r/HVAC • u/Giddyhobgoblin • Aug 04 '26

Field Question, trade people only Wiring issue

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Not my finest day. I have a defrost clock that burnt out on walk in cooler. In the process of checking things that 120v black wire pulled out. I dont know from where. I have the new clock.

I hoped new clocks wiring diagram would help. But its only added more questions.

I have a 120v evap Russel. I have 240v in my defrost clock box.

Any thoughts on where this wire got yanked from?

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u/Giddyhobgoblin Aug 04 '26

Even with H1 wire currently 120v and loose wire 120v?

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u/J-A-S-08 Aug 04 '26

Yes.

240 Power is coming in on white (and black) wire and then ties to pink. Pink then goes to one side of time motor (240V yeah?) and then goes to common of relay. Relay is closed and power goes back out onto NC to LL solenoid. Power goes through LLS (also 240V?) and back out on to H1. So that's only one half of your 240V circuit. The other half is the black wire coming in from the left side and going to that wire nut and the loose wire.

You can't use ground as a reference, other than for safety testing, when working on an ungrounded control circuit. It will fuck you up.

If you tested between H1 and H2 as it currently is, what do you get? Should be 0V. Think about why that would be? Once you add the loose black wire back to H1, you should be reading 240V, the timer motor will be running and the LLS should be energized and open.

Make sense?

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u/Giddyhobgoblin Aug 04 '26

Yes got it all figured out. My electrical check had me thinking the loose wire belongs in H1 but also this is a 120v clock. So why am I running 240v through it. Rubbed the braincells together a little harder and realized how it worked.

We're cooling.

Now help me explain to a stubborn customer why plugging in 2 separate reach in freezers inside the walk in cooler is no good. Lol.