Strange Furnace Behavior (Forced Reposting)
I am posting this again because apparently they have moved everyone, some of us, or just my lame butt to this new thingamajiggy. Anyway, to try to repeat in a more concise nature: When the wife or I set the heating thermostat the natural gas furnace comes on, hot air comes out, but the unit cuts off before ever reaching the temperature we set. Wife first mentioned it a couple of days ago. The temperature is now 66ºF but has been set to 72ºF all morning and afternoon. The furnace and blower just cut off before reaching this target temp. The unit runs, but not long enough–short cycling? FYI: This is the first floor zone. Separate AC and gas furnace using common blower. Second floor zone equipment works fine. Our neighborhood had an ungodly lightning strike early Wednesday morning and a lot of utilities needed repair, plus a lot of consumer electronics in several homes sustained permanent damage. I am wondering if there is a sfety mechanism in the furnace that may have been damaged, or something more common. NOTE: If anyone replied to the original posting on the original software I never got to see them. I got a notification, but it led me to this [insert any favorite adjective] forum implementation.
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Don't you just love it
Don't you just love it here?
I was surprised to see you post over in the "old" side, it was the first I'd seen in a while.
Question: Does your stat have any connection to line voltage, or only the LV wiring back to the hVAC?
Now, the air handler is "at risk" from surges, since it is connected to the line. Hope that none of the fan or sensor circuitry took a hit. Not sure who I'd call that I'd also trust to test the unit--so, you proabably may be looking at a $$$ service call.
Wish i could offer better.
The stat has only LV connections. I thought that maybe it was a 'Hold' feature that had been engaged and tried like a dickens to get it deactivated. Finally did and still testing. Its now getting up to almost 69ºF.
>>FYI: This is the first floor zone. Separate AC and gas furnace using common blower. Second floor zone equipment works fine.
Are there really 2 separate furnaces?
Try switching the theremostats and see if the problem "switchs" as well.
Bob, that is a good suggestion. Yes, there are two separate AC and furnace zones for the two floors. The thermostats are slightly different models. They were identical, but 2-3 years ago the 1st floor unit failed and I replaced it with a more current White-Rodgers model that replaced the failed unit.
BTW, the current unit down stairs is a 1F80-361, which replaced a 1F80-51 (the 51 is still in use upstairs). When I replaced the 51 downstairs it was only like $45-50 (cheap). I do not mind trying that again, and if that doesn't work have a spare.
Finally gave up and replaced the thermostat. Working perfectly now. I thought the tripping the breakers and resetting the existing thermostat did the trick, but it continued to exhibit an inability to hold a temp.
Looking back, in December 2005 I had this same problem on the same zone. And guess what, before i noticed this inability to operate normally the neighbor's house across the street got hit by lightning (again).
I guess about every four years or so I can expect this to happen.
On December 9th of this year, the neighbor's hour took another direct hit, causing damage to it and several homes on the street--including mine. I guess the repeat performance should be expected the next time that house takes a hit.
Thermostats contain an "anticipator" of one sort or another (anything from a small heating coil to electronic logic) that is intended to prevent "overshoot". The newer electronic ones are supposedly "smart" in that they "learn" how the furnace/house behaves.
It may be that the power surge has upset the memory of this circuit. Try turning off the furnace circuit breaker for about 10 minutes to reset it. (Also remove any internal battery, if it has one, for that period of time.) (But check first to see if there's a "reset" button on the thermostat, likely only accessible if you remove the cover.)
On high efficiency furnaces there's a vague possibility that the furnace computer could be similarly mucked up, and turning off the breaker for several minutes would generally reset that as well.
There's also the possibility that the "short cycling" is due to some sort of safety lockout on the furnace, either an overtemp sensor on a conventional furnace or something wrong with the induction fan pressure sensors on a high-efficiency unit. Look for an error code if your furnace has an error code display, and if it's "conventional" see if you can find the fan/limit switch and make sure it's not turning the unit off due to overtemp.
Of course, a surge could have damaged electronics, either in the thermostat or in the furnace. Thermostats are relatively cheap, so replacing yours (if you don't find a fix based on the above) may be the cheapest next move. Unfortunately, the furnace control boards are generally a couple of hundred bucks, so hope that isn't the problem.
Yesterday morning the unit reset itself to 62ºF during the middle of the night. No idea why. I thought it was the wife, but she said she didn't touch it. This morning (5:30AM) I found it at 62ºF again when I had set it to something else.
