Wiring Pressure Switches (PC5, PC7 and DHL) and R63 Relay
The PC5 pressure switch wires directly to the MT III as shown
below in
Figure
17. PC5 is a normally closed switch that
completes a circuit between DI2 and M. If the switch opens, the
circuit breaks and generates a dirty filter alarm.
The PC7 pressure switch is wired in series with the R63 NO
contact and MT III shown in
closed switch that completes a circuit between DI1 and M. If
the switch opens, the circuit breaks and an Airflow Fault alarm
will occur after three attempts.
Figure 17: PC7 Pressure Switch
Figure 18: R63 Relay
www.DaikinApplied.com
Figure
17. PC7 is a normally
The DHL switch is wired in series with the R63 relay shown in
Figure
18. The R63 relay is energized with 24 VAC from TB2A-
104 as long as the DHL switch is closed. Three sets of NO dry
contacts from the R63 relay are wired to the MT III: DI4 (line
220), DI1 (line 225) and DI2 (line 868) on the VFD.
NOTE: If the unit was selected for constant volume, then no
DHL would be installed.
13
Wiring
IM 1285-4 • MICROTECH III
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