Blue Tank

Reply #4 –
Quote from: FourTravelers –
I have some photos but can't post them with this old I phone for some reason.
Thanks for the tip about the tube possibly being too long.

If you email me the pictures, I can put them up for you,

Thanks,

Trent
eyler@cox.net
Trent and Jean Eyler
2000  U295  4003  WTFE  ISC  350
Build#5603 MC#17385

Re: The Blue Tank

Reply #5 –
Quote from: wolfe10 –
That is your fresh water ACCUMULATOR.

 it should be pressurized to 2 PSI less than pump cut in pressure.  So for most pumps 25-2=23 PSI.

It comes pre-pressurized  at 38psi therefore I released the pressure down to 20psi, works fine now.

Justin & Cathy Byrd
1995 U280 "Old Faithful"
36' Build #4673
C8.3 Cummins
Allison MD3060R 6 speed - retarder
Powertech 10KW  4cyl Kubota

Re: The Blue Tank

Reply #6 –
Yup, proper PSI depends on pump cut-in pressure.  Since these are also used in home systems, very understandable that they are pre-pressurized higher than proper for an RV system.
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: The Blue Tank

Reply #7 –
Yep, just replaced our pump and accumulator mid Oct before leaving for the winter. I followed Brett Wolfe's instruction on testing the tank and got a steady stream of water. Replaced the pump and tank. Home Depot in our area couldn't get the tank for about 6 weeks.
Ordered the whole assy from Amazon ($433) and had it in 2 days. Should be good for another 10-15 years.
Dick & Sue
'99 U320, 36'
2015 F150 4x4 Supercrew
M & G with brakeaway system
Blue Ox Avail 10,000# tow bar
Grosse Ile, Mi.

Re: The Blue Tank

Reply #8 –
Quote from: Dick & Sue –
Home Depot in our area couldn't get the tank for about 6 weeks.
Ordered the whole assy from Amazon ($433) and had it in 2 days. Should be good for another 10-15 years.

Trent
I purchased the WaterWorks tank from Lowes but discovered I would need to tinker a little to make it work. The two tanks are not the same size. The OEM water port is 1/4" NPT and the WW tank is much larger. The OEM has two threaded rods/bolts on the bottom of the tank (Shown in the photo with protective rubber caps over the threads) These fit into the plastic base and makes securing the tank much easier. A lot of members have bought the much cheaper WW tank and it works perfectly. I simply did not want deal with cutting pex and adding fittings. I returned the WW tank to Lowes.
I found the OEM tank only at ABS Alaskan  Alternative & Renewable Energy - ABS Alaskan. I ordered only the tank (not in stock) in July and received it early August. It took about 3 or 4 weeks. $165.00. YMMV
Ed and Michele
2000 U295  36'  (Build #5600)
8.3 ISC 350HP.
2012 Jeep Grand Cherokee (Toad)
2001 Lance Truck Camper (Sold)
2001 Lazy Daze (Class C). RK Floor Plan (Sold)

Re: The Blue Tank

Reply #9 –
Quote from: FourTravelers –
Quote from: TulsaTrent –
Thanks for the tip about the tube possibly being too long.

Problem was the existing tubing was too long and was bottoming out in the tank against the diaphram. May have been what punctured the original one. Removed the new tank and cut off about 1/2 " of the inlet tube and replaced tank on bracket. Had no trouble starting the pipe fitting the second time.

Trent, I think you will find we (2000 U295) don't have a "tube".  I don't and as we have pointed out to each other a few times our build numbers are very close.
Ed and Michele
2000 U295  36'  (Build #5600)
8.3 ISC 350HP.
2012 Jeep Grand Cherokee (Toad)
2001 Lance Truck Camper (Sold)
2001 Lazy Daze (Class C). RK Floor Plan (Sold)

Re: The Blue Tank

Reply #10 –
I looked at the instructions for the one at Lowe's (or HD) and it said it could only be installed vertically! That would require replumbing. Hopefully, mine will just spit air; no water.
 
Trent
Trent and Jean Eyler
2000  U295  4003  WTFE  ISC  350
Build#5603 MC#17385

Re: The Blue Tank

Reply #11 –
The water works tank from Home Depot was an exact fit of the one I removed. We have a 95 U280. No bolts used, just mounted to a bracket with two large "plumbers" straps. One 1/2 " pipe nipple on the back side. It has a diaphram so it should not matter if vertical or horizontal mounted.

Trent, check yours and if it mounts with two straps ... It should work.
Justin & Cathy Byrd
1995 U280 "Old Faithful"
36' Build #4673
C8.3 Cummins
Allison MD3060R 6 speed - retarder
Powertech 10KW  4cyl Kubota

Re: The Blue Tank

Reply #12 –
I replaced mine several years ago with a tan 2ga. tank for hot water on advice from my son in law who is a plumber, it uses different
 bladder material.
The selected media item is not currently available.Bill&Doris 97 U270 36'
University of Parris Island Class of 66
Semper Fi  Build# 5174 MC#17094
 

Re: The Blue Tank

Reply #13 –
Quote from: Bill Willett –
I replaced mine several years ago with a tan 2ga. tank for hot water on advice from my son in law who is a plumber, it uses different
 bladder material.
I would like to replace mine with a larger tank but there just isn't any room. Had a seven gallon tank in our fiver and liked it as the water pump didn't cycle as much. Unfortunately not enough extra space in the coach anywhere in the line that I can see in any case.

Roland
1993 U280 4341
2010 Jeep Liberty
The Pied Pipers