IR P250/WCU question

[will_gurt]

I am at a loss for an answer for this commpressor. I can get it running. It builds air to to 130 PSI. The trouble it has, is when the unit returns to idle the unit shuts down. It is like the idle is set too low. One other thing is it seems the fuel shut off selenoid loses power.

Could there be a problem in a pressure relief circut? Sorry for being vauge but it is a little late in the day for me.

[Goose]

Sounds like the diaphram in the unloader valve could have a hole in it. When the machine starts up the unloader is open and as the pressure builds up and the engine starts to idle down the unloader valve starts to close to stop airflow into the screw and loading it down and dieing. If the diaphram has a hole in it, the unloader cant close and snuffs of the engine due to the load and the engine being at idle speed.

[will_gurt]

Sounds like the diaphram in the unloader valve could have a hole in it. When the machine starts up the unloader is open and as the pressure builds up and the engine starts to idle down the unloader valve starts to close to stop airflow into the screw and loading it down and dieing. If the diaphram has a hole in it, the unloader cant close and snuffs of the engine due to the load and the engine being at idle speed.

Thank for the reply. This would make since then. I have had some wrench time on other types of heavy equipment just not much if any on commpressors. Where would this "unloader" valve be located at roughly?

I.E. directly on the screw, on the lines leading to the throttle cylinder, ETC.

[will_gurt]

Finishing update. Checking every sensor, we found that the sensor on the front of the compressor (Compressor TEMP? ) is non functioning. This was the cause of the unit firing up and shutting right down. Confirmed the unloader valve is good and that the throttle cylinder was way out of adjustment for it to idle.

Again, goose, thanks for your help.

[will_gurt]

Finishing update. Checking every sensor, we found that the sensor on the front of the compressor (Compressor TEMP? ) is non functioning. This was the cause of the unit firing up and shutting right down. Confirmed the unloader valve is good and that the throttle cylinder was way out of adjustment for it to idle.

Again, goose, thanks for your help.

Checking in again. On further examination, The shut off selinoid was "backyard" wired into the altenator wiring. This was part of the cause for shutdown when returning to idle. Seems alternatorsdon't make enough draw to hold in the run position.