Follow these troubleshooting steps to do that. This shuts the furnace down and prevents your thermostat from calling for more heat. If the furnace was in the middle of a heating cycle, wait 3 to 4 minutes for the blower fan to stop running. Did your furnace fan stop blowing? If your fan is set to ON, it will run continuously, regardless of whether your furnace is heating or not. Tip: Avoid setting your fan to ON, it wastes money because it forces the fan motor to run constantly. Please look through those steps and let me know what you find.
The simplest and most straightforward test is to disconnect a thermostat wires at both ends and then working from each end test for any continuity between any pair of them. Let me know what you find. Assumption: the W, Y and G should have no continuity to C ground , or to each other--correct?
I found a discussion in another forum with same symptoms intermittent failure of airhandler to stop blowing after reaching setpoint temp , where poster found the G line was left 'floating' as opposed to being grounded at setpoint shutdown.
He mentioned a 5K. I just installed a K across G and C. Should only load 24VAC transformer with an additional 24mA. A cooling cycle just completed--system cooled to setpoint, thermostat clicked, and about a minute later, airhandler stopped blowinggood!
Fingers crossed that this solved it! I got that, Steve, but I'm not clear on whether or not you found that by disconnecting the TT right at the air handler was done at a time when the AHU was running when you think it should not. Taking that step not only rules out a bad thermostat but also mistakes in thermostat wiring and also the more-subtle problem of thermostat wires that are shorted together somewhere enroute.
I've already disconnected the thermostat, and replaced it with a brand new one Have you tried disconnecting the thermostat right at the air handler? That can rule the thermostat out. I've got the same problem, as posted On by Forrest.
Figured it was the blower delay relay board; replaced it and all seemed ok for a few days. It started up again today. I called Goodman and a tech suggested the thermostat might be defective.
I had a new-in-box thermostat on hand, and wired it in. It's doing same thing--seemingly random failure of airhandler to shut down, after reaching set-point temp. I'm wondering about either the control wiring, or the 24 volt transformer. We had a power outage a few days before this trouble started, and wonder if the transformer might have been zapped, and isn't putting out 24 VDC.
The other possibility is wiring--if there's some random short or open, responding to equipment vibration or? How to check the control wiring? What wires should be 'shorted' to each other, or to ground, during different operating states? Bill Your service tech might check for a bad control board or ice blocking on the cooling coil.
I have a 15 sheer unit that blows strong and then weak, but continues to go up and down when activated at Temp setting. I mean it blows loud then soft then loud but maintains temp. Whats happening can someone tell me what can I do?
If the blower previously would run in high speed then I suspect a failed relay or control board. Why won't the blower turn on high on my Goodman heat pump and Goodman furnace while in the cooling mode. On by mod - blower motor on air conditioner will not shut down. I put in a new control board,that didn't work.
Tab Your heating service tech may find a bad switch or control or even a thermostat set wrong or shorted thermostat wires. She might check the diagnostics above on this page first. It will work for half the day and then the other half of the day it will not shut off. If I flip the breaker off and right back on the fans stays off until the next cycle. On - by mod - check dip switches or jumpers on fan controller.
First let's identify the exact brand and model of heater and then look at the manual to see what settings are available. On most equipment there's actually a user operable switch that will turn the fan to run continuously. But on some it might be a dip switch or jumper.
The other place to look of course is at the thermostat. You can rule out the thermostat by disconnecting the thermostat wires entirely at the heater. If the fan keeps running then it's not a thermostat setting. Thank you for getting back to me. You mean you think it's the ECM problem bad or set that way as well? I agree with you that typically there's either a switch set somewhere or a shorted wire or bad control. Thank you for all the very very helpful information found on this website!
This is what I have gathered so far:. I suspect the ECM module is programed to run the motor non-stop, by the builder or previous owner? Program Or what else could be the problem here? Thank you again! If the button is pressed in, the switch is set to Manual and is forcing the fan to run continuously. Have a furnace fan that runs continuously? Step 1: Locate your fan limit switch Your fan limit switch is located inside the furnace panel cover, usually near the upper right corner.
Step 2: Make sure the white button is NOT pressed in Your fan limit switch will have a small white button on the lower left corner. Two problems that could cause your fan to run without stopping include: A bad fan limit switch that needs to be replaced Bad thermostat wiring Need help from an Atlanta furnace tech?
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