Taco SR501-HC-4 Instruction Sheet

SUPERSEDES: March 1, 2013
Plant ID# 9300-2795
Features:
External Indicator Lights
Simplified Wiring
Sealed Relays
100% Factory Tested
Contractor Friendly PC Board
Layout
Universal Thermostat Compatibility
UL pproved
Extended 3 Year Warranty
120 V C pplication:
1 zone switching relay with boiler
enable or 2 zone without boiler
enable.
240 V C pplication:
1 zone switching relay when switch-
ing both of the circulator
hot leads (L1 & L2).
Operation:
Connect a thermostat to the R & W1
and/or W2 terminals on the switching
relay. When the thermostat(s) call for
heat, the relays are energized and
power is given to the circulator(s).
Zone Control Power Input:
Connect 120 volt C power input to terminals N and H.
Neutral wire to terminal N. Hot wire to terminal H.
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 either thermostat calls for heat, both
the appropriate relay and red indicating light are energized.
Terminal Description:
R Hot side of transformer. Connect to R on thermostat.
W1 Switched R signal from thermostat #1. Connect to
W on thermostat.
W2 Switched R signal from thermostat #2. Connect to
W on thermostat.
C Common side of transformer. Connect to COM
on thermostat (optional).
N Neutral wire of power input.
H Hot wire of power input.
X1 Dry contacts for relay 1 (W1).
X1 Dry contacts for relay 1 (W1).
X2 Dry contacts for relay 2 (W2).
X2 Dry contacts for relay 2 (W2).
Specifications:
PRODUCT NUMBER
NUMBER OF ZONES
SR501-HC-4 1 or 2
REL Y R TING: 3 / HP (13.8 FL , 82.8 LR at 120 V C) (6.9 FL , 41.4 LR at 240 V C)
4
The thermostat connection supplies a 24 V C class 2 output.
W RNING: Wiring connections must be made in accordance with all
applicable electrical codes. Use copper wire only. Failure to follow this
instruction can result in personal injury or death and/or property
damage. 12-18 gauge wire recommended for 120/240 V C connec-
tions, 14-22 gauge wire for thermostat connections, and 14-22 gauge
wire for 24 V C source connections.
This device complies with part 15 of the FCC Rules. Operation is subject to the following two con-
ditions: (1) This device may not cause harmful interference, and (2) this device must accept any
interference received, including interference that may cause undesired operation.
Instruction Sheet
SR501-H -4 Switching Relay, High
Typical
Wiring:
24 VAC
THERMOSTAT
SR 501-HC-4
POWER N
INPUT
H
(120 VAC)
INPUT TYPE 1 ENCLOSURE
VOLT GE WIDTH HEIGHT
120/60/1 V C, 90 m 4 7 / " 6 5 /
8
See NOTE 1
24
R W1
W2
VAC
T T T
COM
ONE ZONE HC
LED
SWITCHING RELAY
INDICATORS
POWER
RELAY 1
RELAY 2
120 VAC
RELAY 1 RELAY 2
INPUT
N H
X1 X1 X2 X2
BOILER
CONTROL
120 VAC
CIRCULATOR
NOTE 2: When using lternative Wiring diagram, the boiler operating
control's ZC terminal will see the load of the circulator(s).
W RNING: When using lternative 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.
Troubleshooting:
• Problem: Digital thermostats do not work correctly when
connected to a switching relay.
• Solution: Some thermostats are a "Power Stealing" type which
means they are powered by the switching relay with just 2
wires (R & W).
thermostat work properly. This resistor should be placed
between the W & C (common) terminals of the switching
relay. If the thermostat manufacturer does not supply a resis-
tor, a 1000 ohm ½ watt resistor has proven to work with most
models and is readily available at electronic supply outlets (e.g.
Radio Shack). If the thermostat is battery powered, then check
that the batteries are fresh and installed correctly.
• Problem: No heat in a zone or room of building.
• Solution: LED diagnostic lights will help find a component
that is not working properly. The green LED should always be
DEPTH
on, indicating that power is connected and the solid-state fuse
" 2 3 / "
8 8
is good. When there is a call for heat, the red LED will come
on indicating power to the zone circulator. This indicates the
thermostat is working correctly. If the red LED does not come
on, then check the thermostat and thermostat wiring for
errors.
For information on Taco's Switching Relays (SR)
including catalog sheet, instruction sheets, Visio
stencils and our highly praised Zone Controls
Wiring Guide, scan the QR code to the right or
go to our website: http://www.taco-hvac.com.
urrent
EFFECTIVE: December 20, 2013
lternative
Wiring:
24 VAC
THERMOSTAT
R W1
T T T
NOTE 1: Resistor
1
(1KΩ, ⁄ W)
2 ONE ZONE HC
may be needed
SWITCHING RELAY
between W and C
terminals.
SR 501-HC-4
120 VAC
RELAY 1
INPUT
N H
X1 X1 X2 X2
N
POWER INPUT
(120 VAC)
H
ZR
ZC
resistor may be needed in order to have the
102-418
apacity
See NOTE 1
24
W2
VAC
COM
LED
INDICATORS
POWER
RELAY 1
RELAY 2
RELAY 2
120 VAC
CIRCULATOR