90
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
THERMOSTATS
FUSE 1 AMP
24 VAC
POWER
SR 506
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
FUSE 1 AMP
24 VAC
POWER
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
ZONE 2
POWER
ZONE 1
ZONE 3
ZONE 4
ZONE 5
ZONE 6
TO: "ZC" ON AQUASTAT
TO: "ZR" ON AQUASTAT
JUMPER
The Taco Connection:
Combine the reliability of the Taco Zone Valves, Priority Zoning
Circulators, Thermostats, and the “00” family of circulators with the
advanced features of the Taco Zone Controls to achieve total system
integration. No matter the application, Taco now provides the products
to maximize system performance while simplifying both installation
and service.
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 per-
sonal injury or death and/or property damage. 10-18 gauge wire recommended for 120 VAC con-
nections 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
TRANSFORMER
MAXIMUM
DIMENSIONS OF ENCLOSURE
NUMBER
OF ZONES
VOLTAGE
COMBINED LOAD
WIDTH
HEIGHT
DEPTH
SR504
4 with Priority
120 VAC I
n
put
20 a
m
ps
10 1/4
"
6 3/4
"
2 3/4
"
SR506
6 with Priority
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
SR504 & SR506 Switching Relay
Features:
External Indicator Lights
Switchable Priority
Simplified Wiring
Fully Enclosed Snap-Out Relays
Compact Design
Fuse Protected
100% Factory Tested
Isolated End Switch
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 circu-
lator 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 actuated, all other zones will stop operation until zone 6 is sat-
isfied. When zone 6 is not switched to priority, all zones will operate
independently.
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.
Operation:
When any thermostat calls for heat, the boiler and appro-
priate circulator 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 actuated, all other zones will stop operation until zone 6 is sat-
isfied. When zone 6 is not switched to priority, all zones will operate
independently.
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 aquas-
tat 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.
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.
