info needed on IG grb-125 air compressor

[unclehuck]

Hello all,
newby here, this site looks great! I am looking for feedback on my Ingersol Rand grb 125 gyow rotary vane air compressor. It starts and runs up to 100 psi real well, but when it unloads there is no sound of air being released. it just throttles down as it should and then dies. I have gone thru the carb, I am looking for other causes.
any help?
greg

 

[NDT]

When the compressor unloads (throttles down), no air is released. The unloader valve closes at the compressor inlet. Check to see if the linkage is closing this completely, otherwise, with the engine throttle at idle, it will cause the situation you describe.

 

[unclehuck]

Is this part of the ul88 controller that is hooked to the carb linkage
or the ul89 volumetric air controller that sits on top of rotary vane ?
thanks for responding
Greg

 

[NDT]

The volumertric air controller is another term for unloader. Make sure this is closed at idle, so no load is placed on the engine.

 

[Hormidas]

Cause of pressure relief valve

Hello,
I recently purchased a 1957 era Ingersoll-Rand GRB 125 Gyro FLO compressor. The last time I used the compressor I was just about to start using my new sand blast tank when the engine died and what I believe was the pressure relief valve tripped. I have dumped the compressor oil and found significant (to me), sludge in the drain plug of the oil cooler. I would like to know if it is recommended to flush the oil cooler, and if so how?
Also if someone is familiar with the relief valve is there anything I need to do to it?