Taco SR501 User manual

TACO ZONE CONTROLS WIRING GUIDE
Pages
Switching Relays – Single Zone Wiring 2 – 2
Switching Relays – Oil Boiler Wiring Safety Notice 2 3– 4
Switching Relays – NON EXP Connected Together with Priority 5 – 11
Switching Relays – EXP Connected Together with Priority 12 – 14
Switching Relays – Multiple Indirect Hot Water Heaters 15 – 16
Switching Relays – EXP Connected To Reset Controls (PC700, 702 & 705) 17 – 28
Zone Valve Controls – NON EXP Connected Together with Priority 29 – 34
Zone Valve Controls – EXP Connected Together with Priority 35 – 38
Zone Valve Controls – Connected To Reset Controls (PC700, 702 & 705) 39 – 46
Hydro Air Fan Controls (HAFC 101 & 201) 47 – 51
Specialty Thermostat and Zone Valve Wiring 52 – 56
Radiant Mixing Block 57 – 58
X-Pump Block 59 – 61
iSeries Mixing Valves 62 – 63
Low Water Cutoffs and Electric Water Feeders 64 – 79
Aquastat Wiring 80 – 86
Instruction Sheets 87 – 97
Standard Terms and Definitions –98
Cross Reference 99 – 100
Do it once.
Do it right.
© Taco Catalog No. 100-9.0 Effective Date: July 1, 2010
Supersedes Date: July 1, 2007

TACO Zone Control Product Information
Switching Relays
Product No. Description
SR501 1 Zone Switching Relay
SR501-845RP 1 Zone Switching Relay Replacement PC Board for
Honeywell R845, RA89A, RA832 or Comparable Relay
SR502 2 Zone Switching Relay with Priority
SR503 3 Zone Switching Relay with Priority
SR504 4 Zone Switching Relay with Priority
SR506 6 Zone Switching Relay with Priority
Switching Relays with PowerPort Options and Expandable to 20 Zones
Product No. Description
SR501-EXP 1 Zone Switching Relay
SR503-EXP 3 Zone Switching Relay with Priority and 3 PowerPorts
SR504-EXP 4 Zone Switching Relay with Priority and 3 PowerPorts
SR506-EXP 6 Zone Switching Relay with Priority and 3 PowerPorts
Zone Valve Controls
Product No. Description
ZVC403 3 Zone Valve Control
ZVC404 4 Zone Valve Control with Priority
ZVC405 5 Zone Valve Control
ZVC406 6 Zone Valve Control with Priority
Zone Valve Controls with PowerPort Options and Expandable to 20 Zones
Product No. Description
ZVC404-EXP 4 Zone Valve Control with Priority and 2 PowerPorts
ZVC406-EXP 6 Zone Valve Control with Priority and 2 PowerPorts
Plug-In PowerPort Cards (For use with all -EXP controls)
Product No. Description
PC600 Post Purge Timer Plug-In Card
PC605 Priority Protection Plug-In Card
PC610 Universal Timer/Pump Exercise Plug-In Card
Add-On Power Controls (For use with all -EXP controls)
Product No. Description
PC700 Boiler Reset Control
PC702 2-Stage Boiler Reset Control
PC705 Variable Speed Pump Injection Mixing Control
Fan Controls
Product No. Description
HAFC101 Hydro Air Fan Control
HAFC201 Hydro Air Fan Control with Optional Time Delays
Do it once.
Do it right.

2
AT
TO: 120 VAC POWER
CIRCULATOR
120 VAC
INPUT
THERMOST
RW
TT
COM
24
VAC
N/O N/C N/C N/O
NH3 44665
TO: ZC
SR501
1 ZONE
SWITCHING RELAY
POWER T STAT
TO: ZR
ALTERNATIVE WIRING
(TANKLESS COIL)
T
SR501 Switching Relay Wiring
AT
TO: 120 VAC
POWER
CIRCULATOR
JUMPER
120 VAC
INPUT
THERMOST
RW
TT
COM
24
VAC
N/O N/C N/C N/O
NH3 44665
TO: TT ON BOILER
SR501
1 ZONE
SWITCHING RELAY
POWER T STAT
TYPICAL WIRING
(COLD START)
T
TO: 120 VAC POWER
CIRCULATOR
RW
TT
COM
24
VAC
N/O N/C N/C N/O
NH3 44665
TO: TT ON BOILER
SR501
1 ZONE
SWITCHING RELAY
POWER * T STAT *
ALTERNATIVE WIRING
(24 VAC POWERED INPUT SIGNAL)
N
H
REMOVE JUMPER. DO NOT CONNECT POWER TO N AND H TERMINALS.
* T STAT LIGHT WILL GO
ON AND OFF WITH 24 VAC SIGNAL. POWER LIGHT WILL ALWAYS BE OFF.
24 VAC SIGNAL
Note: When using Alternative Wiring diagram, the boiler oper- ating control’s ZC terminal will see the load of the circulator(s). Warning: When using Alternative Wiring diagram, wiring instructions must be followed so power originates from the boiler aquastat. Failure to follow these wiring instructions may result in a secondary source of power being connected to the boiler that may activate it under certain circumstances, causing injury or death.

