Dunkirk EXCELSIOR EXB4075 Installation, Operation & Maintenance Manual page 22

Figure 20 - Piping and Wiring Multizone System With Zone Valves And Domestic Hot Water Priority
(With Circulator)
FIGURE 20
HYDROSTAT
MODEL 3250
TO OIL
BURNER
L
120 VAC
N
10 - HYDRONIC PIPING
24VAC FROM
TRANSFORMER
C
24 VAC
R
X X
120VAC TO
TRANSFORMER
L
120 VAC
TO XFRM
N
PRIMARY PRIORITY
120VAC
PUMP PUMP
N L L N L
AZ-4CP
CIRC
DHW
CIRC
22
INDIRECT WATER
HEATER, AQUASTAT
OR THERMOSTAT
TANK
T-STAT
CONTROL
T-STAT
T T T T
TO DPM-2
Z1 Z2
STATUS
PRIORITY ON
PRIMARY PUMP
PRIORITY PUMP
X-X CONTACT
ZR ON
ZC ON
FROM BOILER
N ZR ZC
1 2 3 4 1 2 3 4 1
PRI ZONE 1 ZONE 2
ZONE
VALVE
ZONE
VALVE
ON
ZONE VALVE / PUMP
PRIORITY
ZR-ZC
DPM-2
OPTION SWITCHES
KEY
T-STAT
ON
OFF
T T T T
Z3 Z4
ZONE VALVE / PUMP
PRIORITY
ZR-ZC
DPM-2
OPTION SWITCHES
2 3 4 1 2 3 4
ZONE 3 ZONE 4
ZONE
VALVE