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Ask Tim Cooke Your Own Question
Tim Cooke
Tim Cooke,
Category: HVAC
Satisfied Customers: 1175
Experience:  Owner at Self-employed
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One of the controls on my hot water and heating is bleeping

Customer Question

Hi One of the controls on my hot water and heating is bleeping about every 4 minutes - is it trying to tell me something?
JA: What's the brand and model of your HVAC unit? How old is it?
Customer: The main control is ST9400A and the control on the circulation pump is ST9100C - I guess they are about 5 to 8 years old. They both set themselves when the clocks change if that helps.
JA: What have you tried so far?
Customer: Nothing
JA: Anything else we should know to help you best?
Customer: I dont even know which one is making the noise - its like a low battery signal.
Submitted: 6 months ago.
Category: HVAC
Expert:  Tim Cooke replied 6 months ago.

I've never heard a ST9400A programmer make any beeping noise, and it's backup battery isn't replaceable. The same applies to the ST9100C timer.

Are you certain that the beep isn't from a smoke alarm?

Customer: replied 6 months ago.
sure. It’s too quiet for that. Ther is a thermostat control which over rides the other controls if the room temperature is too high. It is also a Honeywell product but has no serial number
Expert:  Tim Cooke replied 6 months ago.

I've heard smoke alarms make a beep that is so quiet it's almost inaudible. Personally, I would unmount the smoke alarm and wrap it in a coat or blanket, and see if you can still hear the beep at the same level.

It sounds like you have a Honeywell room thermostat, in which case it's not overriding the programmer. The room thermostat actually switches on the heating, indirectly, when the room temperature drops, and switches it off when the temperature reaches the setting on the thermostat.

Expert:  Tim Cooke replied 5 months ago.

Hello, did you find the source of the beeping?

Do you have a CO alarm?