Wiring Guide

101
Instruction Sheet
SR503-EXP, SR504-EXP & SR506-EXP Switching Relay
Do it Once. Do it Right.
®
TACO, INC., 1160 Cranston Street, Cranston, RI 02920 Telephone: [phone] FAX: [phone].
TACO (Canada), Ltd., 8450 Lawson Road, Unit #3, Milton, Ontario L9T 0J8. Telephone: [phone]. FAX: [phone].
Visit our web site at: http://www.taco-hvac.com
Printed in USA
Copyright 2010
TACO, Inc.
120 VAC INPUT
TO: "TT" ON BOILER
PRIMARY CIRCULATOR
(OPTIONAL)
TO: "TT" ON BOILER WITH
DHW "TT" INPUT
SIX ZONE
EXPANDABLE SWITCHING RELAY
POWER
CONTROLS
120 VAC CIRCULATORS
ZC
INPUT
120 VAC
ZONE 1 ZONE 2 ZONE 3 ZONE 4 ZONE 5 ZONE 6
ZONE1 ZONE2 ZONE3 ZONE4 ZONE5
THERMOSTATS
SR 506-EXP-4
FUSE
6 AMP
FUSE
6 AMP
FUSE
6 AMP
FUSE
6 AMP
FUSE
6 AMP
FUSE
6 AMP
FUSE
6 AMP
FUSE
6 AMP
NET
EXPANSIONMAIN PRIORITY
XX
XX
AB
CRW
CRW
CRW
CRW
CRW
CRW
C
12
END SWITCH THERMOSTATS (24 VAC)
PRIORITY
N/C
PRIMARY
120 VAC
ZR
H H N H N H NH NH NH NH NH NH NH
SLAVE
PRIORITY ON
RESET
PRIMARY PUMP ON
POST PURGE ON
PRIORITY PROTECT ON
PUMP EXERCISE ON
30 SEC/2 WK
MASTER
OFF
OFF
OFF
OFF
OFF
NORMAL
LOW LIMIT (ZC) ON OFF
4 MIN/24 HOUR
ZONE6 ZONE6
PRIORITY
ACCESSORY
PORT
ZONE 2
POWER
ZONE 1
ZONE 3
ZONE 4
ZONE 5
ZONE 6
LED
INDICATORS
Operation: When any thermostat calls for heat, the appropriate circu-
lating pump is energized and the isolated end switch (X and X) will
start the boiler.
Priority Operation: When the priority dip switch is set to ON and the
priority zone is actuated, all other zones will stop operation until pri-
ority zone is satisfied. When not switched to priority, all zones will
operate independently.
Mode Operation: When the dip 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 the priority zone
is in operation, or through the operation of a plug-in reset control.
Primary Pump Operation: When the dip switch is set to OFF, the pri-
mary circulating pump output will energize when any zone calls for heat,
except the priority zone. When the dip switch is set to ON, the prima-
ry circulating pump output will energize when any zone calls for heat.
Post Purge Operation: When the dip switch is set to ON, the priority
zone output will stay energized for 2 minutes after its thermostat or
aquastat is satisfied, but not operate the boiler.
Priority Protection Operation: When the dip switch is set to ON, and
if the priority zone calls continuously for more than one hour, power is
returned to all the other zones, allowing each zone to function inde-
pendently. Once the priority zone is satisfied, the control's auto-reset is
activated and the priority zone is again allowed to have priority for up
to one hour starting from when it calls next.
Pump Exercise Operation: When the dip switch is set to ON, the solid
state timer cycles all the circulating pumps that are attached to the
Expandable Switching Relay at the selected time interval. The time
interval can be set for the pumps to run for either 30 seconds every 2
weeks or for 4 minutes every 24 hours.
Low Limit (ZC) Operation: When the dip switch is set to ON and the
boiler drops below the set low limit (terminal ZC connected to boiler),
all zone circulating pumps will stop. When the boiler rises above the set
low limit, the zone circulating pumps are allowed to operate.
End Switches (Dry Contacts): The main end switch closes when any
zone thermostat calls for heat and the mode switch is set to NORMAL.
The main end switch also closes when the mode switch is set to RESET
and a PC Series boiler reset power control is calling for heat. The priori-
ty end switch closes only when the priority zone thermostat or aquastat
is calling for heat.
Expansion Connections: Set the expansion switch to MASTER on the
switching relay that has the designated priority zone or is utilizing the
PC Series plug-in option. Set all other daisy chained controls to SLAVE.
Using thermostat wire (18-22 gauge) connect between terminals A, B, C
on the master control to the corresponding A, B, C on the SLAVE con-
trol(s). Controls may be daisy chained up to 20 zoning panels using any
combination of -EXP controls (120 zones if all are 6 zone panels).
Thermostat Input (24 vac):
R Hot side of transformer. Connect to R on thermostat.
W Switched R signal from thermostat. Connect to W on thermostat.
C Common side of transformer. Connect to COM on
thermostat (optional).
NET Network terminals 1 & 2 are tied together for wiring convenience
when using communicating style thermostats (optional).
120 VAC Connections (N is Neutral, H is Hot):
Power Input Connect 120 Volt AC power
Primary Primary Pump (optional)
Zone 1-5 Circulator Zones
Priority Zone 6 Priority Zone (if enabled) or Zone 6
N/C Zone 6 Normally closed terminals for the Priority Zone.
WIll deactivate on a Priority Zone call.
Cold Start Boiler
Application
Specifications:
PRODUCT NUMBER INPUT MAXIMUM TYPE 1 ENCLOSURE
NUMBER OF ZONES VOLTAGE COMBINED LOAD WIDTH HEIGHT DEPTH
SR506-EXP-4 6 with Priority 120/60/1 VAC 20 amps 12
1
/4"8" 3"
All circulator relay connections, including ZC/ZR, are rated
1
/3 hp (6 FLA, 36 LRA) at 120 VAC.
End switch connections are rated 24 VAC, 1 amp.
All thermostat connections supply a 24 VAC class 2 output.
For more wiring diagrams, visit www.taco-hvac.com.
WARNING: Wiring connections must be made in accordance with all
applicable electrical codes. Use copper wire only. 120 VAC wiring must have
a minimum temperature rating of 75°C. Failure to follow this instruction
can result in personal injury or death and/or property damage. 12-18 gauge
wire recommended for 120 VAC connections, 14-22 gauge wire for thermo-
stat connections, and 14-22 gauge wire for 24 VAC source connections.
SLAVE
ZONE PRIORITY ON
RESET
PRIMARY PUMP FUNCTION ON
POST PURGE ON
PRIORITY PROTECTION ON
PUMP EXERCISE ON
30 SEC/2 WK
MASTER
OFF
NORMAL
OFF
OFF
OFF
OFF
4 MIN/24 HOUR
LOW LIMIT (ZC) ON OFF
Dip Switch Settings:
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 are energized.
Features:
Front External Indicator Lights
Ideal for Retrofitting
Primary Circulator Output
Simplified Wiring
Plug-In Power Controls
Sealed Relays
Compact Design
Fuse Protected
100% Factory Tested
Two Isolated End Switches
Expandable to 20 Zoning Panels (120
zones if all are 6 zone panels)
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
This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device
must accept any interference received, including interference that may cause undesired operation.