TZ-4 TOTALZONE® ZONE CONTROL PANEL
68-0259-1 6

Fig. 4. PC8900 with W8900A,C Thermostat wiring.

Heat Pump Thermostats

Select a heat pump thermostat from Table 1. If the thermostat

selected has a separate Y1 and W1 wire, as shown in Fig. 5,

leave the zone O/B thermostat type jumper on the TZ-4

disconnected, and wire as shown in Fig. 5.

If the PC8900/W8900 /Thermostat is used in a heat pump

application, use the W8900A, not the W8900B, and wire as

shown in Fig. 4.

M20508B
W8900A/C IS RECOMMEDED FOR CONVENTIONAL AND HEAT PUMP APPLICATIONS. THE W8900B CANNOT
SWITCH THE PANEL TO EMERGENCY HEAT.
LEAVE O/B JUMPER ON TZ-4 DISCONNECTED.
TZ-4 THERMOSTAT
CONNECTORS
1
2
1
S1
S
T1
T
OUT
OUT
LED
G
Y2
Y1
W1
W2
1
2
3
4
GND
C
R
RH
RC
HUM
HUM
VNT
VNT

W8900A,C

PC8900

CO2
1234
2
24 VAC
120 VAC