I have a CarrierMVP080--14 variable speed furnace, installed in 1995, but with only about 400/500 Hrs. of heating total. Heating will not come on. Dealer diagnosed main control panel and quoted $800/900 to replace. Obtained new Carrier panel and installed, but no change in operation. Furnace displays Code 42 on call for heating, indicating problem with inducer blower/motor. Found on call for heating if inducer motor is just turned slightly (not spun) it will start. I do not with to replace expensive motor if this is not the problem. Any suggestions? Please help, I am frusgtrated.

If the combustion venting and/or secondary heat exchanger are restricted, it can cause the unit to produce the same fault code, but neither will impede the ability of the inducer motor to start on its own. Check all pins and sockets of inducer motor and wiring harness to assure good electrical contact. Check the service label for a component test sequence and perform as instructed. I hate to say it, but what you describe sounds like a failing inducer motor (the built-in speed-control module, actually), and that will be one expensive assembly to replace.

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