General Explanation and Guidance

General Explanation and Guidance
The heat pump is a relatively simple device. It operates exactly
as a Summer Air Conditioning unit when it is on the cooling
cycle. Therefore, all the charts and data for service that apply
to summer air conditioning apply to the heat pump when it is
on the cooling cycle, and most apply on the heating cycle
except that "condenser" becomes "evaporator", "evaporator"
becomes "condenser" and "cooling" becomes "heating".
When the heat pump is on the heating cycle, it is necessary
to redirect the refrigerant flow through the refrigerant circuit
external to the compressor. This is accomplished with a
reversing valve. Thus, the hot discharge vapor from the
compressor is directed to the inside coil (evaporator on the
cooling cycle) where the heat is removed, and the vapor
condenses into liquid. It then goes through a capillary tube,
or expansion valve, to the outside coil (condenser on the
cooling cycle) where the liquid is evaporated, and vapor goes
to the compressor.