Unloader issue with T-30 Model 242-5C
by Marion Ferguson
(Beavercreek, OH USA)
T-30 Model 242-5C Serial # 604188 Approximately 1984, 5 HP electric 3 phase
Replaced check valve in receiver. Unfortunately not exactly as original. Original did not have provisions for copper tube to an unloader at the pressure switch or anywhere else. Three Safety unloaders. Input cylinder, pressure switch, and at receiver input. Receiver input unloader is 325 psi other two are 183psi. Unit came from factory with pressure switch set at 175psi
Re-plumbed all copper tube lines so we didn't need to use reverse flare fittings. Reduced pipe size to 1/2" NPT brass above check valve. 1/4" OD copper tube to unloader on new pressure switch.
Compressor pumps to 60psi, safety unloaders release pulsing air. Stopped the compressor so it wouldn't possibly blow a head gasket on output cylinder. Unloader on pressure switch does not release air since it hasn't reached shut off pressure of 175psi, I assume.
This is second check valve we have installed. Further information found on first check valve stated it would only work to 5 cfm. Do not know if we have a problem with second check valve or not. They were both Conrader valves. I have since ordered another check valve from ecompressedair.com that is supposed to be replacement for original. It is not configured as the original, has outlet for tubing going to pressure switch.
I read somewhere that some of these T-30's had an unloader inside the case of the compressor. Do you know if this could be true? I have not opened the case to see if there is any indication of same.
Original check valve was completely non functional.
I am ready to place about a pound of dynamite in the tank, set it out in the woods and detonate it. We have been screwing with this thing for a month. We have a manufacturing business that requires this compressor. Have replaced head gaskets and all electrics. If for no other reason than this unit's obvious age.
Please help if you can.