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.

Comments for Unloader issue with T-30 Model 242-5C

Click here to add your own comments

Feb 22, 2016
by: Doug in s.d.ca

Glad to hear it's working.

Please let us know how it goes...

Feb 22, 2016
IR T-30
by: Marion

I replaced the shim under the output finger valve on the output head. Compressor is working now. Interesting to see how long it lasts.

Feb 21, 2016
by: Doug in s.d.ca

"After all this, next day we checked the 325psi safety unloader at the inlet to receiver, it was inoperable at this time."

Can you tell why it's inop?

Feb 21, 2016
by: Marion

We had problems with the compressor magnetic starter during Christmas Chaos. Amperage on high side was about 4.5 Amps higher than normal when the motor started. Decided it was time for a visual to see what might be messed up.

All three of the safety unloaders were operable. Obtained new gasket and finger valves kit. Cleaned the heads, replaced all the finger valves, new pressure switch with unloader. We removed the safety unloader from below the pressure switch, connected copper tubing to unloader on pressure switch. Compressor operated correctly for about three or four days. Began the overload again. Removed that fitting replaced original. Removed the original check valve at the inlet to receiver, found to be inoperable, replaced with a check valve unloader, connected to unloader on pressure switch. Did not run properly. That is when we found information as to the check valve unloader not being correct for this compressor. Installed new check valve unloader. This is when the compressor pumped to 60psi, safety unloaders released pressure intermittently as expected, we shut down the compressor.

After all this, next day we checked the 325psi safety unloader at the inlet to receiver, it was inoperable at this time. Ordered new unloader, should have Monday February 22.

Trying most anything at this point.

Feb 20, 2016
by: Doug in s.d.ca

"Compressor pumps to 60psi, safety unloaders release pulsing air."

All the PRV? (PRV=pressure relief valve=unloader)

60 is about what the first stage puts out, so sounds like the second stage is inop, either blocked intake or output.

I think this one has an unloader built in at the other side from the sheave, explaining why there was no port on the check you replaced.

How'd you get started on this? Was it actually in service, or ?

Click here to add your own comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Ingersoll Rand T-30 Air Compressor Issues.