Had a first today. Ran the furnace and it functioned fine. Turned off the service disconnect and pulled off the panels. Everything good. Replaced the panels and could not get it to start. I triple checked the breaker, service disconnect, thermostat and service door safety switch. All were in the proper position. Tried shutting the system down and allowing time to reset but nothing. I have a hunch that the door panel safety disconnect switch may have went bad as normally I hear a “click” when its activated but I had nothing. Just curious if that’s ever happened to anyone?
I had it happen once. But was a logic board that took a dive. Did you look for a light on the logic board?
How’d you handle it, with sellers, REA’s, etc.?
Unit failed during testing , as long as all the doors where tight that is . Did you ceck the high water switch ? and fan door switch .
Regardless you were the last to touch it so in the owners eyes you broke it pay up:p
As stated if there was a light on the control board means the safety door switch was made. If the light was burning and the unit did not fire I would look to see if the thermostat was still calling for heat as programmable stats will convert back to their previous setting. If the stat is still calling I would then kill all power to the furnace and give the control board one last chance to reset. If that does not work just reach for your wallet its gona git lighter;-)
I had that happen with an AC. I think it was a fuse in the unit that blew. Listing agent said I owed him $85, but he didn’t see a penny from me.
If ya blew a fuse it means you were playing off and on with the thermostat and not allowing the refrigerant to equalize in the system. Ya should have paid that poor Realtor:p
I don’t ever use the service switch, that is for service. Use the tstat or just open the door and the unit stops. Put the door back on or turn on the tstat again and it starts. Reduces the chances as you had today.
Thanks for all the great ideas and feedback. I called the listing agent and advised him of the condition and that the house would not have heat…getting colder here! House is vacant with seller out of town. Listing agent sent over HVAC technician this AM. My “hunch” was right. Found a defective door switch. Must have finally had enough after I opened the door.
Nothing I could have done to prevent this…besides not taking off the cover, which is unacceptable in my opinion. Always something…
Never open the door if the unit is running. Use the controls and wait.
I didn’t blow a fuse. The fuse blew. That’s what they are supposed to do.
The easiest way to check is by bypassing the switch. Just pull the two wires off of the terminals and short them out to each other. If the furnace runs, the switch is bad. If it doesn’t run, the problem is elsewhere.
Only if they exceed their rating:p
Some of these guys would electrocute themselves that switch is a 120 volt circuit;-)
That’s one way to weed the garden.