Brian (and alll other contributors to this thread),
I’ve been in this home since 1994, and it was built in 1936. The serial on the furnace starts with a “72”, so I assume it’s from that vintage.
In 1998 the fan was making a horrendous noise at the start of the new heating season that struck me as an off balance type of situation so I looked into it. I found clumps of dust in the fan cage, around the bearings and in the motor case (open drip proof case rather than totally enclosed fan cooled). I removed entire the blower assembly (on this furnace it’s just 6 screws, disconnect wires to motor and slide out of the box) and totally cleaned it up. I made a quick inspection of the unit downstream of the blower and it was quite dusty. Not an area I am familiar with so I called in a pro to make sure it was done right. (He was the first to tell me that the entire furnace was in great shape for it’s age.) He cleaned the entire duct system for us, and changed the controller settings so I could squeeze every degree out of the gas that I could. I figured he knew better than I since he was a pro. Harrumph! He turned out to be a total moron that ended up hacking my ducting system. Maybe that should have been an indicator to me.
Since then, I have cleaned the blower assembly as I did the first time and have the ducts cleaned every 2 years. By a different contractor no doubt!
I did not start adjusting the combination fan controller until the short cycling started this year. In fact, the last setting I tried has stopped the short cycle. It’s now at 110* on, 70* off. The indicator wheel still does that “hold-then-jump” routine around 80-85*, but the short cycling has stopped.
Oh yeah, we have not noticed any inconvenience in the air delivery temps since this is the most cold blooded home I have EVER lived in, and the floor stays colder than the rest of the room. Since the registers blow the air across the floor, it always feels warmer than what’s there already. Yeah I know, long past time to move! Doggone economy.
I’m setting $$ aside for the service call to have a pro come in, and I’m going to insist NACHI cert this time, for a full inspection and switch replacement if warranted. I just hope the cert means something (no dorks or sheisters!) and that I still have some time on the life of the unit. When it works normally, you only hear the gas solenoid click on and then the fan motor hammer on.
Once this unit demands replacement I plan on relpacing with entire HVAC unit.
Oh! There was a question on my duct system further up this thread so:
The intake used to be a panned floor joist cavity that ran from the edge of the foundation to what I assume may have been a coal fired furnace. In fact there are still holes in the wood flooring in that cavity at the outer wall. Good Call! I suspect once this Bard unit was installed, the intake and heating ducting was changed to accomodate the learnings over the preceeding 36 years or so. That joist cavity is now 3 feet away from the furnace and no longer connects to it. Each heating duct has an adjustable flapper in it to control the delivered air flow. I keep them all open, but have the ducts that dump into the living room with the thermostat closed slightly to ensure other rooms heat up before the thermostat sees it’s set temp. I would estimate these 2 duct flappers to be about 15* from full open.
Thank you again to all of the fine gentlemen that have contributed to this thread. I have learned from you.
Best regards to you all,