A geothermal furnace is a heat pump that uses water instead of air as a source of heat
gain or loss. Water is pumped through a closed loop of pipes buried in the ground, or pumped
from a well and discharged into another well or into a pond. The condenser and evaporator
coil are enclosed in one cabinet. A backup electric heating element may be installed in
the supply ductwork.
In heating mode, heat is extracted from water as it passes through the condenser, and released
through the evaporator coil.
In air conditioning mode, heat is extracted from the evaporator coil and released into
water through the condenser.
Accessories can include; an air filter, electronic air cleaner , high performance media
filter, and a humidifier. The humidifier can be of the steam generating type, which will
be line voltage powered, so caution must be taken to shut off power before servicing. Sometimes
a condensate pump will be used to dispose of the water produce in the dehumidifying action
of the air conditioning.
If the system is zoned, a zone control panel and motor actuated dampers will be installed
on the unit or in the ductwork.
A filter or strainer may be installed in the supply side of the water feed to keep sediment
out of the pump and condenser if drawn from a well.
Routine maintenance includes replacing the air filter or washing the electronic air cleaner
grids, cleaning the humidifier, and servicing the water filter or strainer. All maintenance
should be done with the system shut down.