Hello. I was hoping someone might be able to point me in the right direction. I have. Carrier high efficiency furnace model 58MVB. It has been in service about 13 years. There is a 12- 2 electrical run to a switch next to the furnace with an 8 amp type S fuse. Last week the furnace stopped working and the duse was blown. I replaced the fuse and the furnace appeared to work for a couple of days. Christmas eve I got cold again and the fuse was blown. Everything was closed so I could not get another fuse. Because the fuse blew, there was no code. So i bypassed the fuse and direct wired the furnace. The furnace ran for a few minutes then stopped. Now I have code 34. The ignitor came on fine and it fires up ok but the flames sputtered. After doing some research, it though it might be the heat sensor. I pulled it and cleaned it. Then tried firing it up again. It worked for several minutes and the flames looked good. But after a few minutes it stopped again. This time with code 33. I checked the filter and air vents for obstructions. I did notice that in my several attempts that the blower did not always fire up. I thought it might be the capacitor so i replaced it hoping for a simple inexpensive fix. When I fired it up it worked fir a couple of minutes. Alas, no joy as it stops after 2 minutes. Now when I try to fire up the furnace and get code 12 and there is a humming. The blower is not running. Then the code goes to solid red and the furnace lights.the flames look healthy. It does not appear as though the blower fires up and i get code 33 when it shuts down. The flame rollout switch is not getting tripped. There is a small amount of airflow at a nearby vent with heat in the 2 minutes it is running. It seems to me that everything is pointing to a faulty blower. How do i test it? Are there any suggestions on diagnosing this? Is this something that can be easily fixed? I'm trying to avoid an expensive service call as this pandemic has my finances is chaos.

I have reason to suspect that the gas valve in my 25-year old Trane furnace may be going South. I've never had any trouble with the furnace until this year when on two occasions the heat wouldn't come on before eventually starting to work again on its own. The first time was after the furnace sat there all summer and the second time was after it sat idle for about three weeks. In both instances once it got going it kept working cycle after cycle. Our next door neighbors have the same Trane furnace, as both our houses were built at the same time by the same builder. I just found out they've been having a similar problem -- their furnace stopped working for a while and started working again. Finally it quit again, apparently for good, and their H&C guy says it's the gas valve. The original White Rodgers single stage valve is no longer made, and he quoted them $1,000 to retrofit a new replacement. They decided to opt for a whole new furnace for $2,000. Since the symptoms seem similar I'm guessing I'll be facing the same dilemma shortly. I see that original W-R valve does pop up on Ebay every so often in the $50(used)-$125(new) range. I'm wondering if it'd be wise to cough up $100 bucks or so for an old stock or used valve to have on hand as insurance, or would that just be throwing good money after bad? If it makes any difference I haven't really researched it enough to know whether I would be able to handle replacing the valve myself, but if that day comes and it's beyond me then I'm reasonably sure my H&C guy would install a customer-supplied part. Any opinions appreciated!