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Topic: Tank pressure won't build (Read 313 times) previous topic - next topic

Tank pressure won't build

One of my tank guages wont build past 25 psi. (One on the left builds to 120.psi) I just replaced a pressure protection valve that was leaking bad and thought that would fix my low psi reading but it didn't.
After the air system builds to full pressure and I shut down engine I don't hear any bad leaks. Could this be a bad air sending unit on the tank?
Dylan and Aimee
2001 U320 4013
Unit# 5896
450 HP/IFS
 

Re: Tank pressure won't build

Reply #1 –
Your coach has the infamous blue or some other color box that goes wonky.

Air Pressure won't build
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Tank pressure won't build

Reply #2 –
With only 25psi in the tank, the beeper in the dash should still be going off for low air pressure.  Is it?
Keith
2003 U320 38' #6197

Re: Tank pressure won't build

Reply #3 –
Quote from: WS6_Keith –
With only 25psi in the tank, the beeper in the dash should still be going off for low air pressure.  Is it?
Yes, and the red light is on.
Dylan and Aimee
2001 U320 4013
Unit# 5896
450 HP/IFS
 

Re: Tank pressure won't build

Reply #4 –
If you have a threaded water drain valve on both tanks, you should be able to connect a small inexpensive pressure gauge to the tank and read the actual tank pressure.

If it agrees with your dash gauge, you have a mechanical problem.  Either air pressure isn't reaching the tank, or it is leaking out.

if your dash gauge is lying to you, then it's a sensor problem.  See craneman's post.
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: Tank pressure won't build

Reply #5 –
My "blue box" hasn't entirely failed but my dash gauges are notoriously inaccurate and I have been through two of the pressure senders on the air tanks (which are ridiculously overpriced and only available at Summit Racing as near as I can tell).  I like redundancy so I installed two VDO mechanical air pressure gauges in the dash in addition to the OEM electronic pressure gauges.  Gives me peace of mind and way more accurate data.  For the same reason I also run the Scan Gauge D to redundantly monitor the other gauge functions.
George Mann
2002 U320 #5934
2017 Rubicon
2013 BMW GS
Waterford MI

Re: Tank pressure won't build

Reply #6 –
Keep in mind that there is a regulator between your rear and front air tanks that could fail. If I recall correctly, the airline on your coach comes off the front tank, that could be an easy way to determine if air is getting into the front tank or not
1987 Grand Villa ORED
2001 U320 4010

Not all that wander are lost... but I often am.