AB cold machine, new install, wierd cycle times...

[pressuredrop]

Ive just completed the install of brand new equipment, and fired up the system.

Meduim vertical bin evaporator and cu-100 compressor

It works great but the cycle times seem odd to me...

It runs for 4 aminutes and shuts off for 2, analog thermostat is on the coldest setting as it is still cooling the box initially....

I would expect it to run for hours till the box is cold cold...

No error codes on the flashing led. 10awg wire for power

The thermostat sensor is attached so the metal is touching evaporator and the rubber is on the clamp side... is this right? Thoughts in general?

[pressuredrop]

I can turn the compressor instantly off by raising the thermostat, but when i turn it back down it takes a few minutes to kick back on....

[pressuredrop]

Well now i get the error lights, 3 for short cycling, solution: wait, try again.... well this is frustrating

[Richard Kollmann]

Originally Posted by pressuredrop

I can turn the compressor instantly off by raising the thermostat, but when i turn it back down it takes a few minutes to kick back on....

On the CU100 thermostat temp sense tube only 5 inches of tube is to be in contact where it is to be clamped on evaporator. More than 5 inches or sense tube contacting cold refrigerant line or other cold areas of evaporator will cause the short cycling you describe.

[pressuredrop]

Thanks rich! I spoke with dometic tech support and they seem to think the thermostat is no good. I have bypassed it and it runs great for hours, the evaporator gets frosty, the compressor barely gets hot. The compressor is so quiet and remarkably little vibration its hard to tell if its running over the fan noise... this is normal?

[onestepcsy37]

probably not your problem but...
i also installed a new ab same as yours, awhile back. turned it on and went home. figured the next day i would have a cold box.
i came back the next morining to a warm box and a cycling compressor. would try to start, then stop. a few minutes later it would try to start again.
i called ab and they told me they already knew the problem.
when the compressor needs to be started the controller sends it a jolt of higher voltage to get the motor moving, then cycles back to the normal running voltage. but the summer i installed it was so hot that the jolt they had programmed in wasn't enough. they sent me a new controller with a higher jolt voltage and all was well. never had a problem of any kind ever again.

[Library70]

I put in a similar system about three months ago and had the same cycling problem. Tech support said that the analog thermostats are problematic. I replaced it with an Inkbird digital that I purchased on Amazon for $15. It works great and has a continuous digital temp display- no more opening the door to check a thermometer!