87
AT
TO: 120 VAC POWER
CIRCULATOR
JUMPER
120 VAC
INPUT
THERMOST
R W
T T
COM
24
VAC
N/O N/C N/C N/O
NH 3 44 6 6 5
TO: TT ON BOILER
SR501
1 ZONE SWITCHING RELAY
POWER
T STAT
TACO SR501 REPLACEMNENT CROSS-REFERENCE
MANUFACTURER
MODEL
CONNECTIONS
Taco
SR501
H
N
3
4 NO 4 NC 5
6 NO
6 NC
R/T
W/T C
Argo
AR821
1
2
3
4
5
6
T
AR822
L1 L2 3
4 NO
4 NC 5
6 NO
6 NC
R/T
G/T
C
Colo
m
bus
MR10
L1 L2 3
4 NO
4 NC 5
6 NO
6 NC
R/T
G/T
C
Erie
SR100
L1 L2 3
4 NO
4 NC 5
6 NO
6 NC
R/T
G/T
C
Ho
n
eywell
RA89A
1
2
3
4
T
T
RA832A
1
2
3
4
X
X
T
T
R845A
1
2
3
4
5
6
T
T
White-Rogers
889-189
1
2
3
4
T
T
829-845
1
2
3
4
5
6
T
T
Typical
Wiring
Alternative
Wiring
AT
TO: 120 VAC POWER
CIRCULATOR
120 VAC
INPUT
THERMOST
R W
T T
COM
24
VAC
N/O N/C N/C N/O
NH 3 44 6 6 5
TO: ZC
SR501
1 ZONE SWITCHING RELAY
POWER
T STAT
TO: ZR
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
Specifications:
PRODUCT
NUMBER
TRANSFORMER
MAXIMUM
DIMENSIONS OF ENCLOSURE
NUMBER
OF ZONES VOLTAGE
COMBINED LOAD
WIDTH
HEIGHT
DEPTH
SR501
1 Zo
n
e
120 VAC I
n
put
7.2 a
m
ps
4 1/4
"
5 1/4
"
2 3/4
"
All Switchi
n
g Relays are relay type DPDT, 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
SR501 Switching Relay
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.
Features:
External Indicator Lights
Universal Replaceability
Snap-in PC Board
Simplified Wiring
Fully Enclosed Snap-Out Relays
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 thermostat 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 integra-
tion. No matter the application, Taco now provides
the products to maximize system performance while
simplifying both installation and service.
Warning:
Wiring connections must be made in accordance with all applicable elec-
trical 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.
Note:
When using Alternative Wiring diagram, the boiler operating con-
trol’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 circum-
stances, causing injury or death.