NOTE: No tankless coil priority.
3

(cont.)
NOTE: Tankless coil has priority.
THREE ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
THERMOSTAT
FUSE 1 AMP
24 VAC
POWER
ZONE 1 ZONE 2 ZONE 3
120 VOLT CIRCULATORS
ZC X1
ZONE1 ZONE2 ZONE3
SR 503
ZONE 2
POWER
ZONE 1
ZONE 3
L1 L2 T T
LINE VOLTAGE
OIL BURNER RELAY
CIRCULATOR
ON BOILER
(IF ATTACHED)
B2
C1
B1ZR
HONEYWELL L8124
OR EQUAL
120 VAC INPUT
C2
ZC
THERMOSTAT
L1 L2
(NEUTRAL)(HOT)
CIRCUIT
BREAKER
CUSTOMER
EMERGENCY
SWITCH
THERMAL
FUSE
(FIROMATIC)
SERVICE
SWITCH
LOW
WATER
CUTOFF
NP H X2
ZR
NOTE: The boiler operating control’s ZC terminal will see the load of the circulator(s).
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
THERMOSTATS
ZONE 4
ON
OFF
PRIORITY
120V RELAY
FUSE 1 AMP
24 VAC
POWER
ZONE 1 ZONE 2 ZONE 3 ZONE 4
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
ZONE1 ZONE2 ZONE3 ZONE4 POWER
INPUT
SR 504
ZONE 2
POWER
ZONE 1
ZONE 3
ZONE 4
L1 L2 T T
LINE VOLTAGE
OIL BURNER RELAY
CIRCULATOR
ON BOILER
(IF ATTACHED)
B2
C1
B1ZR
HONEYWELL L8124
OR EQUAL
120 VAC INPUT
C2
ZC
THERMOSTAT
L1 L2
(NEUTRAL)(HOT)
CIRCUIT
BREAKER
CUSTOMER
EMERGENCY
SWITCH
THERMAL
FUSE
(FIROMATIC)
SERVICE
SWITCH
LOW
WATER
CUTOFF
4

5
SR502/503 Switching Relay Controlling Another SR502/503 Switching Relay
SR 503
24 VAC
POWER
FUSE 1 AMP
ZONE1 ZONE2 ZONE3
120 VOLT CIRCULATORS
ZONE1 ZONE2 ZONE3
TO: "TT" ON AQUASTAT CONTROL
JUMPER
N P ZC H X ZR
1
X
2
ZONE 2
POWER
ZONE 1
ZONE 3
THREE ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
TT T
SR 503
ZONE1 ZONE2 ZONE3
24 VAC
POWER
FUSE 1 AMP
120 VOLT
CIRCULATORS
ZONE1 ZONE2 ZONE3
120 VAC POWER
JUMPER
N P ZC H X ZR
1
X
2
THREE ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
T
AT
BOILER
H
N
SLAVE
MASTER
AQUASTAT
ON DHW
HEATER
ZONE 2
POWER
ZONE 1
ZONE 3
DHW
HEATER
CIRCULATOR
PRIORITY ON
VIA JUMPER
PLACEMENT
PRIORITY OFF
VIA JUMPER
PLACEMENT

6
SR502/503 Switching Relay Controlling Another SR504/506 Switching Relay
SIX ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE 6
ON
OFF
PRIORITY
120V RELAY
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
POWER
INPUT
120 VAC INPUT
TO: "TT" ON BOILER
ZONE1 ZONE2 ZONE3 ZONE4 ZONE5 ZONE6
ZONE1 ZONE2 ZONE3 ZONE4 ZONE5 ZONE6
FUSE 1 AMP
24 VAC
POWER
SR 506
ZONE 2
POWER
ZONE 1
ZONE 3
ZONE 4
ZONE 5
ZONE 6
THERMOSTATS
BOILER
H
N
SR 503
ZONE1 ZONE2 ZONE3
24 VAC
POWER
FUSE 1 AMP
120 VOLT
CIRCULATORS
ZONE1 ZONE2 ZONE3
JUMPERS
N P ZC H X ZR
1
X
2
THREE ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
T
AT
MASTER
ZONE 2
POWER
ZONE 1
ZONE 3
SLAVE
T
PRIORITY ON
VIA JUMPER
PLACEMENT
REMOVE
JUMPER
PRIORITY
OFF
AQUASTAT
ON DHW
HEATER

