How To Look At A House
McGarry and Madsen's home inspection blog for buyers of
site-built, mobile/manfuactured and modular homes
How can I tell whether the condenser (outdoor unit) is an air conditioner or heat pump?
Friday, June 15, 2018
A condenser that only cools is called a “straight cool” unit, and there are several ways to tell the difference between a heat pump and straight cool condenser. Probably the easiest method is to check near the bottom of the data plate on the side of the condenser for the words “HEAT PUMP,” or “CENTRAL COOLING AIR CONDITIONER“ or “CONDENSING UNIT” for straight cool air conditioners.
A second way to figure it out is to Google manufacturer’s name and the model number from the data plate, which will usually tell you what type of unit you have, as shown below. Both these methods assume that your data plate is still intact and readable, which is sometimes not the case for an older machine.
If the data plate is no longer legible, you can look through the top grille into the center of the condenser for a horizontal brass tube, like the one shown below. It’s the reversing valve, which switches the direction of refrigerant flow to to change from cooling to heating, and will only be seen in a heat pump. Usually, the reversing valve is readily visible, but some manufacturers conceal it behind an access panel. So the presence of a reversing valve indicates that you definitely have a heat pump but, if you don’t see one, it doesn’t automatically mean the unit is a cooling condenser. Onward to a fourth strategy.
Put the thermostat at “HEAT” and raise the setting ten degrees above the current room temperature. Make sure it is not set at “EHEAT” or “EMER HEAT.” Then, after you feel heat coming out of the registers (vents), go outside and see if the condenser if running. There may be a few minutes time delay for the system to turn on. When you have a heat pump, it will be operating and blowing cold air. If silent, then you have a cooling air conditioner with a heat strip in the air handler.
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To learn more about heating and air conditioning systems, see these other blog posts:
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