Problem : I inverse out my control board and my furnace blower motor continues to run constantly. Fifty-fifty if I disconnect the thermostat wires it continues to run the blower. The merely manner I tin can shut the blower off is to turn the power to the furnace off. What could be the problem?

Respond : Nearly of the fourth dimension when a blower volition not shut off information technology is an open limit or rollout switch problem. Many furnaces (Bryant & Carrier) when showtime powered on volition run the blower for a infinitesimal or two and then shut off. This is a safety function of the furnace to eliminate any heat that is in the heat exchanger earlier the furnace begins its heating bicycle. If your blower is running all the fourth dimension… I would suggest that you examination your limit control and curlicue-out switches to brand certain they are not open. I have some pictures of limit controls and gyre-out switches below. If a rollout switch or limit is open up, the furnace thinks it has over-heated and the control board makes the blower run all the time to cool the furnace downwardly. You would need to test these with a meter to make sure they are non open. Is your control board flashing a blink code? If it is blinking a mistake lawmaking, effort to read what the lawmaking says the problem is. The fault code key is ordinarily located on the furnace door.Delight click here if you would similar to run across the limits and rollout switches that we sell.  Another problem that could cause the blower to run all the time would be a faulty thermostat that is sending 24 volts through the green fan on wire. Please make sure your thermostat is set to "Fan Auto" and not "Fan ON".  I would like to advise that you take the green wire off the "G" terminal on the control board and see if the blower stops. If the blower stops after the light-green wire is removed and so this indicates that you lot have either a thermostat problem or a thermostat wire problem. If the light-green and cherry thermostat wires are shorted out then this would crusade the blower to run all the time. A stuck relay (contacts welded shut) on the control board can crusade this problem besides. Below nosotros have a very informative YouTube video that explains how furnace limits and rollout switches operate and how to test limits and rollouts. If you have any other questions please feel gratis to email the states at: arnoldservice@gmail.com or comment in our comments department beneath. We would dear to have your business.

Limits

Above-two limits and one rollout switch in the middle:

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