Heat Pump Condensate Disposal
Since the outdoor coil is cold during heat pump operation, the
condensate water cannot be deposited on the outdoor coil
as the water would cause frost to form on the coil. This frost
would block the airflow through the coil and greatly reduce the
outdoor air. Rather than allow this problem to occur, heat pump
units must dispose of the condensate in another manner.
Temperature-Activated Drain Valve
The most widely used method of
disposing of heat pump condensate
is with a “Temperature-Activated Drain
Valve.” This is a device mounted in the
base pan of a heat pump unit with a
bellows that expands on temperature
rise and contracts with temperature
drop. A shaft with a rubber plug on the
end is connected to the bellows. When
the outdoor temperature remains
above a certain temperature, the bellows is expanded and
the plug fits tightly into a hole in the bottom, or base pan, of
the unit. When the plug is blocking the hole, as it should be
during cooling operation, the condensate water is contained
in the base pan. At temperatures when heating is required,
the bellows contracts, the rubber plug is retracted from the
hole and the heat pump condensate water is allowed to drain
into the wall case. The valve is fully open at 49°F.
Drain Kits
Although the Zoneline units are designed to dissipate all of
the condensate generated during normal cooling operation,
there may be times when abnormal operating conditions
cause more condensate than the unit can dissipate. Heat
pumps also generate condensate that the unit may not
be designed to dissipate. For these reasons, if condensate
dripping from the wall case is objectionable, an internal or
external drain system should be installed. See pages 5 and
6 for information covering the drain systems and the RAD10
kit available to connect to the wall case.
Internal Condensate Removal (ICR) System
GE has developed an Internal Condensate Removal (ICR)
System for Packaged Terminal Heat Pumps. This system has
been offered as an option on Zoneline Packaged Terminal
Heat Pumps since 1982, and thousands of them are in use.
During heat pump operation the ICR system utilizes a small
pump to lift the water from the base pan and pump it into
a collector tray positioned above the indoor coil. The water
drains from the collector tray and drips onto the warm indoor
coil where it is evaporated into the room atmosphere. If an
excess amount of water is pumped to the indoor side, it is
routed back to the outdoor portion of the base pan.
The ICR system has proven to be an effective means of
minimizing the amount of heat pump condensate dripping
from the unit. However, if the restrictions of a particular
installation will allow absolutely no drippage of condensate
water from the wall case, the installation of an internal or
external drain system is recommended.
Units with ICR may not be installed in seacoast or corrosive
environment applications.