Electric funace won’t come on, AC will
My wife happens to be at a cabin we own and called to report that while they had heat last night, tonight they do not. It seems that when she turns the Thermostat to Heat the LCD goes totally blank whereas usually you can press the buttons and see the display change as you adjust the temperature. But the furnace won’t come on now, and the LCD on the thermostat goes blank.
If she turns the thermostat to AC, the AC does come on and the LCD lights up accordingly to adjust the temp.
There are two circuit breakes on the furnace unit itself. She went down and checked, one of the two was in the off position. I don’t know if it was supposed to be off or not, I never paid attention to it. She flipped it on,however, and retested the thermostat and it was the same thing. Blank on heat and not blank when turned to AC. She adds that when turning the thermostat to heat the furnace doesn’t even come on, it’s not even blowing cool air.
Ideas?
Replies
Lots of questions need answers to even take WAG at that one.
At first blush, look for a blown fuse on the circuite board. It may be a automotive type fuse or a small buss type fuse, and will be on the board that the T-stat wires terminals are on. There may be more than one fuse, so look carefully.
Other information needed: Type of furnace i.e., gas,oil, electric, heat pump,..., age of unit, type of T-stat, number of transformer in the control circuite, etc.
Or just call a service tech., locally.
Dave
Hmmm, an interesting update......I had her try again this morning. Now the thermostat will display when set on Heat and Auto. It read 55 degrees. I told her to set it high to 70 to make it run for a while and to keep verifying the temp is rising on the t-stat. The ONLY thing she did different is she turned the t-stat to OFF last night and it stayed that way overnight. Maybe that had something to do with it? Or there is an internal switch, like a delayed relay in the furnace itself that needed time to reset itself?If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
Ah yes, just figured out what the problem most likely is. A JUNK T-STAT. It's an American Standard. From all I've heard, AS are HD junk specials and you get what you pay for. I've also heard this about Hunter brand as well. My cheapo T-stat is prob intermitently going out. I'm going down in 4 weeks myself, I'm replacing it with a Honeywell.If at first you don't succeed, try using a hammer next time...everything needs some extra persuasion from time to time. -ME
If this T-stat is programmable, see if it has a battery backup. Mine does and when the battery goes bad, it acts up, too. Also, check the terminals in the furnace for loose screws and broken/gnawed wires.Also, if a T'stat goes bad, it won't usually cause a breaker to pop. All the stat does is close contacts for a set amount of time or after receiving info from the main board.
"I cut this piece four times and it's still too short."
Edited 11/30/2005 9:47 am by highfigh
Sounds like a call to the furnace tech is in order. Maybe a short in the furnace's circuitry and a thermostat that's short protected? Either way unless you're pretty adept at this stuff I'd make the call...