Further strangeness ... while it had reset itself to 62ºF sometime during the night, the actual temp reading on the thermostat was 69ºF. And while the outside temp was warmer (50º instead of 32º), this thing is either lying about the actual temp or it heated during the night and then reset itself.
Before replacing the unit, or swapping the unit with the one upstairs (Bob's good suggestion), I'll flip the breakers and pull the AA batteries for an hour and see what happens when I restore power.
White-Rodgers website is reporting the 1F80-361 is not discontinued and suggests no replacement.
Did you check the filter? Dirty filter = no air flow = heat exchanger overheats = premature shutdown. But that wouldn't have a thing to do with your thermo resetting...at least I don't think it could.
Anyway, take it from somebody who has forgotten often to change the filter.
Had one of the cheapie cardboard ones get dirty enough to get sucked into the fan. The metal screen messed up the fan motor.
Oh course I didn't check the
Oh course I didn't check the air filter. Just like basic math I have totally forgotten to check the simply things first. :) But, this doesn't explain the strange middle-of-the-night behavior.
I tripped the breaker and pulled the batteries from the thermostat for about 30-45 minutes yesterday. It now holds the desired temp during the day/evening. Sometime after 10PM it bounces between 62º and 70º.
At ~4L30 AM this morning I went down stairs and the temp reading was 67º and set to 62º, but I set it to 65º before going to bed. And within moments of that it automatically set the new temp to 70º and clicked on the furnace.
Its almost as if there is a program running. The manual says it features a permanent program ability--meaning killing electricity and pulling batteries may not clear any program.
Since it held the temp during the day yesterday after the circuit breaker tripping and battery pulling, I am no longer inclined to think its a furnace becoming too hot and cutting off early (short cycling).
What's not clear is that
What's not clear is that you're saying that the thermostat is "set" at 62. If by this you mean that the "target temperature" that you set with the buttons is 62 then it must be the thermostat resetting, not the furnace (unless you have a furnace that can "talk back" to the thermostat, and if that were the case your thermostats would be much more expensive).
I would suggest looking again for a reset button on the thermostat. And see if you can find the manual for the thing (maybe online) and see how you program it.
Sorry about that, Dan. When I get up in the morning the temp setting is 62ºF. This is the temp the heating unit must warm to. A program ran it to that new setting, not me. Yesterday I caught it like this and then heard a click as the program started a new program mode and set the tempt to 70º.
I just performed a system reset on the existing 1F80-361 stat. Current household temp is 68º and I set the temp to 70º with the HOLD feature engaged (bypasses program mode). Tonight when we go to bed, I'll set the tempt to 60ºF and when I get up I'll check to see if it held that temp.
Between tripping the breakers and pulling the batteries, and now a system reset hopefully it'll work normal as expected again. If not, I'll install one of the 261 units I just bought.
Is there a HOLD button on the thermo? Our programable you can "set" the temp where you want it but if you don't click hold it just goes back to its program setting.
Yes, there is. Before I tripped the circuit breaker and pulled the batteries for 30-45 minutes, the HOLD feature wasn't working. We'd set the stat to 70º and it wouldn't get within 4-5º. I removed the HOLD and it seemed to get there.
The next day I took someone's suggested and tripped the breaker and pulled the batteries and this seemed to allow us to get the daytime temp where we wanted it. But overnight, it has a mind of its own (running some program).
I just found the reset procedure for the 1F80-361 (hold both temp buttons along with the time button at the same time). HOLD is back on, no program is running, and we're testing it again to see if it holds the temp while we are awake, and checking it overnight to insure its not running a program.
BTW, I did pickup a couple of the 1F80-261 models as they replaced the 361. Its nice the shrunk the width of the case--makes for a visible redneck repair with exposed, unpainted wall. If the 361 isn't working come morning I'll just put a 261 in and be done with it.
BTW, trying to troubleshoot these past few days has been a challenge. The overnight temp 4-5 days ago was 32ºF outside. last night the overnight low was balmy 60ºF.
Weather needs to make up its mind on what season it thinks it should run as a program. :)
What, it only got down to 32 and you need to run the furnace?? ;)
I know, and the Yankee in me has waned. I'll give up some of those Yankee points. I'm still a Pats fan--nothing will change that.
It would seem that performing the breaker tripping, battery pulling, and thermostat resetting procedures have worked. It got down to 39ºF last night and the stat stayed put at 59º and did not jump to 62/70 as previously burdened.