4
Condensate Disposal Systems
Cooling Condensate
Air conditioners produce condensate water as a result of
lowering the humidity of the area being conditioned. When
the indoor coil temperature is below the dew point, moisture
in the air condenses into water droplets on the coil. This water
drains to a pan located under the indoor coil and is routed
through the barrier, the partition separating the indoor and
outdoor sides of the unit, to the base pan on the outdoor side.
It is then picked up and dispersed against the outdoor coil,
which is hot when the unit is in the air conditioning mode.
The water is evaporated into the atmosphere by contact
with the hot outdoor coil. This evaporation process also helps
lower the temperature of the outdoor coil and improves the
operating efficiency of the unit.
Slinger Ring Systems
Packaged Terminal units employ various means of dispersing
the condensate water against the outdoor coil. One of the most
popular, and most effective, means is by the use of a “slinger
ring.” A “slinger ring” is a ring around the circumference of
the outdoor fan. The design of the unit positions the slinger
ring very close to the bottom of the base pan so water in
the base pan is lifted by the rotating ring. Water picked up
by the slinger ring will be dispersed into the air stream and
deposited on the hot outdoor coil where it evaporates.
All Zoneline Series Packaged Terminal Air Conditioners
and Packaged Terminal Heat Pumps utilize a slinger ring
for cooling condensate disposal.
Certification Test Requirements
ARI (Air Conditioning & Refrigerating Institute) requires that all
certified Packaged Terminal Air Conditioners and Packaged
Terminal Heat Pumps pass a cooling condensate disposal
test. One stipulation of the ARI test is that “the test start with
condensate collection pan brimful.” In order to pass the ARI
Condensate Disposal Test the unit must operate continuously
for four hours without condensed water blowing, dripping,
or running off the unit casing during the test or after the
unit has been turned off. Under extremely high outdoor
humidity conditions or extreme operating conditions, such
as exceptionally high air infiltration (a door or window left
open while the unit is running, for instance) it is possible for
any air conditioner to be unable to dissipate all the cooling
condensate generated.
All Zoneline
®
Series Packaged Terminal Air Conditioners
and Packaged Terminal Heat Pumps meet the condensate
disposal requirements of ARI standards 10-9 and 80-9.
Heat Pump Condensate
During the operation of a unit in the heat pump, or “reverse
cycle,” mode the outdoor coil becomes the cold coil and the
indoor coil becomes the hot coil due to reversing the flow of
the refrigerant. When the temperature of the outdoor coil is
below the dew point, condensation will form on the outdoor
coil just as it does on the indoor coil during cooling operation.
Since the dew point is humidity- as well as temperature-
related, there may be more condensate on days when the
relative humidity is high.
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.
