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 310-93 and 380-93.
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 35 and 36 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.
