BLOWER CONTINUES TO BLOW COLD AIR AFTER REACHING DESIRED TEMP.
IS THERE A LOW TEMP LIMIT SWITCH THAT SHOULD BE SHUTTING THE BLOWER OFF WHEN THE TEMP GET LOW AFTER THE FLAMES GO OUT. Blower continues to run after the temp gets cool for a long time and then shuts down.
GOODMAN MOD. GMP075-3 SERIAL 94040G4729 BTU 75,000
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Sounds like either a short between the G and R t stat wires or the relay in the control board is faulty. Easy way to check is remove the G wire from G terminal on the control board, if the blower stops, there is a short in tje t-stat wiring, if it continues to run a new control board will be needed since the relay is part of the board.
Hello, it could be shutting down on it's high limit switch due to a dirty air filter, dirty blower wheel, weak blower motor. Usually this would cause the furnace to shut down before it reaches the desired temp.
There are several limit switches in the unit there in various places in burner compartment. One on blower housing . One thing that I would try is replaceing your filter and turn the power off to the furnace and try starting the system after power is D/C for 5 minutes.
Hello, looks like you limit switch keeps opening because your furnace is overheating, Check your air filter and blower wheel to make sure it is not dirty and make sure you blower motor is moving at the proper speeed. Usually when air flow is cutoff the limit switch will open.
Is your 'Heater' you are talking about-- A furnace-- with a burner and a blower?
Either way-- We need to adjust a control that determines WHEN THE FAN RUNS--
Most furnaces have a section where the heated air collects, and there has to be a sensor in that chamber, that senses when that air is warm enough to circulate around--- and when the burner shuts off, the air in that area cools down, and the sensor should shut off the fan-
Can you find the Heated air area?-- and can you find a temperature control in that area?-- Can you adjust the control, so that it shuts off the fan when the air temp drops to 100- to 120 degrees F...
Tell us more about the type of furnace/heater we are workig with, so I can better help you-
There should be a limit switch and once the heater reaches the set temperature the blower gets signal from the limit and that turns on the blower. If you are not getting the blower until after the room is up to temp then it is coming on it may be the low limit is bad and it is cooling itself down on the high limit. If you are unsure of this please consult a heating service person, this is a serious problem that a trained service person should deal with. This can lead to a house fire!
I would look at fan limit switch. They are normally located in electrical cotrol compartment. If your are lucky you will have one thats adjustable. It would helpful if I knew is your home a mobile or modular home as they usually use a button type limit on fan and hi limit. It sounds to me like you may be having problems with fan limit which controls temp. that fan comes on . Often what happens is that switch scenses temp to turn on and then draws cold enough air on return air to shut back down until temp.rises again.If this occurs when unit first comes on or continues after burner shuts off you can get a limit switch with a higher temperature rating or one that has adjustable temperature range. Hope this helps you.Thanks.
Sounds like it could be your fan limit switch. Part costs about 20 bucks and is fairly simple to replace. This limit switch is a safety that prevents your furnace from over heating. Usually when your t/s is satisfied the blower runs for a little longer after the burners have stopped, and the reason for that is the limit switch. The blower is supposed to cool this limit switch to a certain temp. and once it reaches this temp it shuts the blower off. Yours is stuck:(
If the unit comes on and runs but then shuts down, that sounds like an indication of a high limit trip.
Most, if not all, furnaces have high limit switches that keep a constant check on the temp inside the furnace or air handler. On most systems, once this high limit switch has been made (got to hot), the limit switch breaks control voltage to the heating device (strips, gas, fuel, etc.etc..). The blower motor continues to run until the high limit has dropped in temp and reset itself.
On some models, the high limit is a manual reset, meaning you need to reset the switch yourself or shut the unit off and then back on to reset it.
Check all filters and replace as necessary. Check the coils and fan blades for dirt build-up and cleanliness. Check motor belt (if applicable). If all these fail to solve the problem, then your issue either lies within the blower motor itself not moving enough air for proper heat transfer. Or the high limit switch itself is failing.
It is rare that a limit switch goes bad. It is a safety control. If it is shutting off your furnace there is a problem that it is protecting you from.
If the limit switch is shutting the unit down your furnace is overheating. Check the filters. Check for any obstruction in the blower assembly. Check to see if you can raise the blower speed. Make sure all registers are open in the house. Your evaporator coil could be obstructed if you do not take good care of your filters.