ive been working on and off(between my competitors) on a J4sff-40b..
brand new out of the box i replaced the controller under warranty..a couple years later im called and see someone replaced a compressor but now the system is hot (its a freezer) evap fans were running and nothing else..
called cold/tech they suggested i replace the controller again, and i did.
went to 0 and i bailed..next day customer says its hot..i come back call cold/tech we go over the digital setting, everything is good..i looked at it yesterday and its still good..tonight i get a call...warm 40*...MOnday ill go back in the a.m..
any of you guys work on these things??
If you don't already have it, here's the manual for that:
I've only run across one Coldtech reach-in freezer like this one. It was serious iced up because it had a bad coil temp sensor so it would immediately terminate defrost.
For your situation, hopefully they'll leave it running until you get there so you may have a better chance of observing what it's doing...or not doing.
If you find the box warm, fans on but compressor off, check the #1 output from the controller to see if it's calling for the compressor. If the displayed box temp is above setpoint it should be calling. If not your controller is bad...again.
If it's iced up, check the evap coil temp sensor. If it's bad, disconnect it and set the controller for time terminated defrost until you can get a new sensor.
thanks ice...i have a feeling its the controller....when i called their service guy it was like he was scratching his head...im going up tommorow..
And why are the fans running with a hot evaporator?
Originally Posted by primmers
That's just the way they do it. No fan delay on coil temp....just on with the compressor.
Originally Posted by pecmsg
Check out the sequence of operation. If you can make your way through the very bad English translation, it says that on startup, after a 1 minute delay the evap fans and the compressor start.
I just read it. You’re correct it is a tough read. I feel sorry for the new kids.