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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a honeywell chronotherm iii, since yesterday was on

Customer Question

JA: Hi. What seems to be the problem?
Customer: I have a honeywell chronotherm iii
JA: I'll do all I can to help. How long have you been dealing with this?
Customer: since yesterday was on vacation and came back and found heater is not working
JA: Do you plan on doing the work yourself?
Customer: for the moment yes...because it looks to be a minor issue
JA: Anything else we should know to help you best?
Customer: the heater is pre-programmed
Submitted: 6 months ago.
Category: HVAC
Expert:  Phil replied 6 months ago.

Hello, the problem is with the thermostat about 1 time in 50 times, the other 49 times the problem is with the heating equipment that the thermostat controls. Regardless of any of of that, we can test the thermostat first, depending on you skills with tools and test instruments.

Tell me a lot about that so I can coach you most effectively.

Customer: replied 6 months ago.
I have seen the heating equipment above (top floor) and on display it is showing number 7. I will tell you everything from teh beginning: We moved into this new house about 3 months ago and the previous owners were using a pre-programmed heating schedule (for Honeywell Chronotherm iii) which says that during day, the heater will be off. We came back from a 10 days long vacation yesterday night (before leaving i set the temperature to 16 degree celsius). yesterday I came back and set teh temperature to 21 degree. The thermostat heaters in my house were working the whole night but the house was still cold.This morning after 9.00 clock, my heaters stopped working and on the thermostat display the heater shows 18 degrees with a flame sign. I try to increase the temperature to 25 degrees but the temperature is set to 18 now. It's quite cold in the house but i cannot increase the temperature. I read the manual for Honeywell chronotherm iii and tried fixing the issues but it does not work. My guess is that the pre programmed schedule is again ON by some means and I am not able to skip/shut it. In the heating equipment the air pressure is between 1.5 to 2.Can you help with any further suggestions? Should I reset my heating equipment?Kind Regards,
Expert:  Phil replied 6 months ago.

that should be the full manual along with a trouble shooting guide, we can begin here

Frist step press the 'Manual operaton' button on the lower left hand corner of the thermostat, follow the directions for resetting the temperature manually

Expert:  Phil replied 6 months ago.

Let me know how that goes

Expert:  Phil replied 6 months ago.

See page 2, its actually the 'hold temp' button at the lower left, press that, choose 'manual' then use the up and down arrows to manually set the temperature. Let me know how that goes

Customer: replied 6 months ago.
I have this same manual...have already pressed the Hold button at temp 22 degrees but the heater does not get gets set at 22 but no sign of heating...
Expert:  Phil replied 6 months ago.


I need the brand and model number of the furnace, and a close up photo of the wiring diagram glued to the inside of the blower access door.

Photo must be well lit and *exceedingly well focused. Post it here using the attach files link to the left of your send button.

We can go from there when I get back from the dentist

Customer: replied 6 months ago.
Hi Phil, Since the house was freezing, I had to hire a heating specialist who came over and fixed some issues/cleaned the boiler switch inside the heating equipment. Fortunately it's now working.
Expert:  Phil replied 6 months ago.

Hello, you found a good boiler man, be sure to keep his card.