92
SIX ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE 6
ON
OFF
PRIORITY
120V RELAY
PLUG-IN CARDS
FUSE 1 AMP
24 VAC
POWER
EXPANSION
CONNECTIONS
SLAVE
MASTER
1234
RESET NORMAL
POWER
CONTROL
INTERFACE
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
THERMOSTATS
SR 506-EXP
ZONE 2
POWER
ZONE 1
ZONE 3
ZONE 4
ZONE 5
ZONE 6
JUMPER
SIX ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
ZONE 6
ON
OFF
PRIORITY
120V RELAY
PLUG-IN CARDS
FUSE 1 AMP
24 VAC
POWER
EXPANSION
CONNECTIONS
SLAVE
MASTER
1234
RESET NORMAL
POWER
CONTROL
INTERFACE
120 VOLT CIRCULATORS
ZC ZR
X X
END
SWITCH
POWER
INPUT
120 VAC INPUT
ZONE1
ZONE2
ZONE3
ZONE4 ZONE5 ZONE6
ZONE1 ZONE2 ZONE3 ZONE4 ZONE5 ZONE6
THERMOSTATS
SR 506-EXP
ZONE 2
POWER
ZONE 1
ZONE 3
ZONE 4
ZONE 5
ZONE 6
TO: "ZC" ON AQUASTAT
TO: "ZR" ON AQUASTAT
JUMPER
External Diagnostics:
Externally visible lights show full functionality of the
switching relay. The green light should always be on, indicating that power is
connected. When the thermostat calls for heat, both the appropriate circulator
and red indicating light is energized.
Warning:
Wiring connections must be made in accordance with all applicable electrical codes and these instructions. Use copper wire only. Failure to follow this instruction can result in personal injury or
death and/or property damage. 10-18 gauge wire recommended for 120 VAC connections with 9 in.lbs. max torque, 12-22 gauge wire for thermostat connections with 9 in.lbs. max torque, and 12-22 gauge wire
for 24 VAC source with 5 in.lbs. max torque.
Cold Start Boiler
Application
Tankless Coil Boiler
Application
Specifications:
PRODUCT
NUMBER
POWER
TRANSFORMER
MAXIMUM
DIMENSIONS OF ENCLOSURE
NUMBER
OF ZONES
PORTS
VOLTAGE
COMBINED LOAD
WIDTH
HEIGHT
DEPTH
SR503-EXP
3 with Priority
3
120 VAC I
n
put
20 a
m
ps
10 1/4
"
6 3/4
"
2 3/4
"
SR504-EXP
4 with Priority
3
120 VAC I
n
put
20 a
m
ps
10 1/4
"
6 3/4
"
2 3/4
"
SR506-EXP
6 with Priority
3
120 VAC I
n
put
20 a
m
ps
11 3/4
"
7 1/2
"
3
"
All Switchi
n
g Relays are relay type DPST, have a ther
m
ostat curre
n
t of .18, a
n
d have a si
n
gle phase
m
otor rati
n
g per zo
n
e of 1/3 hp (7.2A) @ 120 VAC.
Instruction Sheet
SR503-EXP, SR504-EXP & SR506-EXP Switching Relay
Features:
External Indicator
Lights
Plug-In PowerPort Cards
Switchable Priority
Simplified Wiring
Add-On Power Controls
Fully Enclosed Snap-Out
Relays
Compact Design
Fuse Protected
100% Factory Tested
Isolated End Switch
Expandable to 20 Zones
Contractor Friendly PC Board
Layout
Universal Thermostat
Compatibility
UL Approved
24 volt Power Input or Output
Terminal
Extended 3 Year Warranty
Made in the USA
Do it Once. Do it Right.
®
TACO, INC.
, 1160 Cranston Street, Cranston, RI 02920
Telephone: (401) 942-8000
FAX: (401) 942-2360.
TACO (Canada), Ltd.
, 6180 Ordan Drive, Mississauga, Ontario L5T 2B3.
Telephone: 905/564-9422.
FAX: 905/564-9436.
Visit our web site at:
http://www.taco-hvac.com
Printed in USA
Copyright 2005
TACO, Inc.
Operation:
When any thermostat calls for heat, the appropriate circulator is
energized and the isolated end switch (X and X) will start the boiler.
Priority Operation:
When zone 6 is switched to the priority setting and is actu-
ated, all other zones will stop operation until zone 6 is satisfied. When zone 6 is
not switched to priority, all zones will operate independently.
Mode Operation:
When the mode switch is set to NORMAL, the end switch
relay will be energized if any zone is in operation. When the switch is set to
RESET, the end switch relay will only be energized if priority zone is in operation,
or through the operation of a plug-in reset control.
Jumper Placement:
The jumper should be placed between terminals ZC and ZR.
Connect the isolated end switch to the aquastat control on the boiler.
Power Input:
Connect 120 volt ac power input to terminals N and H. Neutral
wire to terminal N. Hot wire to terminal H.
Expansion Connections:
Set the expansion switch to MASTER on the switching
relay that has the designated priority zone or is utilizing the PowerPort options.
Set all other daisy chained controls to SLAVE. Connect thermostat wire (18-22
gauge) between terminals 1, 2, 3, 4 on the master control to the corresponding
1, 2, 3, 4 on the SLAVE control(s). Controls may be daisy chained up to 20 zones
using any combination of -EXP controls.
Operation:
When any thermostat calls for heat, the boiler and appropriate cir-
culator are energized when the boiler temperature is above the set low limit.
Priority Operation:
When zone 6 is switched to the priority setting and is actu-
ated, all other zones will stop operation until zone 6 is satisfied. When zone 6 is
not switched to priority, all zones will operate independently.
Mode Operation:
When the mode switch is set to NORMAL, the end switch
relay will be energized if any zone is in operation. When the switch is set to
RESET, the end switch relay will only be energized if priority zone is in operation,
or through the operation of a plug-in reset control.
Jumper Placement:
MOVE the jumper between terminals ZC and ZR to end
switch X and ZC. Connect terminal ZC to ZC terminal on the aquastat control.
Connect the other end switch X to ZR terminal on the aquastat control. Confirm
polarity is consistent between boiler aquastat and switching relay.
Power Input:
Connect 120 volt ac power input to terminals N and H. Neutral
wire to terminal N. Hot wire to terminal H.
Expansion Connections:
Set the expansion switch to MASTER on the switching
relay that has the designated priority zone or is utilizing the PowerPort options.
Set all other daisy chained controls to SLAVE. Connect thermostat wire (18-22
gauge) between terminals 1, 2, 3, 4 on the master control to the corresponding
1, 2, 3, 4 on the SLAVE control(s). Controls may be daisy chained up to 20 zones
using any combination of -EXP controls.
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 cir-
cumstances, causing injury or death.
