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Inside blower will not turn off after outside unit turns off. Thermostat fan control set to auto. When I set it to emergency heat fan turns off after house is warm. Thermostat has not been changed. The only way to turn fan off is to turn the thermostat off.
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the blower unit or air handler is actually blowing air through the ductwork.
Here are the details of what to check in what order if your air condtioner or heat pump doesn't start at all when you set the room thermostat to call for cooling:
Check the Room Thermostat Temperature Setting: Set the thermostat to at least 5 degrees below room temperature. Our elderly mom has no patience with switches and controls. She regularly calls her air conditioning service company with a service request, sometimes late at night, because she has simply failed to set the temperature on the thermostat lower than the room temperature. Don't drive your A/C like our mother.
Check that the Room Thermostat is set to "Cool"not "Off" or "Heat". If the thermostat is not set to "cool" it is simply turning off your A/C. If the thermostat display is blank then it's not receiving power (for modern digital thermostats). Check that electrical power is on at the air handler and to the the low-voltage transformer that supplies power to the thermostat.
If the thermostat has power, check that when you set the thermostat temperature down at least 5 degrees below room temperature the thermostat calls for cooling. If it doesn't then check for broken or shorted thermostat wires anywhere between the wall thermostat and the control board at the air handler.
You can easily eliminate possible thermostat problems as a cause of failure of the air conditioner to start by simply eliminating the thermostat from the picture: disconnect the thermostat wires at the blower unit's control board and instead connect the two thermostat terminals directly together with a jumper wire. If the system starts then the problem is in the thermostat itself or in its wiring.
If the thermostat is working but the compressor condenser unit won't start, you could skip ahead
to COMPRESSOR / CONDENSER DIAGNOSTICSbut I wish you'd double check the remaining steps in this article first because there are some sneaky snafus listed below that might still be the problem.
Check that electricity is on for the equipment. Check all of the electrical switches and controls that can turn electrical power off at the indoor air handler or at the outdoor compressor/condenser unit. There are more of these switches than you might guess. Here's a list of what to check:
Electrical power switches and service switches outside by the compressor, inside at the air handler, and fuses or circuit breakers in the electrical panel. Don't forget to check that the access covers to the equipment are properly closed and latched. Otherwise a BLOWER DOOR SAFETY SWITCH could be keeping the equipment from running.
There are several other safety switches and controls, both manual and automatic that can leave an air conditioner or heat pump turned "off" such as a blower compartment door interlock safety switch, an electric motor overload or overheat switches, and a condensate tray spillage detector switch.
Some hard-to-find electrical switches on an air conditioner or heat pump could be keeping your air conditioner from starting, such as
a FLOAT SWITCH on Condensate Tray that could
be
causing CONDENSATE PAN SWITCH LOCKOUT - condensate spilling into an overflow pan that uses a sensor switch can be enough to shut down your air conditioner.
or
a blower MOTOR OVERLOAD RESET SWITCH could be keeping a fan motor from starting.
A bad or failed starter capacitor could also be leaving your system shut down, failing to start a blower, fan, or compressor motor.
See CAPACITORS for HARD STARTING MOTORS
Watch out: See A/C - HEAT PUMP CONTROLS & SWITCHES to be sure you have found and checked everymanual or automatic electrical switch on the system.
Check the electrical supply voltage. Even if electricity is on, if the supply voltage has fallen too far below the operating voltage range of your air conditioner it's likely that the system will not operate, particlarly, you may note that the compressor motor won't start.
See VOLTS MEASUREMENT METHODS
With a non heat pump it is a simple 24 volt AC control circuit. In the attic there is a relay that is actuated via the fan control wire directly from the thermostat. On the thermostat there is an auto/man switch that controls the fan. Manual the fan runs all the time. Auto fan turns on and off with the outside compressor.
If the system is not calling for cool and the fan continues to run the fan relay is sticking. common problem. Sometimes after running for several days the relay will stop sticking if not, replace relay.
If the system is calling for cool and the compressor stops I would still expect the fan to run until thermostat tells the A/C to off. Some compressor units include a safety switch or high-pressure cut-out switch A blocked internal valve bad control board or external fan in outside unit defective no air flow in outside unit.
High pressure cut out not good,
Suggest turning temp max cool and observe. If acceptable cool and the compressor runs without interruption all is good, except for the blower in the attic. Safely check relay in attic blower circuit.
Sounds like a set up issue on the tstat. You say this is a packaged unit, inside the machine you should find where the tstat wires hook up. Typically red is power yellow is compressor orange is reversing valve white is emergency heat green is blower. Put red and green together, test blower. Then red green and yellow, make sure blower works again. If blower runs both ways it's either the tstat wire or tstat itself. Make sure you are landing wires on dedicated heat pump terminals, make sure in settings you are set up for heat pump with back up electric heat and TSTAT CONTROLS THE FAN. Good Luck. Also if there is a switch on the tstat for gas or electric on the back you want electric.
I believe the unit you are describing is a heat pump. Heat pump are great when the temperature isn't below 30 With low ambient temps. outside it is much more efficient and comfortable to run aux. electric heat from the heat pump.
Let's start out by your statement that the fan would not run, then you changed the contactor, not it won't stop running.
I believe, based on your info, here's what you need to do. Kill power to the unit. The 2 wires bringing power to the outdoor unit should be on the top 2 terminals. The 2 fan wires should be on the bottom 2 terminals. This is providing that the contactor is mounted Vertical. The could be an outside chance that the unit has a short in it and you are getting voltage feedback somewhere.
Take another look.
Is there a setting on the thermostat for Auto or Fan? If so, make sure it is in the Auto setting. You will have a contactor that turns on the elements and a relay for the fan. Follow the wiring diagram to see which relay energizes the fan then unplug it to see if the fan stops.
The fan is controlled by a blower timer board located inside the air handler, or on older units it has a relay called (of all things) a blower relay. If these items were at fault I doubt removing the thermostat would cause the blower to go off. if bad causing this problem the blower would continue to run even with thermostat removed.
But it is also controlled by the thermostat.
You mentioned that if you remove the thermostat it cuts off. There are 2 switches on most thermostats. 1 has Cool, Off, Heat, and Emergency Heat (on a heat pump stat) 2 The other switch has On and auto (it is for the fan motor only)
I believe because it stops when you remove the thermostat that the switch on the fan is set to on possibly. It should be on auto-matic. This way the fan motor only come on with cooling or heating. If in the on it stays on all the time. If this is the case just switch to AUTO.
Or the thermostat may be wired wrong. The G terminal is where the fan motor gets instructions from the thermostat. Make sure its on G at the stat and the correct wire at the blower coil is being used for the corresponding wire going from the stat to the blower for G. Don't confues G for green it could be any color. The terminals are not for color but it makes more sence to make them color - letter identified. On the other end soemtimes the wires are not colored the same so look carefully.
Also a whisker of a thermostat wire could be touching inside the thermostat and causeing the motor to run 100%. Look carefully at this and see if it has too long of thermostat wires stickinhg on out under the screws to where they may tough other things.
If neither things stop or show the problem and it deffinately stops when thermostat is removed the thermostat is most likely bad.
If this helps you 1 way to make the repairs your\self or helps you realize you need a technician please rate mne as high as you can.
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