Thermostat trips breaker...

[tkaz]

Hi all, need some help here.   I am assisting someone somewhat local with a newer coke cooler, but he's having some trouble with the thermostat tripping the breaker.  I think I am past my knowledge of the cooling system, so I thought someone might be able to help.

Here's what's going on:

1. If thermostat is turned all the way down and unit is plugged in it it runs. The compressor never cycles off though.

2. If thermostat is turned up then you plug it in it trips the breaker.

3. If thermostat is adjusted up after it is up and running like # 1 then it trips the breaker.

4. Yes the unit gets cold. I let it run for two hours and there was frost on thew inside lid.

The thermostat was replaced and is new, but it seems like it may have a short in the 'compressor off' stage (this is where my knowledge gets slim).  He's a good hour away, so I can't get my hands on it to troubleshoot, but I can talk him through it.

The machine is a model RPUC100, I've got some photos, but it was manufactured in 1999, much newer than I'm used to.

Any thoughts?

[johnieG]

Yes, You have miswired the compressor directly across the line voltage & you have also miswired the Thermostat across the line. 

so the compressor will never shut off, & the T-stat (when turned on/past 1) will short out the line & pop your circut breaker.  search for "compressor 101" & you should find a basic wiring diagram of a typical machines compressor deck & Thermostat


this is a series wired circut, so treat the thermostat like a light-switch & the compressor like the light-bulb.

[tkaz]

Thanks! That makes perfect sense, and I'm sure he'll be happy to know it's just a wiring issue.

I can't find the post on Compressor 101, but the way I see it is:

From the A/C line, one side goes to the compressor, the other to the thermostat.  The other end of the thermostat goes to the compressor?

[johnieG]

(From the line cord) the neutral goes straight through to the compressor common terminal. the hot/black first goes to the t-stat, then the hot/black leaves the t-stat & goes to the compressor start/run relay box

[tkaz]

Thanks for the help on this one, the guys machine is up and running now, and he's a real happy camper.

Once we got all the wiring back in order, the thermostat was still not turning off the compressor.  Eventually after a lot of head scratching, I figured the thermostat was shot from being miswired initially.  He went to pull it out of the machine to find a replacement...and one of the wires was off in the back!  Reconnected, it runs like a dream...its always something...