Ask Experts Questions for FREE Help !
Ask
    cwb8's Avatar
    cwb8 Posts: 2, Reputation: 1
    New Member
     
    #1

    Jan 27, 2010, 10:48 PM
    Chronotherm IV Plus fan stuck on
    I keep changing the fan setting on my chronotherm IV plus thermostat to auto, yet it changes itself back to on, causing the fan to run continuously. Even when I set the system to "off" and the fan to "auto" it changes itself to "on" and the fan starts up. Is the thermostat defective? If not, how do I get the fan to stay in the "auto" position -- the only way I could get the fan not to run continuously is to pull the thermostat off the wall
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
     
    #2

    Jan 28, 2010, 12:11 AM
    Your no exact model number thermostat could have a stuck relay. Some of the Chronotherms use a relay for the blower circuit. If you check all the wiring and nothing is shorted out then it might be thermostat time but without an exact model I cannot look up anything.
    cwb8's Avatar
    cwb8 Posts: 2, Reputation: 1
    New Member
     
    #3

    Jan 28, 2010, 04:38 AM
    I've looked in the user manual and all over the thermostat but the only numbers I can find that may be the model number beyond the name is 32207415-024 0339 but that looks like a serial number. I can change the setting to "auto" and it will turn the fan off, but within a short term it automatically turns itself back to "on" so I don't think the relay is permanently stuck
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
     
    #4

    Jan 28, 2010, 07:21 AM
    You could be having a limit problem with the heating unit. Many times if the furnace limit or other control senses a overheat condition it will turn the blower on all by itself. In this case the thermostat will have no control over the blower since the furnace itself is causing the blower to operate.

    Label and disconnect the green wire at the furnace low volt terminal strip. The G or Green wire controls the signal from the thermostat to the furnace for A/C and manual blower operation. With the G wire disconnected the blower should not come on with the thermostat set to the OFF position for heat or A/C and also the off or auto position for the fan. This little test may help to isloate your problem. If this does not work then you will need a meter and trace down the offending part.

    You did not mention your furnace brand or exact model number so if it has a variable speed motor the test above will usually not work. Good luck.

Not your question? Ask your question View similar questions

 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

Honeywell Chronotherm IV Plus T8601D2019 - Fan [ 1 Answers ]

Honeywell Chronotherm IV Plus T8601D2019 -When I turn fan setting to ON position, I hear the thermostat click and the fan symbol comes on. However, the fan does not come on. Power is on. A/C technician indicates that I need a new thermostat. In the Auto mode the A/C compressor and fan runs.

Chronotherm IV Plus stuck terminal [ 5 Answers ]

I'm trying to install a Honeywell Chronotherm IV Plus (T8624D2004) on a conventional residential system: gas warm air furnace & A/C (both single stage). The wiring is pretty standard: red - R/RC; white - W1; yellow - Y1; green - G and a common wire from the other side of the transformer - C; unused...

My 16 year old honeywell chronotherm III is stuck flashing [ 1 Answers ]

My honeywell chronotherm thermostate is stuck flashing the temperature. How do I repair it or what can I replace it with?

Stuck fan control [ 1 Answers ]

How do I fix a stuck fan control in furnace?

Honeywell Chronotherm IV Plus Thermostat - Switch Fan to On [ 1 Answers ]

I have two zones on which there is a Honeywell Chronotherm IV Plus Thermostat. Right now I have a/c running on both units with no problem - fan is on "auto". However, my plumber needed me to turn the fan on both units from "auto" to "on". Seemed easy enough to change the setting, but it only...


View more questions Search