Manual 2100-631
Page
50 of 53
FIGURE 19
CIRCUIT DIAGRAMS
34. PRESSURE SERVICE PORTS
High and low pressure service ports are installed on
all units so that the system operating pressures can be
observed.
35. DEHUMIDIFICATION CIRCUIT
The dehumidification circuit incorporates an
independent heat exchanger coil in the supply air
stream. This coil reheats the supply air after it passes
over the cooling coil without requiring the gas burner to
be used for reheat purposes. This results in very high
mechanical dehumidification capability from the air
conditioner on demand without using gas reheat.
The dehumidification refrigerant reheat circuit is
controlled by a three way valve directing the refrigerant
gas to the normal condenser during periods when
standard air conditioning is required. During periods
of time of low ambient temperature (approximately 65°
to 75° outdoor) & high indoor humidity, a humidistat
senses the need for mechanical dehumidification. It
then energizes both the compressor circuit and the three
way valve, thus directing the hot refrigerant discharge
gas into a separate desuperheating condenser circuit,
which reheats the conditioned air before it is delivered
to the room. The refrigerant gas is then routed from the
desuperheating condenser to the system condenser for
further heat transfer. A small orifice inserted between
the reheat coil return line and suction line will prevent
liquid from accumulating in the reheat coil when it is
inactive. This drain does not affect the normal operation
of the system. A check valve is located in the reheat
oil return line. It has a soft spring to hold the ball on
the seat. This will make the method of checking the
ball freedom with a magnet difficult. Refer to Figure
19 for the location of the check valve and drain back
capillary. When the humidistat is satisfied, the system
automatically switches back to normal air conditioning
mode and either continues to operate or turns off based
on the signal from the wall thermostat. The result is
separate humidity control at minimum operating cost.
AIR CONDITIONING MODE
CIRCUIT DIAGRAM
DEHUMIDIFICATION MODE
CIRCUIT DIAGRAM
