E – Sequence of Operation
OMM.E.P.AA.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. The main blower speed is pre‐set via adjustable variable
signal.
Minimum Exhaust Fan (EF),
if dehumidifier is equipped with such option, directs portion of return air outdoors.
Like main blower, exhaust fan(s) speed is also controlled via adjustable (pre‐set) variable signal, that varies based
on scheduled ventilation mode (Occupied, Non‐Occupied and Spectator) or call for Economiser Mode (as part of
Air Conditioning and/or Dehumidification
operation).
Minimum Outdoor Air (OA)
damper
, if dehumidifier is equipped with such option, opens to introduce fresh
outdoor air into the premise. OA damper could be equipped with ON/OFF (simple fully open – fully closed) or
modulating‐controlled actuator; latter one would be controlled same way as minimum exhaust fan.
Purge (Additional Exhaust) Option.
Along with
Min Exhaust Fan
and
Min Outdoor Air
damper, dehumidifier could have additional set of
exhaust
(purge) fan(s)
(PF) and
purge outdoor air damper
(POA), commonly referred as
Purge
. Purge fan(s) and OA
damper(s) function is to allow for higher exhaust and fresh air amount, up to complete (100%) air changeover
(when all exhaust fans and OA dampers are at their max capacities).
Purge Fan(s)
and
Purge Outdoor Air
damper(s) are controlled in the same fashion as
min exhaust fans
and
min
outdoor air
. Some dehumidifiers may be equipped with additional
Return Air
damper: it closes in event of
complete air changeover, separating return air side of dehumidifier from supply side (refer
to Layout and
Components
chapter, as needed, for respective devices’ location).
Complete air changeover, triggered manually, is known as
Purge Mode
.
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.
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
