Posted: 9/16/2010 7:37:15 AM EDT
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AC/Heat question I had a strip heater installed in the Goodman 50K furnace a few years ago and it was rewired for the electric heat from the thermostat. I thought I changed it back to what it was but it's not working right. The A/C gets down to temp and shuts the blower motor off. When I turn the thermostat to heat the blower comes on right away and does not shut down when it reaches temp. It just stays on. The thermostat calls for heat , the igniter glows and the unit fires up and we get heat, the flame goes out once temp is reached but the blower just stays on. The guy who wired the unit and thermostat didn't have 5 wire so he used two sets of 3 wire. The downstairs furnace is identical to this one only 95K I though I wired the upstairs one just like that one but maybe I screwed up. |
| The problem is not with the furnace but rather the thermostat. When you have a t-stat set to electric heat, the t-stat controls the blower moter. When you set the t-stat set to gas heat, the t-stat allows the furnace control board to control the blower and the control board will turn on the blower after a predetermined amount of time. So the ignitor comes on, gas valve comes on, the flame is proven by the flame sensor then the clock starts ticking until it reaches a preset amount of time and then your blower motor comes on. In short, ensure your t-stat is set to GAS heat and not ELEC heat and your problems will be solved. |
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Quoted: The first thing I did was move the jumper from the elec to the gas.The problem is not with the furnace but rather the thermostat. When you have a t-stat set to electric heat, the t-stat controls the blower moter. When you set the t-stat set to gas heat, the t-stat allows the furnace control board to control the blower and the control board will turn on the blower after a predetermined amount of time. So the ignitor comes on, gas valve comes on, the flame is proven by the flame sensor then the clock starts ticking until it reaches a preset amount of time and then your blower motor comes on. In short, ensure your t-stat is set to GAS heat and not ELEC heat and your problems will be solved. That was even before the change back in wiring |
| OK, the next step is to look at the G terminal on your stat. The wire that is on the G terminal on th stat should be the same wire on the G terminal on the furnace control board. The G terminal controls the blower and it is not Ground like some people may deduce. You should be able to unhook the wire from the G terminal on the stat and your furnace blower SHOULD still work perfectly. Mind you this is only for heat mode. During A/C mode the stat controls the blower. Unhook the G terminal wire at the stat and turn on the heat. I'll wait... |