Need input- important- old-fashioned thermostat

JaniceM

Well-known Member
I have a "vintage" manual Honeywell thermostat. Unsure of model, but round with gold-color outside and dial in middle. It's worked fine til recently.

Problem: the temperature sensor doesn't work. No matter how cold/chilly it gets in here, temp sensor stays at 78 degrees, so heat will not go on.

First, is there an easy safe "fix" for this? I don't like to mess with equipment that I know nothing about, especially if it could result in electrical shock or something. I'm guessing it needs reset, but don't know how to do that.
and second, could this problem have occurred because the fusebox was turned off and later turned back on?
 

I have a "vintage" manual Honeywell thermostat. Unsure of model, but round with gold-color outside and dial in middle. It's worked fine til recently.

Problem: the temperature sensor doesn't work. No matter how cold/chilly it gets in here, temp sensor stays at 78 degrees, so heat will not go on.

First, is there an easy safe "fix" for this? I don't like to mess with equipment that I know nothing about, especially if it could result in electrical shock or something. I'm guessing it needs reset, but don't know how to do that.
and second, could this problem have occurred because the fusebox was turned off and later turned back on?
First, pop off the top and blow, preferably with a can of condensed air like used on computer equipment. Look for any insect/cobweb stuff. It might just be dirty. Yes, I think the fuse box reset might have an impact - possible power spike?

Otherwise, try Googling for a manual online. I had the same thermostat for decades.

My S-I-L installed a new one for me last fall for $14.00 and it works great. Nothing fancy, but it turns furnace off and on when temp is right.
 
Another thought, JaniceM - Instead of canned air or breathe, if you have a balloon handy, blow it up and release it towards the innards. I really hope a cleaning solves your problem and you don't have to mess with replacement.
 

you could try this
https://www.google.com/search?q=honeywell+thermostat+manual+how+to+set&oq=vintage"+manual+Honeywell+thermostat&aqs=chrome.3.69i57j0i22i30j0i390l3.29291j0j7&sourceid=chrome&ie=UTF-8

If nothing else trouble shooting your thermostat might be found.

as for getting electrocuted

24 volts

The most common type of voltage from a central heating and/or cooling system is 24 volts (24Vac). The old thermostat may say somewhere on the thermostat that it is for 24 volt (24Vac) or maximum 30 volts (30Vac). If you see 120 Vac or 240 Vac on the thermostat, a low voltage thermostat will NOT work with your system.Jan 31, 2022

all in all try to locate what thermostat you have & work out solving your issue from there. And I'm NOT recommending you do anything you are not comfortable doing.
 
you could try this
https://www.google.com/search?q=honeywell+thermostat+manual+how+to+set&oq=vintage"+manual+Honeywell+thermostat&aqs=chrome.3.69i57j0i22i30j0i390l3.29291j0j7&sourceid=chrome&ie=UTF-8

If nothing else trouble shooting your thermostat might be found.

as for getting electrocuted

24 volts

The most common type of voltage from a central heating and/or cooling system is 24 volts (24Vac). The old thermostat may say somewhere on the thermostat that it is for 24 volt (24Vac) or maximum 30 volts (30Vac). If you see 120 Vac or 240 Vac on the thermostat, a low voltage thermostat will NOT work with your system.Jan 31, 2022

all in all try to locate what thermostat you have & work out solving your issue from there. And I'm NOT recommending you do anything you are not comfortable doing.
My S-I-L made me switch off the power at the panel before changing mine. Probably always a good idea!
 
if it is old...I would really think about replacing it, rather than fixing it. The new ones don't cost all that much. I mean, unless there is something very unique to that unit which would require extra expense.

Here's one Honeywell thermostat ---- only $60

https://www.amazon.com/Honeywell-TH...ocphy=9003533&hvtargid=pla-334512574994&psc=1
Sorry I didn't think to mention this is apartment (rental). Landlord doesn't know how to do anything, maintenance guys and contractors quit, so I'm kinda on my own with stuff.
 
Our house originally had one of these Honeywell thermostats. It quit working after about 5 years, I took it apart and found that there was a set of contact points which had become pitted, and wasn't making good contact. I cleaned up the points with a fingernail file, and it worked ok again. Shortly after, I replaced it with a White Rodgers/Emerson programmable thermostat, and no more troubles, since.

Unless a person has some electrical skills, it's not worth fooling with. Have it replaced.

https://www.homedepot.com/p/Emerson...e-Stage-Digital-Thermostat-1F80-361/300771423
 
Knowing what to ask about on google can be a challenge. BUt if you can ask in a way that Google has info on it's like magic.

I typed in this.

how to find the model # of a vintage manual Honeywell thermostat

https://www.google.com/search?q=how...rome..69i57.6856j0j7&sourceid=chrome&ie=UTF-8

Not only that info popped up but other good info to help was there to chose from.

People also ask
How can I tell what model my Honeywell thermostat is?
How do I find model number on my thermostat?
How do I find my old Honeywell thermostat?
Can you replace an old Honeywell thermostat?

As a DIY kind of guy replacing a thermostat wasn't that big a deal. BUT JonSR77 post #15 is worth reading and heeding if anyone is the least bit unsure.
 

The Dangers of Installing Your Own Thermostat & Why You Should Have a Professional Install It​



"Potential consequences of improper installation could include: Electric shock. Blowing a circuit breaker. Damaging the thermostat unit, the electrical system or even the AC/furnace unit itself."

https://www.smitssolutions.com/2018...why-you-should-have-a-professional-install-it
The main danger is depriving some overpaid electrician of the opportunity to rip you off. OK, I studied electrical & electronic engineering at uni so I'm happy to tackle such tasks, but in most cases domestic wiring is not rocket science and well within most people's skill set.
 
The main danger is depriving some overpaid electrician of the opportunity to rip you off. OK, I studied electrical & electronic engineering at uni so I'm happy to tackle such tasks, but in most cases domestic wiring is not rocket science and well within most people's skill set.
Every time I hear the Spousal Equivalent say, "No need to call a ________, I can do it myself ", I start to sweat.

I know that means I will be without electricity or water or a working toilet, or a non-leaking roof or.......until I DO call a ________.
 
Well, guess what- new landlord/manager doesn't understand what's going on.
This is what happened (before my original post): previous landlord was doing some work in apartment, shut off all the switches in the fusebox; said he didn't think one went to anything and left it off. I assume that's what disconnected my heat. I turned the switch back on, but thermostat still does nothing. Furnace is working properly.
The weather has become cold, is supposed to get worse, and I need heat!!!
 

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