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Re: Honeywell Smartfit Control Unit
You need to either call an electrician if your unable to, or do not have the knowledge to troubleshoot electrical circuits, or, get a multimeter and see that power is coming to the furnace/heater.
Reply back what type of heating unit you have (gas or electric), any other symptoms you've observed (including has the system ever operated before, and what changes may have been implemented to cause it not to operate) and the model, and we can be of more help to you.
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If its a standard split cooling system you should have a control wire that connects the indoor unit to the outdoor unit. That control wire has 2(or more) small wires and normally red is the hot(24volt) and white is the common. Power from red may be shorting to ground or touching the metal on something. It could be the wire touching another wire causing a short. Or if the outdoor unit has safety switches such as a low or high pressure switch, the wires to them may have rubbed against the copper tubing inside the unit causing a short to ground. It could be the electrical contactor or any circuit circuit board it may connect to. Most the time I find that the control wire (small wire) will be pulled on or chewed at the outdoor unit. Something can pull on it and cause it to ground where it connects to the unit behind the control panel. Be sure to be safe!!! A bit of experience may be needed. A good tech can usually find a short in 10 mins.
There are other universal replacements but if it was me I would stick with the honeywell parts. I know they are more expensive but in your instance where you already have a problem that is causing the control panels to fail I'm afraid you would make it worse by using other then factory replacements.Thank you
Hi, check the wire connections to make sure the Red wire is good and tight. This is only low voltage, so don't worry about getting zapped. If all wires are tight. you may have blown the control fuse at the indoor unit. Go to it with a good light, pull the panels and look for a circuit board that the thermostat wires connect to. Depending on the age, you should have a plug in fuse, like a auto fuse that will be a 3 to 5 amp fuse. See if it is blown. If your not sure, replace it anyway. Put the panels on correctly, and see if this solves your problem. If so, don't forget to rate me :) Shastalaker7 A/C, Heating Contractor
I had exactly the same problem.F4 code says the control valve has jammed --- but it hadn’t. I ended up having to swap out the room controller and the base unit (I bought the pair since it was winter and I couldn’t ‘eff’ about) On investigating (well, you have to don’t you?) I could find no obvious fault but did notice that a large electrolytic capacitor was across the actuator motor. Since these things work by reversing the supply polarity to the motor to drive the actuator one way and the other it strikes me as strange that a polarity sensitive component, one that must be always connecter positive to positive, is used in the way that it is. Bottom line, tough luck, mate.Replace the units.
If it is showing A/C it has lost control voltage or the 24 volts to operate. Need to check line voltage to furnace and check the control board, if a late model unit, most will have a 3 amp fuse mounted in the control board. If blown need to find out why??
You could possibly have an ignition problem. The controller will go into a lock-out condition if flame is not established. Turning the temperature control down and then back up may be serving to reset the control system so it tries again.