Had two out of three units down last week for the same reason. All three units wired together. Unit one was OK but unit two cutout number two and number three.
What was the issue with yours? Mine was covered with dirt initially. I cleaned it and it worked for about a week and then tripped again. I went back and noticed some of the screws on the terminals were really loose. I tightened them on Tuesday and it's been working since. I'll keep you posted.
If you jumper R to Y at the board of the RTU. The compressor won't run, unless the blower contactor is in also.
First time you run into one, it throws you off.
Wish I had seen this post when I first started into commercial....
Got to a cooling only unit when I first started at a commercial shop. It was heating season still so I was taught jump R to W and voila. So then I went to jump out this cooling only unit going R to Y and nothing. Called my journeyman who was working on something in the building and showed me his 3 headed jumper. Put one to G and the unit sprang to life.
Now its a force of habit. Ive seen some older Yorks that have had their boards changed that need R G and Y jumped out too. The compressors on them will start. But they will frost up quick since the blower wont be running.
jump the 5 amp fuse? wont that short something out
It COULD cause something to release the "factory smoke," that's for sure. The guy before him had done it. Many of us use the "Li'l Popper" circuit breaker to replace the fuse UNTIL the high current draw is located and corrected.
[Avatar photo from a Florida training accident. Everyone walked away.] 2 Tim 3:16-17