FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE 4
ON
OFF
PRIORITY
120V RELAY
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
POWER
INPUT
120 VAC
INPUT
ZONE1
ZONE2
ZONE3
ZONE4
ZONE1 ZONE2 ZONE3 ZONE4
FUSE 1 AMP
24 VAC
POWER
SR 504
ZONE 2
POWER
ZONE 1
ZONE 3
ZONE 4
THERMOSTATS
BOILER
H
N
MASTER
EXISTING
ZONE
CONTROL
T
PRIMARY
SYSTEM
CIRCULATOR
(Optional)
POWER
T STAT
TO: "TT" ON BOILER
AQUASTAT ON
DHW HEATER
NZC ZR
HH
H
POWER
INPUT
120VAC
INPUT
120VAC
OUTPUT
CIRC
OUTPUT
PRIORITY
OUTPUT
END
SWITCH
RESET
OVERRIDE
THERMOSTAT
EXPANSION
X
COM
T/W
T/R
X1
1
22
4
3
JUMPER
SR 501-EXP
A
RESET
POWER
CONTROLS
FUSE
1 AMP
NORMAL
MASTER
SLAVE
MODE
FUSE
5 AMP
JUMPER
DHW
HEATER
CIRCULATOR
Note: If Zone Control comes on without a call for heat,
reverse Reset Override input (1 & 2) wires on SR501-EXP.
ZONE
CONTROL
BOIL
SEN
OUT
SEN
BOILER SENSOR
OUTDOOR
SENSOR
PC700
K1-A
K1-B
K2-A
K2-A
K1
K2
18
SR501-EXP and PC700 Boiler Reset Control Connected to an Existing Switching Relay
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE 4
ON
OFF
PRIORITY
120V RELAY
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
POWER
INPUT
120 VAC
INPUT
ZONE1
ZONE2
ZONE3
ZONE4
ZONE1 ZONE2 ZONE3 ZONE4
FUSE 1 AMP
24 VAC
POWER
SR 504
ZONE 2
POWER
ZONE 1
ZONE 3
ZONE 4
THERMOSTATS
BOILER
H
N
MASTER
EXISTING
ZONE
CONTROL
T
POWER
T STAT
TO: "TT" ON BOILER
AQUASTAT ON
DHW HEATER
END
SWITCH
RESET
OVERRIDE
THERMOSTAT
EXPANSION
X
COM
T/W
T/R
X1
1
22
4
3
JUMPER
A
RESET
POWER
CONTROLS
FUSE
1 AMP
NORMAL
MODE
REMOVE
JUMPER
DHW
HEATER
CIRCULATOR
ZONE
CONTROL
BOIL
SEN
OUT
SEN
BOILER SENSOR
OUTDOOR
SENSOR
PC700
SLAVE
NZC ZR
HH
H
POWER
INPUT
120VAC
INPUT
120VAC
OUTPUT
CIRC
OUTPUT
PRIORITY
OUTPUT
SR 501-EXP
MASTER
SLAVE
FUSE
5 AMP
K1-A
K1-B
K2-A
K2-A
K1
K2
Connecting a DHW Heater to an Existing Heating Only Switching Relay
Using an SR501-EXP and PC700 Boiler Reset Control