Intercooler Pressure Valve

by Neil
(Wauconda, IL USA)

Rol-Air (Chinook) K28 pump intercooler

Rol-Air (Chinook) K28 pump intercooler

I have an older Rol-Air (Chinook) K28 pump and there is an adjustable pressure relief valve on the intercooler.

Unfortunately the set screw is loose and I don't know what pressure it is supposed to be set for.

The current K28 does not have this valve so it is not mentioned in the manual.

Rol-Air says they don't usually use a safety valve on the intercooler, but some of their OEM customers do.

They did not have a specification. I found a generic recommendation on the web for 75 PSI and the Rol-Air tech thought "Maybe 120 PSI".

Any ideas?

Apparently the idea is if the High Pressure side develops a problem, this will vent before doing more damage. So no valve is OK, as long as all is well.

Maybe I'll start at 75 PSI and see if it pops off at all, then raise it if it does (stopping at 120 to check for other problems)

Rol-Air is not actually the manufacturer of the pump, Chinook in Italy is, but I have yet to find any contact information as every search for a Chinook K28 takes me back to Rol-Air or another distributor, but not the manufacturer.

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Nov 12, 2016
by: Neil

OK, so I pulled it off, since I figured I would have to put it on my small compressor to test and set.

Once I got it off and clean, I saw a small "75" stamped into it.

I also found a small punch mark that was intended to lock the adjustment.

So my guess is they buy adjustable relief valves, adjust them and them lock them in place with a punch able them. Or maybe the valve company does it this way for odd setting relieve valves that don't need an ASTM certification.

So I dissembled it and cleaned it, the put it together at about 1/2 way in the adjustment range and attached it to the outlet of my regulator.
It started bleeding air at about 100 and tripped about 110.
I backed it down to where it starts leaking just past 75 PSI and trips around 85 PSI.

Reinstalled it and so far so good, but I have only taken the pump and tank to 150.

I need to fix a small leak in a fitting before I go all the way to 175 to see if it holds.

Nov 11, 2016
Intercooler Pressure Valve
by: Doug in

Ya gotta start somewhere...

unless you just plug it (I wouldn't).

Let us know what you wind up with please.


Nov 09, 2016
More info
by: Neil

I found a relief valve specifically labeled for intercooler use and it is 4.5 Bar (65PSI), so I might start there.

Nov 08, 2016
Chinook k28
by: Doug in

Sounds about right for a 160psi pump.

Personally, I'd stop upping it about 10-15 psi over whatever holds.

Let us know what you wind up with please?

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