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ComPak
®
Series - Installation, Operation and Maintenance |
35
ComPak
®
Series IOM
Cold Surface Temperature Sensor (2)
The cold wall temperature sensor is shipped pre-wired and mounted on to the field wiring terminals. This sensor
is used to measure the temperature of the coldest surface in the pool enclosure. The sensor is an aluminum bar
1” long by ¼” square with a clearance hole for a number 8 screw and two 6” wires on one end.
When the temperature of the surface drops to within 5 F of the space air dew point the humidity set point will
be automatically reset downward to help prevent condensation on the cold surface. It should be noted that
resetting the humidity set point will not compensate for lower quality building materials such as single pane
glass or non-thermally broken frames.
The sensor should be mounted on an exterior window or door frame that is not in direct sunlight. In cases where
there are no exterior windows or doors, the sensor should be mounted on the inside surface of an exterior
wall. The sensor must be in contact with the cold surface. Electrical connection should be made with 22 AWG,
copper, two-conductor, shielded, twisted-pair cable. Connect the shield drain wire to ground at the ComPak®
unit end only.
Economizer System (Optional) (3)
An economizer system cools the space with outside air instead of the compressor. The CPCS-PCP provides
a dry contact closure to activate the economizer. The contacts of the CPCS-PCP may be connected directly
to the economizer control circuit provided the circuit is 24 VAC maximum and the current does not exceed
1 amp inductive. The other components of the system must be provided by others. (See figure 4-6 below for
an illustration of a typical economizer system.)
Units equipped with an economizer require relocation of the factory mounted return air sensor. It must be
located in a duct that will always contain air that represents the space temperature and humidity.
The economizer will operate only when space cooling is required and there is no dehumidification requirement.
When the outside air temperature is greater than 50°F and more than 5°F below the space temperature set
point and the space temperature rises above the set point, the compressor is disabled and a dry contact closure
between T2.16 and T2.17 is made to activate the economizer.
When the CPCS-PCP contacts close relay R1 is energized causing the outside and exhaust air dampers (by
others) to open and the return air damper (by others) to close. At the same time relay R2 is energized causing
the exhaust fan to run. If the space temperature continues to rise and exceeds the space temperature set point
by more than two degrees, the economizer contact is opened, reversing the damper positions. The compressor
is energized in the space cooling mode (if so equipped). The compressor will then continue to run until the call
for space cooling is satisfied. The economizer will also be activated in the space cooling mode if the auxiliary
air conditioning condenser option is not installed or if the compressor is locked out by a fault condition.
Figure 4-6. Economizer Operation
