Bard WG242DA, Installation Instructions Manual, Page: 49 / 81

Manual 2100-376L
Page 49 of 81
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) and 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
FIGURE 19
CIRCUIT DIAGRAMS
AIR CONDITIONING MODE
CIRCUIT DIAGRAM
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.
DEHUMIDIFICATION MODE
CIRCUIT DIAGRAM
MIS-1200
MIS-1199