7
Two SR504/506 Switching Relays Connected Together
BOILER
H
N
A
AQUASTAT ON
DHW HEATER
TT T
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE 4
ON
OFF
PRIORITY
120V RELAY
FUSE 1 AMP
24 VAC
POWER
ZONE 1 ZONE 2 ZONE 3 ZONE 4
120 VAC INPUT
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
ZONE1 ZONE2 ZONE3 ZONE4 POWER
INPUT
SR 504
ZONE 2
POWER
ZONE 1
ZONE 3
ZONE 4
JUMPER
TT T
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE 4
ON
OFF
PRIORITY
120V RELAY
FUSE 1 AMP
24 VAC
POWER
ZONE 1 ZONE 2 ZONE 3 ZONE 4
120 VAC INPUT
TO: "TT" ON BOILER
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
ZONE1 ZONE2 ZONE3 ZONE4 POWER
INPUT
SR 504
ZONE 2
POWER
ZONE 1
ZONE 3
ZONE 4
JUMPER
DHW
HEATER
CIRCULATOR
OUTPUT
NOT
USED
PRIORITY
ON
PRIORITY
ON

8
Priority Zoning Circulator Controlling SR504/506 Switching Relay
SIX ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE 6
ON
OFF
PRIORITY
120V RELAY
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
POWER
INPUT
120 VAC INPUT
TO: "TT" ON BOILER
ZONE1 ZONE2 ZONE3 ZONE4 ZONE5 ZONE6
ZONE1 ZONE2 ZONE3 ZONE4 ZONE5 ZONE6
FUSE 1 AMP
24 VAC
POWER
SR 506
ZONE 2
POWER
ZONE 1
ZONE 3
ZONE 4
ZONE 5
ZONE 6
ON
OFF
PRIORITY
POWER IN
120 VAC INPUT
THERMOSTAT BOILER PRIORITY
PRIORITY ZONING CIRCULATOR
PR-IN PR-OUT LIVE NEUT
1234
THERMOSTATS
BOILER
H
N
A
AQUASTAT ON
DHW HEATER
MASTER
SLAVE
PRIORITY
ON
REMOVE
JUMPER
PRIORITY
OFF
T

9
Priority Zoning Circulator Controlling 2 SR504/506 Switching Relays
ZONE 4
ON OFF
PRIORITY
120V RELAY
FUSE 1 AMP
ZONE 1 ZONE 2 ZONE 3 ZONE 4
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
ZONE1 ZONE2 ZONE3 ZONE4 POWER
INPUT
SR 504
ZONE 2 POWER ZONE 1 ZONE 3 ZONE 4
TT T
BOILER
ZONE 4
ON OFF
PRIORITY
120V RELAY
FUSE 1 AMP
24 VAC
POWER
ZONE 1 ZONE 2 ZONE 3 ZONE 4
120 VAC INPUT
TO: "TT" ON BOILER
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
ZONE1 ZONE2 ZONE3 ZONE4 POWER
INPUT
SR 504
ZONE 2 POWER ZONE 1 ZONE 3 ZONE 4
TT T
H
N
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
SLAVE
SLAVE
PRIORITY
OFF
PRIORITY
OFF
T T
24 VAC
POWER
ON
OFF
PRIORITY
POWER IN
THERMOSTAT BOILER
PRIORITY
PRIORITY ZONING CIRCULATOR
PR-IN PR-OUT LIVE NEUT
1234
A
AQUASTAT ON
DHW HEATER
120 VAC INPUT
MASTER
PRIORITY
ON
REMOVE
JUMPER
REMOVE
JUMPER

