# Honeywell Thermostat Buzzing



## kbuckle (Dec 29, 2008)

Hi,

I just purchased a home (approx. 1 year old) which has the dial-type Honeywell thermostats installed. I've noticed on the majority of them, that when they turn on, there is a buzzing / vibration noise that lasts for 30 seconds or so. If I happen to touch the dial part of the thermostat, the buzzing stops.

I have two questions: What is causing the buzzing noise? Are the thermostats safe to operate in this manner.

Thank you.


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## Skipperjj (Dec 29, 2008)

The first step would be to check on the furnace itself to find a contractor sticker. The company that installed the unit should be listed there - the system might still be under warranty?
The second step would be to look into getting a newer programmable energy efficient style thermostat. Not sure whats causing that buzzing but it does not give me very secure feeling. New thermostats are pretty reasonable and you'll save a good amount on your power bills as well. 
At the same time you might want to establish a good rapport with a local HVAC company for at least bi-annual service calls to save you issues in the future. Hope thats of some help.


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## AllanJ (Nov 24, 2007)

Can you take the cover off the thermostat and see all the parts inside? Can you duplicate the situation by turning the dial ever so slowly one way or the other? I cannot think of any reason why the old round non-programmable mercury Honeywell thermostats would hum. Except possibly due to age of the bimetallic strip it took time for the glass capsule to tilt just right and the glob of mercury stopped halfway and an arc occurred in the capsule.


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## kbuckle (Dec 29, 2008)

Thanks for the comments. I have tried unsuccessfully to repeat the scenario with the cover removed. As I stated in the initial post, when I touch the dial, the buzz/hum stops. 

I have also replaced the thermostats with programmable type in the main living areas, but maybe it's time to change them throughout the house.

I should have mentioned earlier that the home has baseboard heaters and not a furnace has suggested in one of the replys.


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## BennettCKM (Mar 8, 2009)

Mine does the same thing, I touch it or hit the wall near it, it stops. I have an identical one in the other room that only has done it twice all winter, this one does it multiple times a day. So you are not alone!


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## AllanJ (Nov 24, 2007)

Could there be a loose connection inside, perhaps where the wires in the wall are attached to the thermostat?

For non-mercury models could the actual contact be dirty? You can use a small piece of ultra fine sandpaper or crocus cloth to clean the contact.


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## bernds (Jul 6, 2016)

In our company, we have these in every room (4 Floors, 6 rooms each).

They are ALL behaving in this way (not only 30secs, partially over 5 minutes long). They make this buzzing noise frequently and it is incredibly annoying.

It is not an exception that they show this defect, they ARE defective. 

Is there anyone who has tried something to stop it and can say he found a solution to this issue?

:vs_mad:


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## dmxtothemax (Oct 26, 2010)

Has anyone contacted Honeywell and asked for there advice ?


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## garyb (Feb 26, 2017)

I'm having this same problem. My house has electric baseboard heat throughout, with these really old 1980's thermostats from Markel Producs Co. I've replaced 4 of them so far with Honeywell CT410A but have only noticed a "buzz" in a couple of them. So I pulled them out and re-wired them w/ taped wire nuts and all, but the buzz continued... although it's not very often at all. It goes away if I rotate the dial a bit. The baseboard heaters seem to be working fine, regardless.

The Markel thermostats had a metal backplate, but these new ones are plastic. So I just capped the ground wire and pushed it into the box. I wonder if it needs to be somehow grounded better, or if it's just something wrong w/ the unit itself. Hmm. Maybe I'll try calling Honeywell tomorrow.


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## Justin_99 (Jan 23, 2017)

I would look at the electrical specifications of the specific model thermostat...

Then with a multimeter measure the supply voltage going to the thermostat.

These gizmos have "relays" sometimes and if a relay does not get enough electricity (what the specifications say it was designed for), then they may "buzz".


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## garyb (Feb 26, 2017)

Justin_99 said:


> I would look at the electrical specifications of the specific model thermostat...
> 
> Then with a multimeter measure the supply voltage going to the thermostat.
> 
> These gizmos have "relays" sometimes and if a relay does not get enough electricity (what the specifications say it was designed for), then they may "buzz".


Thanks for the suggestion, the specs say:

240V/120V
2640W @ 120V, 22A resistive
4576W @ 208V, 22A resistive
5280W @ 240V, 22A resistive
2-wire non-polarized connection.

I woke up this morning and it was about 90º in the room I replaced the thermostat. lain: So I'm wondering if I have the line and load reversed... The old Markel thermostat had 1 red and 1 black wire, but they weren't labeled. They had the black going into a pigtail of 2 other black wires in the wall, and the red went to a single black wire. So I'm thinking that maybe the red in the Markel was the load. The red in this newer Honeywell thermostat is actually the line. (And the neutrals are all twisted together and capped.)

If I did have them reversed, do you think constant calling for heat would be a side effect of that?

Thanks!


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## Justin_99 (Jan 23, 2017)

garyb said:


> ...If I did have them reversed, do you think constant calling for heat would be a side effect of that?


There are SO many different designs of thermostats, no way to tell without a schematic [circuit diagram] of the internals of the thermostat. And even then maybe no telling.

Some thermostats are a simple on/off switching design. Others are electronic and will be more picky about being wired properly.

I would just double check the instructions for the thermostat and get the wiring instructions for the heater - confirm it is wired correctly.

You can get installation instructions for heaters/furnaces many times from the manufacturer's web site. These will say how they should be wired.


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## garyb (Feb 26, 2017)

Justin_99 said:


> There are SO many different designs of thermostats, no way to tell without a schematic [circuit diagram] of the internals of the thermostat. And even then maybe no telling.
> 
> Some thermostats are a simple on/off switching design. Others are electronic and will be more picky about being wired properly.
> 
> ...


Thanks, I guess it's a pretty straight forward electronic single pole thermostat:










https://www.manualslib.com/manual/820077/Honeywell-Ct410a.html?page=2#manual

The prob. is the older Markel thermostat I'm replacing is like 33 years old (and so is the heater), so I don't really have any info on 'em. I think I'm gonna try reversing the red and black wires and see how that goes.


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## garyb (Feb 26, 2017)

I busted open the old Markel thermostat (going to throw it out anyway) and behind a cardboard piece, I found the black wire is labeled "common", so I think I should indeed wire the pigtailed black wires in the wall to the RED (line) wire on the new thermostat, and the other black wire to the load. I think I currently have them backwards.


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