My wife thinks I'm spending too much time in the basement battling the behemoth we call our "furnace". I, though, am influenced by my media - and my media of late has been murder mysteries (e.g., Rex Stout's Nero Wolfe) and A Christmas Story (with Ralphie and Randy and the Red Rider BB Gun). And the father figure (The Old Man) in the story wages epic wars with his coal furnace. My little skirmishes do not compare. Yet.
To begin with, I've been in the process of expanding the suspect list as much as is viable. This isn't under American law - every aspect of this furnace is guilty until proven innocent. And here's what I've got:
1. Early on, I made an error or two - assumptions. I spent last Saturday cleaning out the reusable filters (ionizer-type). There're four of them. They were disgusting (that's a confession). I also pulled the Inducer motor, all the drainage hoses, and the condensation cell panel and cleaned out all the holes in this. I had gotten a chunk of wax to put in there that was supposed to be good look in keeping away the algea (sold by a furnace company for that purpose). I applied oil to surfaces, rtv, and hooked it all up again. Ran Beautifully!
But let's back up. A few weeks back, the furnace (maybe 12 years old?) started to not be able to raise the temp in the house any more than a degree or two without stopping, taking a break, then trying again. I knew something was wrong then. It was only a matter of time...
So, let's catch up. We had our furnace back. For a day. Then it started to go downhill fast. I was too busy to dig into it for a day or two and by the time I got back to it, I found a bloody mess. A thick, white, oily goo had clogged up the drain lines out of the condensate cell. Was it the wax? or had something else gone down? Only one way to find out. Inducer housing off again, the wax was the obvious issue - it had bloated with the water and was issuing goo left and right. I pulled it out with a pick, put a drain hose onto the condensate cell that emptied into a bucket, and proceeded to flush out the condensate cell. I also had the good luck to be able to flush out all the lines again and get all that goo out. Back together (oiled, and rtv) and it worked marginally better. Not good. Rather than not running at all - it ran for a few minutes then shut off. Then, the fun began.
And the most recent portion of the history is that yesterday I began the real digging. The troubleshooting guide says to check the voltage running between TP6 and C (test point six, and terminal C). If it's not 24v, somethings wrong. It was 23.5. I figured that was close enough. But the next time I attempted to find TP6 - it had moved. Nowhere to be seen - just a bunch of jumper wires and resistors. I'm still searching. (I found it, really, not so hard, but when you have it in your mind to find TP1 and it's not the test point you remember, and you ought to be looking for TP6 - it makes things difficult)
I set that aside for the time and started looking into the burner enclosure / combustion box. I took off the panel - nervously - not sure what I'd find, or if I'd be struck dead. Nothing but a box with a few horn shaped burners, an ignitor, a flame sensor (FS) and a bunch of dust and dead bugs. Vaccuum in hand I did my best. I even ran the furnace with this panel open - it didn't like it - too much air, apparently. But I did get another clue to chase down - the air intake looked inhabited. I popped that open to find a layer of detritus. Again - vaccuum ho! No rodent sign though. But my mind is clicking.
Another observation - when I had the drain line running into a bucket, I found that there was a bit of suction on that line from the inducer motor. I think it would do better as a closed system. So I did hook up the original line that drains into the drain trap. No improvement though.
And lastly, I do hear the pressure switch flip when the system shuts down. What does this indicate? (it does this, apparently, when the inducer quits sucking air, which happened in sync with the flames shutting off, though the blower motor remained on for a few minutes)
At this point - I have a few ideas: 1. blockage in the intake line. 2. blockage in the exhaust line. 3. cracked solder on the control board. 4. dying inducer motor. 5. Clogged heat exchanger. 6. Something to do with the pressure. (and one other item on the trouble-shooting list - a satisfied or malfunctioning thermostat)
Here are my links:
My own photos (of my own furnace)
Carrier actually publishes their maintenance manuals. Mine's a 58SXC080
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