Control System D - Seresco NP Series Operation And Maintenance Manual

Control System
The dehumidifier control system is composed of sensors, spread throughout the dehumidifier, Main Control
Board, Operator Panel and other electric components, located in the Main Electric Panel.
Temperature Sensors (Pic. D.2):
a) Temperature sensors (thermistors) are used to monitor
various temperatures (air, water, compressor, etc.);
Combo sensor is used to monitor air temperature and
b)
humidity.
d
c
Pic.D.3

RA Combo Sensor (21) measures temperature and humidity of the pool room air (Return Air) entering the
dehumidifier. It is located at the return air ductwork connection to the dehumidifier.

OA Temperature Sensor (22) measures outdoor air temperature; it's located at the OA filter rack.
o
As an option, the combo sensor (instead of regular thermistor) can be installed at the OA intake to
measure both the temperature and humidity of the outdoor air.

ET (EvapT) Temperature Sensor (23) measures the temperature of air leaving evaporator coil. It's located
directly downstream of the evaporator coil(s) (one sensor per each compressor circuit).

SA temperature sensor (24) measures the temperature of the air leaving the dehumidifier (supplied to the
premise). It must be located downstream of the space heater:
o
SA temperature sensor of dehumidifier, equipped with gas heater, would be composed of four
regular temperature sensors, installed in different points at supply duct connection, averaging
temperature reading.

If the dehumidifier is equipped with the pool heating option, the Pool Water Temperature sensors (Pool In
(25) and Pool Out (26)) measure the entering and leaving pool water temperature. The sensors are located at
respective manifolds.
o
As an option, the pool water heat exchanger piping/manifold may have water flow switch also.

The compressor's discharge line (high pressure side) is equipped with Temperature and Pressure sensors set ‐
Discharge Temperature Sensor, High Pressure Transducer and High Pressure Switch (27) ‐ to protect the
compressor and control its operation. A similar function is performed by Suction Temperature Sensor, Low
Pressure Transducer and Low Pressure Switch (28) located at compressor's suction line (low pressure side).
o
Said safeties/sensors are installed on each compressor.

If dehumidifier is equipped with Heat Recovery option, it could also have Exhaust Air (EA) Temperature
Sensor (29), installed downstream of exhaust‐side located heat recovery glycol coil.
Main Electric Panel, apart from devices listed above (control board, OP, etc.) also contains Voltage Monitor; some
optional control sensors and devices such as an air pressure differential sensor, current sensor(s). It may also be
located in main electrical panel or in the dehumidifier in general.
D – Layout and Components
Compressor operation is monitored with pressure sensors (Pic. D.3):
Pressure Transducers (as main operational control and safety) and
c)
Pressure Switches (fast‐reacting backup safety).
d)
Note. Sensors and safeties approximate location is shown on Pic. D.1B and
D.1C – refer as needed.
D‐
a
4
b
Pic. D.2