If the old unit failed because of the external load, it will likely happen again.
Resurrecting an old thread here, but I appear to have the same problem. The controller cools to the set point but the cool relay never shuts off. If you are saying the external load may have caused this, what do I need to change to avoid it overloading a new unit? It is powering a 7 cubic chest freezer and that is all. My unit is wired exactly as the picture above. Do I need a different controller? Could a power surge during a storm cause this? If so, how would I change the wiring to protect against that in the future?
Thanks!
A 7 cu ft chest freezer shouldn't pull more than a couple amps, except for a brief moment during startup.
Does the relay not shut off or are the contacts fused together? The latter could happen with an overload at some point or just a fluke relay. If you're handy with electronics you can replace the relay. A power surge can damage the electronics in the controller, but it would typically not work at all after that.
I will need to go pull some things apart and take a closer look to see if anything is fused together. Simple observation shows that the controller shuts off the cooling mode (no red dot next to cooling) but the cold side of the outlet still has power. Then, because the keezer is still cooling, the controller eventually kicks on the heating side (red dot next to heat) yet the cold side of the outlet still has power. The first time this happened was during a recent snowstorm, so that's what has me thinking power surge. It also resulted in 4 frozen kegs.
I suppose I will start by trying to replace the duplex outlet so I don't have to rip apart the inside of my keezer.
Sounds like the cold relay's contacts are fused.
If you have a multi meter you can test for permanent continuity of the cold relay. It would always be ON if the contacts are fused, even if the STC is not powered. I'd check that first, after unplugging the unit from the mains.
How would a duplex outlet fail, apart from hitting it with a hammer? Besides, the STC powers it. Should we assume the STC/freezer worked fine before, and it's not bad wiring?
Sounds like the cold relay's contacts are fused.
If you have a multi meter you can test for permanent continuity of the cold relay. It would always be ON if the contacts are fused, even if the STC is not powered. I'd check that first, after unplugging the unit from the mains.
How would a duplex outlet fail, apart from hitting it with a hammer? Besides, the STC powers it. Should we assume the STC/freezer worked fine before, and it's not bad wiring?
So, I readily admit that I have difficulty wrapping my head around most things related to electricity. I have used the multi-meter I have, which is pretty old and rarely used (there is no audible tone to indicate continuity). From what I can tell the cold relay does not appear to be fused. I tested the probe connectors on the unit and my meter reading changed, so I assume that indicates continuity. That did no happen when testing either the cold or hot relay.
So, either I'm more clueless than I thought and I'm using my multi-meter incorrectly, or there is something else wrong. Is there something within the controller that could cause the unit to turn on both relays when in heating mode?
I've bought a new unit and am close to just re-wiring everything. Just seems easier than me bumbling around like a moron.
So, I readily admit that I have difficulty wrapping my head around most things related to electricity. I have used the multi-meter I have, which is pretty old and rarely used (there is no audible tone to indicate continuity). From what I can tell the cold relay does not appear to be fused. I tested the probe connectors on the unit and my meter reading changed, so I assume that indicates continuity. That did no happen when testing either the cold or hot relay.
So, either I'm more clueless than I thought and I'm using my multi-meter incorrectly, or there is something else wrong. Is there something within the controller that could cause the unit to turn on both relays when in heating mode?
I've bought a new unit and am close to just re-wiring everything. Just seems easier than me bumbling around like a moron.
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