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Application 302P-2
Mechanical
Electrical
The Switching Relay 302P operates two heating zone circulators when the corresponding thermostat calls for heat.
Zone 1 heats a domestic hot water tank. When priority is selected, zone 2 shuts off when zone 1 is heating. The boiler
is fired when there is a call for heat.
DIP Switches
Master
T-stat 1 Priority On
Exercising On
Post Purge On
Mod Boiler - depends on boiler
The 302P includes
internal circuitry
to support power
stealing thermostats.
External resistors are
not required.
Away
C R Rh W
70
FUSE 2
FUSE 7
FUSE 8
FUSE 3
FUSE 4
FUSE 5
FUSE 6
70 80
90
60
50
100
MOD MAX %
MASTER
MEMBER
OFF
OFF
OFF
4-20 mA
T-STAT 1 PRIORITY : 0N
EXERCISING : ON
POST PURGE : ON
MOD BOILER : 0-10V
RESERVED
FUSE 1
120 VAC
POWER
MOD
X X
tN4
POWER
ROOM
RESPONSE
T1
T2
T3
T4
T5
T6
A
DHW
C R W
BOILER
T-STAT 1
T-STAT 2
T-STAT 3
PRIORITY
PUMP 1
PUMP 2
PUMP 3
PUMP 4
PUMP 5
PUMP 6
L
-
+
N
L
N
L
N
L
N
L
N
L
N
L
N
tN4
A C R W
tN4
A C R W
T-STAT 4
tN4
A C R W
T-STAT 5
tN4
A C R W
T-STAT 6
EXPANSION
tN4
A C R W
tN4
A B C D E
+
T-T
DHW
-
B1
A1
T1
P1
L N
P2
Legend
A1 = DHW Tank Aquastat
B1 = Modulating Condensing Boiler
BP = Boiler Pump
P1 = Zone 1 DHW Tank Pump
P2 = Zone 2 Pump
T1 = WiFi Thermostat 561, 562 or 563
B1
P1
P2
A1
BP
302P
