Why your

heat pump or air conditioner

won't run or shut off.

   If your air conditioner or heat pump won't shut off unless you pull the fuses or turn off the circuit breaker. You probably have a stuck contactor. The contactor is the name we give to the big relay that controls your air conditioner, heat pump or other large electrical device.
    If the indoor blower fan will not shut off either then the problem is NOT the contactor in the outdoor unit but a problem with the thermostat or the wiring to it either at the subbase or the furnace. Before replacing your thermostat you should isolate the cause of the problem or it will persist. Look for wires touching or cut too long.
    A contactor or relay is an electrical device that takes a control signal ussually 12volts DC, 24, 120, 208-230 volts ac and creates a magnetic field to pull in a set of contacts
    The contactor has steel contacts that are plated with silver. When the silver wears away you have just plain steel and the steel will weld itself together. Sometimes if you whack the contactor with a screw driver you may free it  for a while but the problem will re occur. This problem is especially a problem when a piece of equipment has not been run for a period of time.
    You can also have problems with spiders building nests in the contactor; the silk is an insulator and will prevent electricity from flowing.
    Replacing a contactor is a simple matter and they are readily available.
 Costs vary from about $40 installed to several hundred dollars depending on the size and current carrying capacity.
    Contactors are also used in motor starters. Brand names include Allen Bradley, Cutler Hammer, Telemecanique, Furnas, Honeywell, General Electric (Mars), Robershaw, White Rodgers, Steveco, ITT and others.
    Used on the following brands: American Standard, Amana, Arco, Arco-Air, Bryant, Carrier, Coleman Evcon, Comfortmaker, Day/Night/Payne, Dunham-Bush, Fedders, Fredrich, Goodman, General Electric, Hotpoint, Heil, Intertherm, Janitrol, Kenmore, Lennox (Armstrong, Johnson Air-Ease), Miller, Modine, Nordyne, Rheem/Ruud, Sears, Stewart Warner, Trane, Williams, White-Westinghouse, Whirlpool, Weil Mclain, York, (Frasier Johnson/Borg Warner) and others.

    To send us a question about your unit please use our cooling Fill Out Form.
    For general heating questions please use this form
Images of one pole contactors. 3 phase contactors can have as many as three or four poles.
Image of 1 pole contactor (Honeywell brand). Contactors can have as may as 4 poles. Most single phase contactors have 2 poles and three phase contactors will have 3 poles plus some auxiliary contacts.

Definitions:
  1. Blower: usually a squirrel cage centrifugal air moving device. Will move large volumes of air relatively quiet. Will use less energy with more back pressure.
  2. Fan: a paddle type air moving device used where noise is not a major consideration. Will use more energy with more back pressure.
  3. Combustion blower: A blower used on high efficiency gas furnaces or oil burners to move combustion air. usually 1/20 to 1/6  horsepower.
  4. OEM: Original equipment manufacturer.
  5. Horsepower: 746 watts
  6. RPM: revolutions per minute.
  7. Service factor: the extent to which a motor can be safely overloaded beyond its name plate ratting without over heating.
  8. Air over horsepower: The rating of a motor assuming air flow through the windings usually as a result of the air moving device.
  9. SAE: Society of Automotive Engineers.
  10. High efficiency furnace: Furnace that uses over 85% of the energy in the gas.
  11. Condensing furnace: Gas furnace that uses over 92% of the energy in the gas and condenses the gas into liquid condensate and hot air. If your furnace has PVC pipe venting it then you have a condensing furnace.
  12. Evaporator. The part of an air conditioner or refrigeration system that gets cold due to evaporating refrigerant.
  13. Condenser. The part of an air conditioner or refrigeration system that gives off heat by condensing the refrigerant.
  14. Indoor coil or unit. On a heat pump unit we call the inside section "indoor" so as not to confuse it with the evaporator on an air conditioning system.
  15. Outdoor coil or unit. On a hat pump we call the outside section "outdoor" so as not to confuse it with the condenser on an air conditioner.
    This page will be updated soon
 Good Luck Scott
To identify the components of your gas furnace and gas valve system click here.
If your heat pump forms ice outside in the heat mode click here.
If your air conditioner or heat pump ices up in the cooling mode click here.
If you have water leaking problems click here to solve it.
For other heat pump or air conditioning problems click here.
For other heating system problems click here.
 Any other questions feel free to contact us by any of the means below. good luck Scott.
    If you were looking for Ice Machine repairs click here.
Written By:  Scott Meenen N3SJH of:
G&S MECHANICAL SERVICES.
Specializing in Mechanical, Controls and Electrical Modifications Of
Heating, Air-conditioning, Refrigeration, Cold storage,
Ice Production and Food preservation. Anything having to do with Heat and Energy.
Serving MD, DC, and Northern VA.
Contact us by pager: 1-877-467-2914

Page us by e-mail 4103560613.3732505@pagenet.net 240Chrs max.
Paging service availiable through contract select.

Email us at: jsmeenen@toad.net

                 This text written by: Scott Meenen * G & S Mechanical

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