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Topic: pneumatic check valves, pressure protection valves and aux compressor replumbing (Read 567 times) previous topic - next topic

pneumatic check valves, pressure protection valves and aux compressor replumbing

I've posed this question before and I don't think I ever received any responses.  I'm planning to overhaul my air tanks/fittings to address some leaks and some strange behavior.  I've purchased new pressure protection valves because when I tested my system by bleeding air off of the aux. air connection both front and rear air tanks dropped below 40psi and continued to allow air to pass (at a slow rate).  My understanding is that the pressure protection valves should stop delivering air to the aux port below 60 or 65 psi.  These are the pressure protection valves that I have purchased:

Haldex 1/4" NPT Pressure Protection Valve

Since I have to disassemble all of the fittings past the pressure protection valves, there are also some check valves so I'm going to replace them too.  In my search for parts I have found this style of check valve:

Haldex KN23080 Air Brake Reservoir Check Valve + Cross Reference | FinditParts

and also this style of check valve:

https://www.grainger.com/product/55RT94?gucid=N:N:FPL:Free:GGL:CSM-1946:tew63h3:20501231

Obviously there is a significant price difference but also a significant size difference.  My question is, what are the practical differences between these two check valves and where would one be more appropriate than the other?  I know the general consensus will be to buy the expensive ones but I'm interested to hear other's experience with these.  For what it's worth, the original check valves at the front and rear tanks look like the larger ones although I have found that all of the check valves in the auxillary (HWH) compressor lines are the latter style including the one between the compressor and the pressure switch and also on both slide manifolds.
George Mann
2002 U320 #5934
2017 Rubicon
2013 BMW GS
Waterford MI

Re: pneumatic check valves, pressure protection valves and aux compressor replumbing

Reply #1 –
On our much older coach, the check valve at the inlet of front and rear brake tanks is a Haldex KN23000.

Part Number Collection

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: pneumatic check valves, pressure protection valves and aux compressor replumbing

Reply #3 –
Quote from: Geodmann –
I've posed this question before and I don't think I ever received any responses.  I'm planning to overhaul my air tanks/fittings to address some leaks and some strange behavior.  I've purchased new pressure protection valves because when I tested my system by bleeding air off of the aux. air connection both front and rear air tanks dropped below 40psi and continued to allow air to pass (at a slow rate). 

Since I have to disassemble all of the fittings past the pressure protection valves, there are also some check valves so I'm going to replace them too.

an '02 should have the same setup as an '03 and I believe the check valves Mike mentions are the same as were in our '03.

Here's the parts manual for reference  The selected media item is not currently available.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: pneumatic check valves, pressure protection valves and aux compressor replumbing

Reply #4 –
I am getting message that the file is corrupt.  I downloaded a second time and same message.

The KN323080 is 1/4"
KN23000 is 1/2"

If your coach has the push on air fittings, you better buy all new fittings. Once you remove the hose there is a very good chance they are going to leak. 

I believe the older coaches used nothing but the compression fittings were on the newer coaches they use nothing but push on.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: pneumatic check valves, pressure protection valves and aux compressor replumbing

Reply #5 –
Quote from: turbojack –
I am getting message that the file is corrupt.  I downloaded a second time and same message.

If you mean the parts manual, it comes up fine for me.  I let Steve know.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: pneumatic check valves, pressure protection valves and aux compressor replumbing

Reply #6 –
Michelle that parts manual will certainly prove useful and what an amazing document.  I assume that this manual was not typically delivered with the coaches to the customer.  Do you know who originally sourced this and how they got it?  I also assume that Foretravel does not hand these out upon request.  At any rate, thanks so much for sharing as this document appears to be at least 95% accurate for my 2002 as well.  Thank you!
George Mann
2002 U320 #5934
2017 Rubicon
2013 BMW GS
Waterford MI

Re: pneumatic check valves, pressure protection valves and aux compressor replumbing

Reply #7 –
Quote from: Geodmann –
Michelle that parts manual will certainly prove useful and what an amazing document.  I assume that this manual was not typically delivered with the coaches to the customer.  Do you know who originally sourced this and how they got it?  I also assume that Foretravel does not hand these out upon request.

Foretravel absolutely won't hand these out - we asked about getting one for our 2000 last week and were told flat out "no".  I have no idea how the procurers were able to get the three we have in the Media section.  Would love to have others. 
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: pneumatic check valves, pressure protection valves and aux compressor replumbing

Reply #8 –
I have the 2001 U270/U295 Parts Manual if anyone would like it.
I tried to insert it here, but it says the file is too big.
Mark & Bev
2001 U295 36' Slide
Cummins ISC 8.3 350HP
Build #5802
Jeep Wrangler Toad

Re: pneumatic check valves, pressure protection valves and aux compressor replumbing

Reply #9 –
I would love to get a copy of that.  My coach is 2002 but between the 2001 and 2003 parts manuals i would think most everything would be covered.
George Mann
2002 U320 #5934
2017 Rubicon
2013 BMW GS
Waterford MI

Re: pneumatic check valves, pressure protection valves and aux compressor replumbing

Reply #10 –
Quote from: MarkC –
I have the 2001 U270/U295 Parts Manual if anyone would like it.
I tried to insert it here, but it says the file is too big.

Is it different from the 2001 U270 parts manual in the Files library?

The selected media item is not currently available.

Quote from: Geodmann –
I would love to get a copy of that.  My coach is 2002 but between the 2001 and 2003 parts manuals i would think most everything would be covered.

Your slide mechanism and air awning (if you have one) will be unique to 2002, but I don't think either are in the parts manuals.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320