Seresco CLASSIC NE-002, Operation And Maintenance Manual

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E – Sequence of Operation
E ‐
2
Compressor Circuit Operation
Piping schematic for compressor circuit is shown on Pic. E.1.
When a demand requires the compressor to operate, the following sequence occurs:
‐ Once blower operation, related safeties and timers are confirmed by the control system, the pump down
solenoid valve opens and once pressure stabilizes, the compressor starts.
‐ Reheat valve diverts portion of hot gas into the reheat coil. Remainder of the hot gas goes into outdoor
condenser (or water ‐ cooled heat exchanger, coupled with fluid cooler or external fluid cooling system) and (if
applicable) pool water heat exchanger.
o
Dehumidifier with pool heating option : pool valve diverts portion of hot gas into pool water heat
exchanger, based on pool water heating demand.
o
Outdoor condenser/fluid cooler fan is engaged only if hot gas is diverted outdoors/to water ‐ cooled
heat exchanger and compressor pressure is higher than pre ‐ set level (see Outdoor Condenser and Fluid
Cooler Operation below).
‐ Once demand for the compressor’s operation is removed (respective call is satisfied), the pump down solenoid
valve closes; once the compressor suction pressure reaches the pre ‐ set pressure, the compressor stops.
Outdoor Condenser and Fluid Cooler Operation.
Based on the type of the outdoor condenser or fluid cooler fans’ type (two ‐ speed fans or EC ‐ type/modulating
fans), respective signal(s) are sent by control system to engage said fan(s): for two ‐ speed fans ‐ on/off signals
(switching speeds, based on compressor head pressure level), for EC ‐ type fans ‐ variable 0 ‐ 10VDC signal
(proportional to the compressor head pressure level). Refer to the fans’ type and wiring diagram if/when needed.
If the fluid cooler is equipped with the built ‐ in pump package (to establish cooling fluid flow between dehumidifier
and the fluid cooler or to serve as additional/booster pump), the said pump is also engaged along with fluid cooler
fans – pump would stay engaged while fans are engaged (regardless of the fans’ speed).
Pic. E.1