Hello, the blower fan/motor assembly on this gas furnace has recently started making vibrating noises. It had never been exactly a quiet appliance but lately it's a bit louder. The blower wheel is covered with dust and also -- the axis of the wheel has got about 3/4" play or slack, meaning the wheel inside the metal enclosure can be shifted along the axis by that distance. This furnace is definitely in need of maintenance, so I wanted to see if it could be taken apart, at least the blower motor assembly.

Does anyone recognize the model of this furnace from the photos below? Would greatly appreciate any hint! Thank you and Best Wishes, h.

 

Model number should be in the burner compartment. The motor will be generic and can be replaced by any that meet the specs.
Why is there a do not operate tag on the front? When was that furnace last checked out? It very well could have a cracked heat exchanger.

 

Thanks! Hasn't been checked in a few years. I think that tag says something like: "Do not operate anything combustible or flammable near this appliance".

Got it: Model No.: 3204-80HD

 

I’d get it checked before spending any money on it. A furnace that age needs yearly maintenance.
Have the burners pulled, check the heat exchanger, clean the burners and blower. Check gas pressure. That sort of thing.

 

Thanks! Yes, I could clean the blower assembly above the filter. There's also a lot of debris, looking like rust, around and below the burners in the burner compartment. The flames aren't 100% blue, with a bit of orange.

All that extra vibration/noise disappears if I lean with my hands on the front top corners of the furnace with about 15 lbs. of force. Not sure what it means though, the furnace is loose on its base?

 

Then it's time again !!

That furnace is roughly 35 years old. Furnaces were not designed to last that long and based on the old Rheem's I've seen.... and the rust in yours..... it's time.

 

Your going to need more then just cleaning dust around the blower.
As I said before the burners should be pulled.
You have a high likelihood that there’s a crack in the heat exchanger. If there’s a crack, the furnace is dead and unusable.
If there’s not, then it can be fixed.
But a crack presents a carbon monoxide danger to the occupants of the home.

 

Thank you guys for the responses. Yes, it's probably time to replace it. Overall, the furnace has been fine, heats the house well. I guess when it is shut down for the season, in about a month, it would be a good time to consider replacement.

Meanwhile, I cleaned the blower of the dust and debris. As far as the burners go, can they in Rheem 3240-80HD be cleaned with a long brush without having to take it apart? Then the heat exchanger still needs to be checked. I've replaced the thermocouple in this unit five or six years ago. Would checking the heat exchanger or cleaning burners be comparable in time and effort? Any big crack in the heat exchanger, around the burners or above where the baffles are, I would probably see myself, but that's definitely not good enough. Do technicians rely only on CO/CO2 sensors when testing the heat exchangers?

UPD: It turns out there are only two burners and they aren't the long, flute-like ones. They only go about two inches deep inside the heat exchanger but they throw flames deeper inside as in the photo below. By the way, after superficial cleaning and tightening a couple of loose nuts holding covers this furnace is quieter than ever, no vibration and noise that were there yesterday.