My heat pump is making a strange noise AND is steaming (in winter).

When a heat pump operates normally, ice forms on the outdoor coil. To melt the ice, the
heat pump periodically initiates a "defrost cycle." During the defrost cycle, the outdoor fan
shuts off, and the coil warms up to melt the ice. Because the fan is off during the defrost
cycle, the heat pump sounds different than during normal operation.
Towards the end of the cycle, the coil will be warm enough to evaporate the moisture on
the coil, and steam can be seen coming from the top of the unit. The defrost cycle lasts
about five minutes after which the heat pump returns to normal operation and continues
to heat your house.
Why is my heat pump "iced up?"

Some temporary icing is normal, but a significant ice build-up
could indicate a problem with either the defrost timer or defrost
sensor.
Also, if the heat pump is low on refrigerant (from a leak or
improper charging), it will build ice faster during normal
operation, and have less ability to melt the ice during defrost.
This is the first home we've owned with a heat pump. Can you explain heat
pump operation?

A heat pump is very similar to an air conditioner. In the summer, an air conditioner uses its
compressor to circulate refrigerant through copper pipes. The refrigerant absorbs heat from
the home and releases it to the outdoors.
A heat pump has a "reversing valve" that reverses the flow of refrigerant in the winter to
absorb heat from the outdoors and release in inside. The control of the reversing valve
determines whether the heat pump heats or cools your house.
Modern heat pumps produce heat three times more efficiently than a resistance-type
electric heater.
How long should a heat pump last?

The average life span for a heat pump is 12-15 years. This can be extended by proper
indoor-outdoor system matching, proper installation, and regular maintenance.
I've heard that heat pumps produce "cold/drafty" heat. Is this true? Why?

Older heat pumps produce register temperatures of 80 - 90 degrees. While 90 degrees
sounds warm, it actually feels cool when you put your hand over the heat register because
the air is moving quickly. Newer heat pumps (built in the last five years) with variable speed
blowers produce higher temperatures in the 100-115 range. This is very close to the 120
degrees produced by a modern gas furnace.


Watkins Mechanical, Inc.
Heating & Air Conditioning