Heat Pump Contactor Troubleshooting

[TheSuperClaude]

How do you know the Ohms range is suppose to be 10 - 20 ohms? Is that a general rule of thumb for a 120/24 volts contactor?

[loudogg50000]

I think with ohms law if it was reading 1.4 ohms at 24 volts it would be drawing 17 amps and at 10 ohms it would draw 2.4 amps.Most fuses blow at 3 or 5 amps.so that makes sense.

Great video and rule of thumb thanks

[talyn875]

@loudogg50000 great point- absolutely right.

[mayhew23451]

so just measure resistance from 120 to 24 volt side if its in 10 ohm range its good?

[talyn875]

@mayhew23451 measure from either side of the 24 volt coil. should be at least 10 ohms up to 20.

[MrGarcon98]

in watching this video i noticed you did not take the wires off the contactor to take a reading? not worried about back feed? nice job though

[mackbrower]

Thanks for the video

[yrtuag]

How do you know the coil resistance value?

[talyn875]

@yrtuag The value is measured in ohms. It is measured on the terminals on either side of the above contactor. These are the terminals where you see the blue and yellow wires. The value on a working contactor should be above 10 and less than 20. Less than 10 and it may short out the low voltage circuit.

[talyn875]

@yrtuag Other contactors may be different. Honeywell contactors used to have both sets of terminals on the same side.

[yrtuag]

@talyn875 Yes, I have installed hundreds of them over the years. And have troubleshooted many shorts. I was wondering where you came up with those numbers? Thanks.

[talyn875]

@yrtuag a wiser tech than me once told me that years ago. seems to me most of the bad ones read about 1 t0 5 ohms most of the time.

[yrtuag]

@talyn875 Thank you for the info and to that wise tech.

[ken6675]

great vid talyn, ac seasons here ready or not

Ken g

[talyn875]

@ken6675 yea buddy- let the long days begin.