Dunkirk EXCELSIOR EXB4075 Installation, Operation & Maintenance Manual page 23

Figure 21 - Piping and Wiring Multi-Zone System With Circulators And Domestic Hot Water Priority
FIGURE 21
HYDROSTAT
MODEL 3250
TO OIL
BURNER
L
120 VAC
N
10 - HYDRONIC PIPING
INDIRECT WATER
HEATER, AQUASTAT
OR THERMOSTAT
ELECTRONIC
FUSE
24AC
30 VA
COMMON
ARM-4P
CONTROL WITH
PRIORITY
23
TANK
CONTROL
T-STAT
THERMOSTATS
DATA PORT
PRIORITY
ZONE 2
ZONE
1 2
T T T
Z
W R W
+
PRIORITY ON
X-X
ZR-ZC
ZONE 1 ZONE 1 ZONE 2 ZONE 2
1 2
X X
L N L
ISOLATED ZC ZR
PRIORITY ZONE 2
SWITCH
CIRC
DHW
CIRC
T-STAT
T-STAT
ZONE 3 ZONE 4
COMMON
3 4
T T T T T
R W R W R
24 VAC
@ 1VA
TO EXTRA
ZONE MODULE
PRIORITY ON
ZONE 3 ZONE 3 ZONE 4 ZONE 4
3 4
L N
N L N L N
ZONE 3 ZONE 4
120 VAC
CIRC
CIRC