Sizing circuit for geothermal compressor

[lwc778]

Hello:
I am wiring a circuit for a new geothermal system (Waterfurnace Series 5 unit). I am in between the HVAC company and an electrician that I'm working with, both sides are telling me different information on what exactly I should be installing for the circuit breaker and disconnect switch.

The geothermal compressor tag says RLA = 27.1, LRA = 152.9, Max HACR breaker = 70, Min Circuit Amp = 39.7.

The distance is 86 ft from our breaker panel to the unit, so I was planning on running #4 copper to allow for voltage drop. Will installing a 60 amp breaker have any advantage over a 70 amp? I was guessing 70 amp would be a closer fit for the #4 copper cable but was told to go with a 60 amp breaker.

The second question is what rating for the disconnect switch. They make a 60 amp and then it jumps to a 100 amp. Since we are going with #4 copper (70 amp rated), should I go with a 100 amp switch, or does that depend on the breaker used?

Hopefully this is straightforward. I have also posted a pic of the label directly on the geothermal unit:

https://imgur.com/a/zLhNB2A

Thank you.

 

[Dennis Alwon]

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