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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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My condo has a Honeywell thermostat that does not display

Customer Question

My condo has a Honeywell thermostat that does not display the model on it. From the images it appears to be a T6570 or T8570, based on online pictures.
The room temp stays put at around 25-27deg C always making it unbearable to live. I reduced the temp to 18degs but it doesn't seem to have any affect. I think the thermostat is itself OK but an internal programmable parameter is incorrectly set.
Could you advise what should the folling be set at if I want to maintain a room temp of 20-22deg? Much appreciated!
db,OP, uC, uh, CO, HO, CL, HL
Submitted: 9 months ago.
Category: HVAC
Customer: replied 9 months ago.
Image attached
Customer: replied 9 months ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Phil replied 9 months ago.

Hello, if you got that error notice out of the blue, and not after you had adjusted the thermostat... the thermostat is most likely failed... it will be easier to replace it than anything else.

Tell me a lot about your skill sets with electrical devices, I can coach you on further trouble shooting and can buy a new thermostat for that in the $50 range.

If you feel capable in those regards, ***** ***** front part of the thermostat off of its wall mounted sub base, and tell me which color wires attach to which terminals (designated R, W, Y, G and C etc)

We can go from there.

Customer: replied 9 months ago.
I am a tenant and he owner lives away. Won't be possible to replace unit without rejecting out config issues. If you could guide me the thermostat settings for the parameters I lliste, to maintain a temp of 20degC that would be v helpful to start.
Expert:  Phil replied 9 months ago.

That will work, however I really do need you to tell me if this issue came up out of the blue, or *after* you had been attempting to program the thermostat...that is crucial to the diagnosis.

If we attempt to reprogram a broken thermostat it would be many fruitless hours wasted.

Expert:  Phil replied 9 months ago.

There is one other issue, if you can pry the front of the thermostat from its wall mounted sub base you will see the thermostat model number stamped on the back beginning with RTH.......

Customer: replied 9 months ago.
DB:2 deg C
I was never comfortable with how cold or hot it used to get in the condo and there is no Cool oR Heat switch to toggle tool. I have been toying with the settings to try and adjust so my settings may have caused this however I cannot be sure. It became noticeably uncomfortable now because the building has started circulating heat with the start of fall. The only options for me are either switch the unit off or let it blast hot air at 26deg. The building mgmt says it should go down till 69degC but I am struggling to make it work. The settling on the thermostat are as follows. The unit is kind of stuck and I cannot pry open the front cover. I will risk trying harder if this is absolutely essential to proceed.UC: 25degC
UH: 18deg C
HO: 0
CL: 10 deg C
HL: 30degC
ES: 1
RT: 1Please help!
Expert:  Phil replied 9 months ago.

Hello again, interfacing with an existing building system, that is either in cooling mode, or heating mode..... but not able to switch between the two easily, limits your options and sticks you with the situation you have described unfortunately.

Toying with your thermostat control will not over come these built in limitations....even a brand new thermostat will not over come these basic built in limitations.

There are also the limits the building owners set on heating, they do this to save tens of thousands of dollars per year...

In many buildings the main boiler in the basement is set to go OFF when the temperature outside is above 67 or 70F.... so that no matter what you do with your thermostat there will be no heat. That is 100% a deliberate building owner strategy (and recommended by US government energy conservation energies)


because if the building is heated to 72F on a cool morning, then the building warms up in the afternoon, extra heat has to run in the morning (costing thousands of dollars in a large building), then because the building was already warmed to 72F, cooling must come on sooner that it normally would if the building had not be pre heated. (costing more thousands of dollars).

Let me know if my explanation has made any sense to you.

Solutions: Buy one or two $35 portable electric space heaters and use those to warm up the rooms you spend a lot of time in.

Regarding the thermostat,

Honeywell makes a wide range of models that look the same but program *differently... your best bet if you cannot get me the the full 10 digit model number is ***** ask the building super come and reprogram your thermostat he has done this many times and should not mind doing it for you (if he is a nice guy)

Try these programming instructions on your thermostat, there are also instructions on how to remove the thermostat from its sub base.

We can go from there.

Your building superintendent will be in