Tip & How-To about Heating & Cooling

What to check when you air conditioner will not stop running:

If you discover that your outdoor air conditioner and/or heat pump runs continuously even with your thermostat off and the indoor blower is off, the most probable cause is a stuck contactor. In most residential air conditioners / heat pumps, the contactor is the switch that allows voltage to your compressor and condensor fan motor; therefore, allowing them to run. The contactor allows line voltage (normally 208 - 240 volts) to pass through a set a contacts to your motor. The contacts pull in when the thermostat calls for Cooling and they "open" when the thermostat "satisfies". This is accomplished with the use of a low voltage coil. When 24 volts is applied to the coil, it creates a magnetic force that pulls the contactor in to close the contacts. When the 24 volts is removed from the coil, the magnetic force no longer exists.....a spring will force the contacts back "open" and stop the compressor and fan motor from running.
The contactor is considered a wear-n-tear item as, eventually, the contacts will wear and begin to "pit". Eventually, they will either pit so severely, they will not allow enough voltage through them to operate the motors OR they may allow enough voltage and then overheat and weld themselves together. Often times you can lightly tap on the contactor and it will "free" the contacts and stop the motors. Unfortunately, once the contactor starts "sticking" it is highly likely it will stick again. Therefore, it is recommended that the contactor be replaced at first sign of sticking or when the contacts show signs of damage/overheating via a visual inspection.

Here's a video that might be helpful to you. :-)




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3 Answers

My Goodman heat pump doesn't blow air through the vents into the house, but the fan comes on when the thermostat is turn on for the air conditioning


Check first that
  • the air conditioning equipment is turned on,
  • the thermostat is calling for cooling, and that
  • 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:
  1. 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.
  2. 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 DIAGNOSTICS but 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.

  3. 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.
  4. 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

Aug 22, 2017 | Goodman Heating & Cooling

3 Answers

When air conditioner turns off out doors I can still hear it running in the attic.


Are you sure you are hearing the air conditioner running, or maybe just the blower? The blower may continue to run to further dry the evaporator core and reduce the chances of mold and mildew formation.

-Rod

Jun 03, 2017 | Heating & Cooling

1 Answer

ice on coils of heat pump not cooling


Which coil?, indoor or out? Indoor coils freeze due to clogged filters, low freon, blower motor not working. Outdoor coil freezing could mean, in rare cases in cooling mode, reversing valve not shifting.

Oct 02, 2013 | Carrier 52CQ-312-4 Comfort Series Heat...

1 Answer

what is a E4 code mean


Error Code:
E1 Loss of communication between the Single Zone LCD thermostat and the mod-ule board. LCD will cycle between E1 and the previous mode setting. System
will shut down.
E2 Open circuit or out of range Indoor Temperature Sensor. Heating and cooling
operation will be locked out. Fan operation can continue to operate.
E3 Shorted Indoor Temperature Sensor. Heating and cooling operation will be
locked out. Fan operation can continue to operate.
E4 Open circuit or out of range Outdoor Temperature Sensor (select models). Heat
Pump operation will be locked out. Air Conditioner, Fan and Furnace operation
can continue to operate.
E5 Open circuit or out of range Freeze Sensor. Air conditioner mode of operation
will be locked out. Furnace, heat strip, heat pump and fan mode of operation can
continue to operate but displays the last temperature set-poi

Dec 18, 2012 | Dometic 3313192.000 White Single Zone LCD...

1 Answer

i have a heat pump unit. the fan will not come on. on the outdoor


ck capacitor on blower motor,ck relay,also make sure you have signal from thermostat to indoor unit

Dec 30, 2008 | Ruud UBHC Air Conditioner

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