Hi, I live in near Nashville, Tenn. I have a Goodman HVAC unit model PG036100-1B REV E (gas furnace and A/C unit) over 20 years old. It started to make a very loud grinding noise when the furnace came on, so I had it inspected by a local HVAC repair company, and the tech said the inducer motor is failing (a broken fan blade caused too much strain on the motor bearing or some such). He also said there is a small crack in the back of the heat exchanger on the vertical seam. He said if the crack were anywhere but in the back, I should replace it immediately because these older units leak carbon monoxide(!! ) when the heat exchangers crack.

Here are my questions:

1) Is it OK to just replace the inducer motor assembly and wait on replacing the heat exchanger, or should I replace both parts/assemblies, especially because of the carbon monoxide issue?

2) He quoted $650 parts and labor to replace the inducer motor assembly, plus an additional $1,300 parts and labor to replace the heat exchanger. Is that a lot?

3) If it's going to cost me upward of $2,000 to replace these parts, would I be better off biting the bullet and replacing the entire unit because the newer units don't have the carbon monoxide issues and also because of the tax credit?

4) He stated that installing a new furnace/AC unit would cost at least $6,000. Is that true?

5) Were these older units built better than the new units, such that it would be better to keep replacing parts? This one has lasted almost 20 years. Although, since it's already that old, am I better off replacing the whole unit, mostly because of the carbon monoxide issue and also because all the other parts will probably start failing due to age anyway?

6) From everything I've read online, the newer units only last around 8 to 10 years? Is that true? If so, should I buy a service contract on a new unit (if such a thing exists)?

7) If it's better to replace it with a new unit, what particular brands and units are the most efficient, reliable, AND economical? I want to stay with gas heat. I despise heat pumps.

Thank you!

1. The crack is a MAJOR health hazzard. If you replace, you need to replace all. I'm surprised he didn't lock the unit out.

2. Probably not horrible. Check the heat exchanger warranty, Sometimes it's lifetime.

3. At 20 years old, replacement is worth considering. Cracked heat exchangers are common to all furnaces, new and old. Those that use outside cumbustion air don't really have the CO problem, but should be replaced if cracked.
If your not comforatable with your present system, or even if your are pay someone to do a manual D (Duct) and Manual J (heat load) calculations. Increase in efficiency and fuel costs ought to be considered. Dual fuel (gas combined with heat pump) ought to be considered as well. Your dealer ought to able to tell you what may be cheaper and whether a HP should even be considered.

4. Get at least 3 quotes. $4K isn't unreasonalbe. Mine cost about 7K.

5. Possibly built better. The three major components are inducer, blower and heat exchanger. Replacing the induder with an Evergreen motor may increase efficiency. If the furnace does not use an ECM motor (30% energy savings) then it might push things more for replacement. The heat exchanger and the furnace board availabilty are the parts to worry about. Make sure the heat exchanger is still available- might make your decision really easy.

6. Probably not. Just make sure you get a decent warranty. Do we know how long the are going to last - nope. Your problems, I believe, are related. The blower housing caused the inducer to slow down, which caused the heat exchanger to get hotter than normal and the heat exchanger cracked.
If you want to invest in an insurance policy, get a wired in surge suppressor. A whole house version is best and place an RFI filter at the furnace (about $100).

6. The unit is as good as the installer. 96% efficient furnaces are possible. If you have a water heater, these funnaces would reguire to be direct vented and the water heater would need a chimney liner (flex metal tube). This contributes to the cost if your present heater doesn; have it.

Considering your in Florida, a high SEER rating for the AC is probably what your after more so than a 96% efficient furnace. Only the higher ratings qualify for the federal tax credit. They must be a certain combination and professionally installed. Your line set has to be new or flushed to accommodate R410A which replaced R22. The outside unit tends to be larger. The direct concentric vent kit looks nicer tha two PVC tubes out of the wall.
Brands - can't say.

Make sure you determine any extras you need in your system. UV lights if people in your family are subject to colds/flu. Large pleated filters. Electrostatic filters with a large pleated filter combo (Aprilaire 5000, for instance). Charcoal filters?

Multi-speed blowers are quieter. A thermostat that's capable of dehumidifying (runs AC at a slower fan speed).
2-stage gas.

Multi-speed/stage AC

And for much wierder installs an HRV or ERV. Heat recovery ventilator or Energy recovery ventillator. A high priced addition to a furnace that allows outside air to be used for ventillation/cooling.

And for even wierder installs where a HP/AC can be mounted before the heat exchanger, such that you can cool and re-heat the air for the ultimate comfort. This is how commercial HVAC systems can operate.

yep, gave you lots of options. Use lifestyle, energy costs, medical conditions, outdoor air quality, climate to help determine your options.

If you use the AC 100% of the time, then consider the highest SEER with a variable speed blower.

If outdoor conditions are largely favorable for cooling then consider an ERV/HRV. Consider it also if your house is tight and would like better ventilation.

UV lights have to be replaced yearly, but they remove mold and live viruses in the heating system.

Large pleated filters are the way to go.

If you want to filter smaller particles or have server allergies, then consider the electrostatic addition.

Say your severely allergic to Ragweed and in the fall the temperatures outside are very favorable for cooling. This would be a great reason to use an ERV/HRV.

Comments?

PS: Thanks for clearly stating and numbering the issues. Much appriciated.

KISS provided an excellent response to this question about a Goodman gas pkg (Model PGB036100-1A) inducer motor. Here's a similar problem: My inducer motor does not come on, apparently stopping the sequence of events leading to ignition in heating mode. My first impulse is to replace the motor, but I observe that the power coming into the fuse box for the unit registers only about 56 volts on each side. What would account for this? Would this be insufficient to start the inducer?