Seresco CLASSIC NE Series, Operation And Maintenance Manual

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E – Sequence of Operation
OMM.E.S.RS.00
E-
1
June
2018
Sequence of Operation
The dehumidifier’s ventilation system establishes the required airflow through the dehumidifier. The control
system compares air temperature and humidity to their desired values (set points) and proceeds to dehumidify,
cool or heat the recirculating air.
If the dehumidifier is equipped with the pool water heating option, the pool water temperature is compared to its
set point and pool heating is provided if required.
Set Points
The control system is constantly adjusting unit operation to achieve and maintain said parameters within couple
degrees/percent of the set point.
Refer to the dehumidifier’s main label for the design value of control parameters, as well as the following note.
Ventilation.
The main blower runs continuously, establishing required airflow and pulling fresh outdoor air onto the premise
through the minimum outdoor air intake (OA1) damper. The main blower speed is pre-set via adjustable variable
signal.
Dehumidifier, though usually does not have it built-in, can control the external
minimum exhaust fan (EF1), to
directs portion of return air outdoors. Like the main blower, exhaust fan speed is controlled via adjustable (pre-set)
variable signals: the exhaust fan speed may vary depending on scheduled ventilation mode (Occupied, Non-
Occupied and Spectator) or call for Economiser Mode (as part of Air Conditioning and/or Dehumidification
operation).
 Note . Externally installed Exhaust Fan(s) and Outdoor Air damper(s) could be also controlled by the
dehumidifier control system. This applies to both, Minimum and Purge/Additional, fans and dampers.
Air Conditioning, Dehumidification and Pool Heating.
Compressor(s)
Whenever the compressor operates, the evaporator is always dehumidifying and cooling the return air. The heat
removed from the air at the evaporator, as well as the heat from the compressor's action, must be rejected to one
of three heat sinks: room (premise) air, pool water (if applicable) or outdoors. The control system will direct the
heat to where it is needed based on room (air and pool water temperature) conditions:
 If room air is needed to be warmed up – more heat is diverted towards reheat coil;
 If pool water is needed to be warmed up – more heat is diverted towards pool heating coaxial heat exchanger
(if dehumidifier is equipped with this option).

Rest of the heat (if any) is diverted towards outdoors (outdoor condenser, fluid cooler, etc.)
Note:
To ensure the dehumidifier’s most economical operation, we recommend maintaining the following
relationship between pool water and room air temperatures:
Room Air T = Pool Water T + 2˚F