Desert Aire SelectAire Plus SP Series, Installation And Operation Manual

Page: 88 / 110

88
• If a Desert Aire RecoverAire (ER) unit is supplied, the SelectAire Plus will
command the ER unit to flow the appropriate airflow in the ER unit.
5.5.3 Dehumidifier Operation
The SelectAire Plus offers customized dehumidification to the pool space by dedicating a
smaller circuit to sensible heat exchanger and a larger circuit to cover latent heat exchange.
The latent enhanced circuit includes a 100% passive wrap around heat pipe assembly. In the
latent circuit the heat-pipe wraps around the DX evaporator. Connecting refrigerant piping in
or out of the heat-pipe is not required so is a completely isolated system. It offers “free”
pre-evaporator cooling and post evaporator heating without the use of expensive electrical
resources. The heat pipe pre-cools and post-heats the airstream to allow the evaporator to
maximize the moisture removal content. This allows for the most efficient means of removing
moisture from the air stream.
Dehumidification mode is activated when the intake air has a relatively low sensible load, but
a high latent load. In dehumidification mode the latent circuit (Circuit B) will initiate to meet
the dry bulb temperature and relative humidity setting that is commanded by the CM3560
controller. This is called the first stage of dehumidification. If running Circuit B alone does not
satisfy this relative humidity requirement the second sensible circuit (Circuit A) will come on
line to meet the requirement. This is called the second stage of dehumidification.
5.5.4 Cooling Operation
Cooling mode and stages are enabled as the temperature within the space rises. In cooling
mode, Circuit A is the first stage and Circuit B is the second stage. If equipped with a co-axial
pool water heater, heat is rejected to the pool water if pool heating is required. If the pool
temperature is satisfied, the heat is rejected to a cooling condenser (if equipped).
5.5.5 RecoverAire (ER) Energy Recovery Operation
The SP unit will work in conjunction with a Desert Aire ER unit or similar type energy
recovery unit. Energy recovery is performed in the first stage of heating when the unit is set
to occupied mode. Secondly, Circuit A will start in reheat mode. Air will be directed to the
exhaust airstream after flowing through the evaporator, except for when the second stage of
Dehumidification is active. This recovers energy to the refrigeration circuit that can be used to
heat outdoor air.
5.5.6 Damper Operation
The SP uses strategic damper operation and positioning to maximize airflow efficiency
through the SP cabinet. The dampers function as outlined below.
5.5.6.1 Outdoor Air and Outside Air Bypass Dampers
The Outdoor Air damper will open when there is a call for outdoor air. The Outdoor
Air Bypass Damper will modulate automatically to maintain the outdoor air CFM.
Desert Aire - SP Manual