20 yo heil package unit, NOT a heat pump, contactor is humming, not loud, but I thought the contactor was on it's last legs. It still works, but in checking I noticed it is a 2 pole 40a/24v. The oe replacement parts list shows a part number for a single pole, 35a, 24v. If I simply go by the originally installed part, I would use a 40a 2 pole part. Would there be harm in using a single pole 40a/24v part, because the parts list says ssingle pole? If using a single pole, does it matter what wires are hooked to the shunt vs the pole, since nothing works till both legs are energized?
Also, for an uncomplicated hvac with no accessories hooked into the system, why have a 2 pole contactor in the first place? are single pole/2 poles contactors sometimes interchangeable?
Also, for an uncomplicated hvac with no accessories hooked into the system, why have a 2 pole contactor in the first place? are single pole/2 poles contactors sometimes interchangeable?