What happens when a heat pump system in the heating mode goes into defrost?

When the heat pump goes into defrost mode, it momentarily reverses operation and goes through the “cooling cycle.” This forces warm air through the outdoor coil, warming it temporarily to remove the frost. It will continue in the defrost mode until the outdoor coil reaches 57 degrees.

When the heat pump is in the defrost cycle the auxiliary heat will be on?

The defrost cycle lasts 30 to 45 minutes and when the unit sensors sense the ice has melted the unit then reverses into the heat mode, the condenser fan motor starts and the auxiliary heat goes off.

When should AUX heat come on with heat pump?

AUX heat refers to your heat pump’s “backup” electric resistance heating. This heat setting should only kick on when the heat pump can’t produce enough heat to warm your home or if your heat pump goes into defrost mode.

How do I get my heat pump out of defrost mode?

Run the Fan
One thing you could try to do to unfreeze your heat pump (if your system is equipped with it), is simply turning on the fan. Blowing air will usually thaw the equipment within 60 minutes. If the outdoor temperature is particularly low, you can set up the fan on an exhaust setting.

How long should a heat pump run in defrost mode?

Generally, heat pumps will defrost regularly when frost conditions are occurring. However, the frequency of defrosts should be no more than roughly every 35 minutes. The length of time the heat pump will defrost will vary, but ordinarily it should not take longer than 10 minutes.

Does fan run during defrost cycle?

The air handler fan is required during defrost to prevent the evaporator coils from freezing up.

What temp should AUX heat come on?

Your auxiliary heat should turn on when the outdoor temps are near 30° Fahrenheit and below. This temperature is when your air-source heat pump struggles to obtain enough heat from the outside air to warm your house. Therefore, when the temperature is below 30 degrees, AUX heat is needed to supplement your heat pump.

Should heat pump and AUX heat run simultaneously?

The system is designed so that both can operate simultaneously. As long as the HP is producing some heat, it’s more efficient to use the HP for whatever Btu’s you can garner and allow the aux heat to be just that, auxiliary rather than primary.

Does heat pump run when auxiliary heat is on?

That’s exactly what the auxiliary heating setting does for your home’s heat pump system. Basically, if your heat pump is struggling to maintain its goal temperature, your aux heat will turn on and give your heat pump a boost. Aux heat will kick on when your heat pump cannot deliver enough warmth to heat your home.

How do I know if my heat pump is defrosting?

You’ll know the defrost cycle is activated when the heat pump switches from heating to cooling. You may hear the reversing valve when this occurs. Another sign the defrost cycle is running is the indoor unit will run but the outdoor fan will be off.

What controls the defrost cycle on a heat pump?

The Typical Cycle
There is a special thermostat or sensor of the defrost cycle system, often referred to as the frost thermostat. It is located on the bottom of the outdoor coil where it can detect the temperature of the coil.

How do you know if your heat pump is frozen?

Signs of a Problem
It has been frozen over for a long period of time. The top of the unit and inner coil seem to be covered in ice. The defrost cycle does not seem to be activating. Air is not being pulled into the fins of the unit.

What are the most important things to understand about the defrost cycle?

There are a number of factors that influence how often a unit will go into the defrost mode, including: The outdoor temperature and humidity. The amount of heating load the system is trying to deliver. The condition of the heat pump.

How often does the defrost cycle run?

Cycle Defrost: The refrigerator fresh food section defrosts automatically by means of a thermostat affixed to the evaporator coils every time the unit cycles off (usually every 20-30 minutes).

Why is the auxiliary heat necessary during the defrost stage?

A defrost control tells the reversing valve when to send hot refrigerant outdoors to thaw the outdoor coil during the winter. During the defrost cycle, your auxiliary heat takes over, which reduces the heat pump’s overall efficiency by up to 10 percent.

Why is the Aux light on my thermostat?

“Aux” is short for auxiliary heat. If a heat pump is having a difficult time coming up to a certain temperature quickly due to extremely cold outdoor temperatures, the “aux heat” indicator means that a secondary heat source (generally gas or electric) has been deployed.

How do you know if your heat pump is in defrost mode?

When Does A Heat Pump Go Into Defrost Mode? You’ll know the defrost cycle is activated when the heat pump switches from heating to cooling. You may hear the reversing valve when this occurs. Another sign the defrost cycle is running is the indoor unit will run but the outdoor fan will be off.

How long does a unit normally stay in defrost?

Generally, a unit must run for a minimum of about 35 minutes after starting up before completing its first defrost. From there, defrosts should occur no more often than approximately every 40 minutes.