SR502/503 Switching Relay Controlling 2 SR504/506 Switching Relays
ZONE 4
ON OFF
PRIORITY
120V RELAY
FUSE 1 AMP
ZONE 1 ZONE 2 ZONE 3 ZONE 4
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
ZONE1 ZONE2 ZONE3 ZONE4 POWER
INPUT
SR 504
ZONE 2 POWER ZONE 1 ZONE 3 ZONE 4
TT T
BOILER
ZONE 4
ON OFF
PRIORITY
120V RELAY
FUSE 1 AMP
24 VAC
POWER
ZONE 1 ZONE 2 ZONE 3 ZONE 4
120 VAC INPUT
TO: "TT" ON BOILER
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
ZONE1 ZONE2 ZONE3 ZONE4 POWER
INPUT
SR 504
ZONE 2 POWER ZONE 1 ZONE 3 ZONE 4
TT T
H
N
A
SR 503
ZONE1 ZONE2 ZONE3
24 VAC
POWER
FUSE 1 AMP
ZONE1 ZONE2 ZONE3
JUMPER
N P ZC H X ZR
1
X
2
ZONE 2 POWER ZONE 1
TWO ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
PRIORITY
ON
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
MASTER
SLAVE
SLAVE
PRIORITY
OFF
PRIORITY
OFF
T T
TT
24 VAC
POWER
ZONE 3
REMOVE
JUMPER
REMOVE
JUMPER
AQUASTAT ON
DHW HEATER
10

11
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE 4
ON OFF
PRIORITY
120V RELAY
FUSE 1 AMP
ZONE 1 ZONE 2 ZONE 3 ZONE 4
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
ZONE1 ZONE2 ZONE3 ZONE4 POWER
INPUT
SR 504
ZONE 2 POWER ZONE 1 ZONE 3 ZONE 4
TT T
BOILER
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE 4
ON OFF
PRIORITY
120V RELAY
FUSE 1 AMP
ZONE 1 ZONE 2 ZONE 3 ZONE 4
120 VAC
INPUT
TO: "TT" ON BOILER
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
ZONE1 ZONE2 ZONE3 ZONE4 POWER
INPUT
SR 504
ZONE 2 POWER ZONE 1 ZONE 3 ZONE 4
TT T
H
N
T
DHW
CIRCULATOR
JUMPER
RW
TT
COM
24
VAC
N/O N/C N/C N/O
NH3 44 5
66
SR501
POWER T STAT
120 VAC INPUT
1 ZONE SWITCHING RELAY
AQUASTAT ON
DHW HEATER
A
T
MASTER
SLAVESLAVE
REMOVE
JUMPER
REMOVE
JUMPER
PRIORITY OFF PRIORITY OFF
24 VAC POWER
24 VAC POWER
SR501 Switching Relay Controlling 2 SR504/506 Switching Relays

SR501-EXP Switching Relay Controlling Another SR504/506 Switching Relay
SIX ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE 6
ON
OFF
PRIORITY
120V RELAY
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
POWER
INPUT
120 VAC INPUT
TO: "TT" ON BOILER
ZONE1 ZONE2 ZONE3 ZONE4 ZONE5 ZONE6
ZONE1 ZONE2 ZONE3 ZONE4 ZONE5 ZONE6
FUSE 1 AMP
24 VAC
POWER
SR 506
ZONE 2
POWER
ZONE 1
ZONE 3
ZONE 4
ZONE 5
ZONE 6
THERMOSTATS
BOILER
H
N
MASTER
SLAVE
T
REMOVE
JUMPER
PRIORITY
OFF
DHW CIRCULATOR
POWER
T STAT
TO: "TT" ON BOILER
AQUASTAT ON
DHW HEATER
NZCZRHHH
POWER
INPUT
120VAC
INPUT
120VAC
OUTPUT
CIRC
OUTPUT
PRIORITY
OUTPUT
RESET
POWER
CONTROLS
FUSE
1 AMP
NORMAL
MASTER
SLAVE
END
SWITCH
ZONE
VALVE
THERMOSTATEXPANSION
X
COM T/W
T/R
X1 12243
JUMPER
TO: OPTIONAL ZONE VALVE
OR iSeries MIXING VALVE
MODE
FUSE
5 AMP
SR 501-EXP
A
12

