Person selling lennox 3.5 ton whisper heat 1992 furnace for 400.00 Replaced motor on blower 2 mon. ago w/new.A-coil and cover and some duct work included. Should we buy?
You are taking a chance that someting else may be bad or nearing breakdon.
A critical part of a forced hot air furnace is the heat exchanger. If ths develops a crack then you can get carbon monoxide into the house.
Another part that can give trouble is the pilot light or electronic ignition.
Finsally if something major does break, you have the cost of installing all over again when you buy a new furnace,
The good conscientious technician or serviceperson will carry extra oils and lubricants in case the new pump did not come with oil or the oil was accidentally spilled, so the service call can be completed without an extra visit.