Wiring Guide
Instruction Sheet
SR501-4 Switching Relay
92
Alternative
Wiring
TACO SR501-4 REPLACEMNENT CROSS-REFERENCE
MANUFACTURER MODEL CONNECTIONS
Taco SR501-4 H N 3 4 NO 4 NC 5 6 NO 6 NC R/T W/T C
Argo AR821 1234 5 6 T
AR822 L1 L2 3 4 NO 4 NC 5 6 NO 6 NC R/T G/T C
Colombus MR10 L1 L2 3 4 NO 4 NC 5 6 NO 6 NC R/T G/T C
Erie SR100 L1 N 3 4 NO 4 NC 5 6 NO 6 NC R/T G/T C
Honeywell RA89A 1234 T T
RA832A 1234 XX T T
R845A 1234 5 6 T T
White-Rogers 889-189 1234 T T
829-845 1234 5 6 T T
Features:
External Indicator Lights
Universal Replaceability
Snap-in PC Board
Simplified Wiring
Sealed Relays
Fuse Protected Outputs
100% Factory Tested
Contractor Friendly PC Board Layout
Universal Thermostat Compatibility
UL Approved
Extended 3 Year Warranty
Made in the USA
Operation:
Connect a thermostat to the “T T” terminals
on the switching relay. When the thermo-
stat calls for heat, the relay is energized and
power is given to the circulator.
Power Input:
Connect 120 volt ac power to terminals N
and H.
Jumper Placement:
The jumper is factory installed between terminals H
and 3 to switch power on terminals 4 n/o and 4 n/c.
External Diagnostics:
The External lights show full functionality of the
switching relay. The green light should always be on,
indicating that power is connected. When the ther-
mostat calls for heat, both the appropriate circulator
and red indicating light is energized.
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 pro-
vides the products to maximize system performance
while simplifying both installation and service.
SR 501-4
NH3 4 4 566
N/O N/ON/C N/CCOM COM
120 VAC
INPUT
TT
COM
R
W
24
VAC
TO: 120 VAC POWER
CIRCULATOR
TO: ZC
THERMOSTAT
TO: ZR
ONE ZONE
SWITCHING RELAY
FUSE
6 AMP
POWER
ZONE 1
LED
INDICATORS
FUSE
6 AMP
ONE ZONE
SWITCHING RELAY
SR 501-4
FUSE
6 AMP
POWER
ZONE 1
LED
INDICATORS
FUSE
6 AMP
NH3 4 4 566
N/O N/ON/C N/CCOM COM
120 VAC
INPUT
TT
COM
R
W
24
VAC
TO: 120 VAC POWER
CIRCULATOR
JUMPER
TO: TT ON
BOILER
THERMOSTAT
Terminal Description:
T & T Thermostat Connection
COM Common side of transformer, to power some
setback thermostats
N Neutral wire of power input
H Hot wire of power input
3 Common terminal for 4 n/o and 4 n/c
4 n/o Normally open terminal
4 n/c Normally closed terminal
6 n/c Normally closed terminal
6 n/o Normally open terminal
5 Common terminal for 6 n/o and 6 n/c
NOTE: When using Alternative Wiring diagram, the boiler operating
control’s ZC terminal will see the load of the circulator(s).
WARNING: When using Alternative Wiring diagram, wiring instruc-
tions 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.
Specifications:
PRODUCT NUMBER INPUT MAXIMUM TYPE 1 ENCLOSURE
NUMBER OF ZONES VOLTAGE COMBINED LOAD WIDTH HEIGHT DEPTH
SR501-4 1 120/60/1 VAC 12 amps 4
7
/8"6
5
/8"2
3
/8"
All circulator relay connections, including ZC/ZR, are rated
1
/3 hp (6 FLA, 36 LRA) at 120 VAC.
The thermostat connection supplies a 24 VAC class 2 output.
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 thermostat connections, and 14-22 gauge wire for
24 VAC source connections.
Typical
Wiring
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 inter-
ference received, including interference that may cause undesired operation.
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., 8450 Lawson Road, Unit #3, Milton, Ontario L9T 0J8. Telephone: 905/564-9422. FAX: 905/564-9436.
Visit our web site at: http://www.taco-hvac.com
Printed in USA
Copyright 2010
TACO, Inc.