SR501-EXP Switching Relay Controlling a ZVC404/406 Zone Valve Control
24 VAC
ZONE 1 ZONE 2 ZONE 3 ZONE 4 ZONE 5 ZONE 6
MODE
NORMAL RESET
FUSE (7 AMP MAX)
TT TT TT TT TT TT
ZONE 6 PRIORITY
OFF
ON
ZVC 406
1234 1234 1234 12 34 1234
ZONE 1 ZONE 2 ZONE 3 ZONE 4 ZONE 5
2 WIRE ZONE VALVE
(NO END SWITCH)
JUMPER
3 & 4
TACO
3 WIRE ZONE VALVE
1
2
3
MOTOR END
SWITCH
THERMOSTAT THERMOSTAT THERMOSTAT
4 WIRE
ZONE VALVE
(POWER OPEN, SELF CLOSING)
T STAT 1 VALVE 1 T STAT 2 VALVE 2 T STAT 3 VALVE 3 T STAT 4 VALVE 4 T STAT 5 VALVE 5 T STAT 6 VALVE 6 POWER
SIX ZONE ZONE VALVE CONTROL
WITH OPTIONAL PRIORITY
24 VAC
FACTORY
INSTALLED
TRANSFORMER
120 VAC
INPUT
WHITE
BLACK
POWER IN
24 VAC
FACTORY
INSTALLED
TRANSFORMER
120 VAC
INPUT
WHITE
BLACK
N/O COM
ZONE 6 RELAY
END
SWITCH
EXTRA
END
SWITCH
MAIN
N/C
TO BOILER AQUASTAT RELAY
BOILER
H
N
SYSTEM
PUMP
BOILER TURNS ON WHEN ANY ZONE VALVE OPENS.
1234
ZONE 6
PRIORITY
ZONE
JUMPER
3 & 4
SEE NOTE
Note: When a circulator is used on the priority zone instead of a zone valve, jumper 3 and 4 of the priority zone.
TTT
120 VAC
INPUT
DHW
HEATER
CIRCULATOR
POWER T STAT
AQUASTAT ON
DHW HEATER
NZCZRHHH
POWER
INPUT
120VAC
INPUT
120VAC
OUTPUT
CIRC
OUTPUT
PRIORITY
OUTPUT
RESET
POWER
CONTROLS
FUSE
1 AMP
NORMAL
MASTER
SLAVE
END
SWITCH
ZONE
VALVE
THERMOSTATEXPANSION
X
COM
T/WT/R
X1 12243
JUMPER
TO: OPTIONAL ZONE VALVE OR iSeries MIXING VALVE
MODE
FUSE
5 AMP
SR 501-EXP
A
TO BOILER AQUASTAT RELAY
MASTER
SLAVE
SYSTEM PUMP TURNS ON WHEN ANY ZONE VALVE OPENS EXCEPT WHEN THE DHW HEATER (SR501-EXP) CALLS.
13

14
2 Expandable Switching Relays Connected Together
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE 4
ON
OFF
PRIORITY
120V RELAY
FUSE 1 AMP
24 VAC
POWER
24 VAC
POWER
MASTER
PLUG-IN CARDS
RESET NORMAL
SLAVE
POWER
CONTROL
INTERFACE
POWER
CONTROL
INTERFACE
THERMOSTATS
ZONE 1 ZONE 2 ZONE 3 ZONE 4
120 VAC INPUT
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
ZONE1 ZONE2 ZONE3 ZONE4 POWER
INPUT
SR 504-EXP
ZONE 2
POWER
ZONE 1
ZONE 3
ZONE 4
JUMPER
BOILER
SWITCH SETTINGS
Master/Slave: Slave
Reset/Normal: Normal
Priority Zone: Off
120 VAC INPUT
H
N
SWITCH SETTINGS
Master/Slave: Master
Reset/Normal: Normal
Priority Zone: On
1234
EXPANSION
1234
EXPANSION
SR504-EXP
SIX ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE 6
ON
OFF
PRIORITY
120V RELAY
PLUG-IN CARDS
FUSE 1 AMP
SLAVE
MASTER
RESET NORMAL
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
POWER
INPUT
TO: "TT" ON BOILER
ZONE1 ZONE2 ZONE3 ZONE4 ZONE5 ZONE6
ZONE1 ZONE2 ZONE3 ZONE4 ZONE5 ZONE6
SR 506-EXP
ZONE 2
POWER
ZONE 1
ZONE 3
ZONE 4
ZONE 5
ZONE 6
JUMPER
DHW
CIRCULATOR
THERMOSTATS
SLAVE
MASTER
A
AQUASTAT
ON DHW
HEATER
T
T

