Ranco temp controller issue

[SanPancho]

so just noticed my ranco has been acting up. cant figure out what's going on with it.

its in cooling mode. set temp is 55. diff is 2. current temp is 59. no power to the cooler. when i plug the cooler in directly to power it runs. but the ranco isnt kicking it on for some reason.

extremely odd that this just happened out of no where. there are no other options i could see that might be off. super simple controller setting on these guys: c or f. set temp. differential.

not sure what else could be happening with it. think it just went bad? only had it about 3 years. doesnt get alot of abuse.

 

[day_trippr]

If the display indicates the Ranco has the relay closed (I think it's "S1" on the display) but the compressor isn't actually running there's a good chance the Ranco output relay has failed...

 

[SanPancho]

crap. Ok. Time to open it up and see for sure.

 

[day_trippr]

Pretty sure the relays used in the single and dual stage Ranco ETC units are rated at slightly below 10A @120VAC, which puts them in the same ballpark as most similar controllers (STC 1K/MH1210/WH7016/and a whole slew of Inkbird products). Like all relays the points can get baked over time and the resulting carbon will eventually result in a high-impedance path that can't sustain a compressor load.

If you feel this failure was premature consider using your ETC (or its replacement) to control a Big Honking Relay that switches the actually load...

Cheers!