I have a 1970's Carrier Heat Pump, possibly 1977. It's been a very good unit, but every couple of yrs have trouble with it and have to call a repair person. Repairman hates working on it and calls it a "dinasour." He says he has trouble diagnosing it because he has no reference to refer to. I REALLY need a manual. I can't really afford to have to buy a new unit. If you could supply me with a service manual for this unit, I would be forever in your debt! Thank you so much, Becky Jones