ZONE 4
ON OFF
PRIORITY
120V RELAY
FUSE 1 AMP
24 VAC POWER
ZONE 1 ZONE 2 ZONE 3 ZONE 4
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
ZONE1 ZONE2 ZONE3 ZONE4 POWER
INPUT
SR 504
ZONE 2 POWER ZONE 1 ZONE 3 ZONE 4
TT T
BOILER
ZONE 4
ON OFF
PRIORITY
120V RELAY
FUSE 1 AMP
24 V AC
POWER
ZONE 1 ZONE 2 ZONE 3 ZONE 4
120 VAC INPUT
TO: "TT" ON BOILER
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
ZONE1 ZONE2 ZONE3 ZONE4 POWER
INPUT
SR 504
ZONE 2 POWER ZONE 1 ZONE 3 ZONE 4
TT T
H
N
A
JUMPER
JUMPER
SR 502
ZONE1 ZONE2 ZONE3
24 VAC
POWER
FUSE 1 AMP
ZONE1 ZONE2 ZONE3
JUMPERS
N P ZC H X ZR
1
X
2
ZONE 2 POWER ZONE 1
TWO ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
A
PRIORITY
OFF
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE
NOT
USED
ZONE
NOT
USED
MASTER
SLAVE SLAVE
PRIORITY
ON
PRIORITY
ON
AQUASTATS ON
DHW HEATERS
15
2 Indirect Water Heaters with Priority Connected to Standard Switching Relays

16
BOILER
120 VAC INPUT
TO: "TT" ON BOILER
H
N
A
SR 502
ZONE1 ZONE2 ZONE3
24 VAC
POWER
FUSE 1 AMP
ZONE1 ZONE2 ZONE3
JUMPERS
N P ZC H X ZR
1
X
2
ZONE 2 POWER ZONE 1
TWO ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
A
PRIORITY
OFF
1234
EXPANSION
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE 4
ON OFF
PRIORITY
120V RELAY
FUSE 1 AMP
24 VAC POWER
MASTER
PLUG-IN CARDS
RESET NORMAL
SLAVE
POWER CONTROL INTERFACE
ZONE 1 ZONE 2 ZONE 3 ZONE 4
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
ZONE1 ZONE2 ZONE3 ZONE4 POWER
INPUT
SR 504-EXP
ZONE 2 POWER ZONE 1 ZONE 3 ZONE 4
JUMPER
SWITCH SETTINGS
Master/Slave: Master Reset/Normal: Normal Priority Zone: On
1234
EXPANSION
SR504-EXP
T
FOUR ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE 4
ON OFF
PRIORITY
120V RELAY
FUSE 1 AMP
24 VAC POWER
MASTER
PLUG-IN CARDS
RESET NORMAL
SLAVE
POWER CONTROL INTERFACE
ZONE 1 ZONE 2 ZONE 3 ZONE 4
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
ZONE1 ZONE2 ZONE3 ZONE4 POWER
INPUT
SR 504-EXP
ZONE 2 POWER ZONE 1 ZONE 3 ZONE 4
JUMPER
SWITCH SETTINGS
Master/Slave: Slave Reset/Normal: Normal Priority Zone: Off
SR504-EXP
T
DHW
CIRCULATORS
AQUASTATS ON
DHW HEATERS
MASTER SLAVE
ZONE
NOT
USED
2 Indirect Water Heaters with Priority Connected to EXP Switching Relays

PC700 Boiler Reset Control Connected to SR501-EXP Switching Relay
ZONE
CONTROL
BOIL
SEN
OUT
SEN
BOILER SENSOR
OUTDOOR
SENSOR
PC700
BOILER
SWITCH SETTINGS
Master/Slave: Master
Reset/Normal: Reset
120 VAC INPUT
SYSTEM
CIRCULATOR
POWER
T STAT
TO: "TT" ON BOILER
THERMOSTAT
NZCZRHHH
POWER
INPUT
120VAC
INPUT
120VAC
OUTPUT
CIRC
OUTPUT
PRIORITY
OUTPUT
RESET
POWER
CONTROLS
FUSE
1 AMP
NORMAL
MASTER
SLAVE
END
SWITCH
ZONE
VALVE
THERMOSTATEXPANSION
X
COM T/WT/R
X1 12243
JUMPER
TO: OPTIONAL ZONE VALVE
OR iSeries MIXING VALVE
MODE
FUSE
5 AMP
SR 501-EXP
H
N
T
17

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
NZCZRHHH
POWER
INPUT
120VAC
INPUT
120VAC
OUTPUT
CIRC
OUTPUT
PRIORITY
OUTPUT
END
SWITCH
RESET
OVERRIDE
THERMOSTATEXPANSION
X
COM T/WT/R
X1 12243
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
THERMOSTATEXPANSION
X
COM T/WT/R
X1 12243
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
NZCZRHHH
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