10 Ton rooftop question

[boho]

I have no experience with rooftops, my best friend has a Snyder General 1990 10 Ton unit that the second compressor is not engaging. I assume the 2 compressors are staged. My question is what stages them? I haven't had a chance to study tthe wiring diagram, but thought someone out their can point me in the right direction. :cheers: I know it should be replaced but he doesn't have the $$$$$$

[skippedover]

Try again on the commercial side of things. Most homes don't have 10-ton rooftop units.

[Timmy414B]

thermostat. 1st stage usually has a 1 degree differential, 2nd stage is usually a couple degrees less than that.

[boho]

opps-----thanks