Comment on Does it make sense that a fridge relay start winding would get only 20 volts from the thermostat?
Onomatopoeia@lemmy.cafe 3 days ago
Is there a step-down transformer anywhere? That relay isn’t big enough to have such a transformer or switching power supply (I don’t think).
It would be strange (to me) to build everything for 220, including the t-stat, but not the start winding. That would then require either a transformer or switching power supply for that one thing.
The thermostat should be easy enough to test - you know where the supply is, and which wires energize this relay. Test voltage at the relay when the thermostat closes.
If something is dropping 220 to 20v, surely it’s got to be heating up?
diyrebel@lemmy.dbzer0.com 3 days ago
I doubt it… unless that’s something we would expect to find in a fridge? I see no big coils. There are also no fans on this fridge. No start capacitor either. The YT videos I saw do not correspond well with this. There is no freezer→fridge damper either. There are coils in both.
I cannot easily remove the thermostat… hard-wired in, otherwise I would try putting it in a working freezer then check that it closes. But OTOH that test is perhaps not useful since the problem is not continuous running. The problem is not running at all.
I can’t access that wiringwork page, but I would expect current and voltage to both be zero when the thermostat is happy. In any case, I appreciate the feedback.
Onomatopoeia@lemmy.cafe 3 days ago
I wouldn’t expect a transformer anywhere, I was just shooting in the dark. That would make no sense to me, but I’ve seen crazy stuff in appliances.
A better test may be to forcibly energize the relay so it closes. If it closes and the motor starts, the problem is in the thermostat. If it closes but the motor doesn’t start, the relay is the problem.
diyrebel@lemmy.dbzer0.com 2 days ago
By this, I assume you mean to hotwire the relay. I was actually planning on that. But then when I saw that the thermostat was sending 20V to what seems to be ultimately the start winding pin, it triggered me to first start this thread.
I am confused because I would expect there to just be two wires going to the relay. I believe it’s the relay’s job to break that into 3 pins. The relay has a connection that clearly goes to the common pin, which is the load. There is also a connection marked “N” for neutral, which goes to the run pin. The voltage across those two pins (coming from the thermostat) is 230v. So far, that’s all expected.
But then there is a 3rd wire from the thermostat going to (what I think is) a line that ultimately leads to the start pin. There is 20V across that and the load. So how do I hotwire that? I would obviously connect the load to and the neutral wires to their respective inputs, but I don’t know if it’s safe to jump the neutral to that 3rd input (which I think is the start pin). There is like ~54 ohms between the start and run inputs on the PTC relay.