- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
check the fan setting on your thermostat. On means always on, auto/int means only comes on during heating/cooling. if the thermostat is set to auto / int and the fan keeps running? you may have a bad fan relay switch. It may be integral on the primary control board of your unit.
Check the fan relay. These relays are used to cut the fan on and off when the thermostat is set in
the air conditioning or heating mode or when you move the thermostat to the "Fan On"
position. The low voltage usually the green thermostat wire is wired to terminal
#1. The low voltage common wire to terminal #3. One line voltage wire is
attached to terminal #4. The high speed blower wire usually black is attached to
terminal #2. When the thermostat calls for air conditioning or "Fan On" the 24
volt coil is energized, the terminals 4 and 2 close. This causes the fan to come
on in high speed. When your home cools down and the thermostat cuts the air
conditioner off, the low voltage coil terminals 1 & 3 are denergized, and
the fan goes off. Sometimes these little relays stick which causes the fan to
run all the time or will not make good contact, which causes the fan to not run
in the "Fan On" or air conditioning mode.
The model of T-stat you gave comes up as a discontinued model on Honeywell's web site, but it looks to be a manual stat that type of stat would have to be wired with a summer winter switch with electric heat, allowing it to turn on the fan with a call for heat. If yours is a programmable T-stat you would need to select electric heat or in the installers set up change the default setting for fan from unit controls fan in heat to thermostat controls fan.
Okay did you check your thermostat to see if you have the fan switch on auto? The switch must be on auto or the fan will continue to run. If the thermostat fan switch is on auto then there is a malfunction in the thermostat probably. You can go to your forced air unit and on unplug the unit. That way it will not turn on at all, because the forced air unit is controlled by the thermostat. Hope this helps.
The fan is controlled by a blower timer board located inside the air handler, or on older units it has a relay called (of all things) a blower relay. If these items were at fault I doubt removing the thermostat would cause the blower to go off. if bad causing this problem the blower would continue to run even with thermostat removed.
But it is also controlled by the thermostat.
You mentioned that if you remove the thermostat it cuts off. There are 2 switches on most thermostats. 1 has Cool, Off, Heat, and Emergency Heat (on a heat pump stat) 2 The other switch has On and auto (it is for the fan motor only)
I believe because it stops when you remove the thermostat that the switch on the fan is set to on possibly. It should be on auto-matic. This way the fan motor only come on with cooling or heating. If in the on it stays on all the time. If this is the case just switch to AUTO.
Or the thermostat may be wired wrong. The G terminal is where the fan motor gets instructions from the thermostat. Make sure its on G at the stat and the correct wire at the blower coil is being used for the corresponding wire going from the stat to the blower for G. Don't confues G for green it could be any color. The terminals are not for color but it makes more sence to make them color - letter identified. On the other end soemtimes the wires are not colored the same so look carefully.
Also a whisker of a thermostat wire could be touching inside the thermostat and causeing the motor to run 100%. Look carefully at this and see if it has too long of thermostat wires stickinhg on out under the screws to where they may tough other things.
If neither things stop or show the problem and it deffinately stops when thermostat is removed the thermostat is most likely bad.
If this helps you 1 way to make the repairs your\self or helps you realize you need a technician please rate mne as high as you can.
You have a blower relay in the furnace that's probably bad. In the heat mode the blower is on a temperature relay, in cooling mode the blower has to come on immediately so there is another relay for cooling. The green wire on the thermostat feeds that relay, so if you go to the furnace and shut the power off and find the green wire from the thermostat that feeds that relay and replace it, being careful to mark all the wires before removing them, also the relay terminals have numbers for identification.