Taco SR501-EXP-4 Instruction Sheet

SUPERSEDES: March 1, 2013
Plant ID# 9300-2872
Operation: When the thermostat calls for heat, the circulating 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
zone is actuated, all other connected zoning panels will stop operation
until the zone is satisfied. When the priority dip switch is set to OFF
and the zone is actuated, all other connected zoning panels will oper-
ate independently.
Mode Operation: When the mode dip switch is set to NORM L, the end
switch relay will be energized if any zone is in operation. When the mode
dip switch is set to RESET, the end switch relay will only be energized
through the operation of a plug-in reset control or closure of Priority Input.
Primary Pump Operation: When the dip switch is set to OFF, the pri-
mary circulating pump output will not energize when zone calls for
heat. When the dip switch is set to ON, the primary circulating pump
output will energize when zone calls for heat.
Post Purge Operation: When the dip switch is set to ON, the circula-
tion pump 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
the zone (priority) on master zone panel calls for heat continuously for
more than one hour, then power is returned to the space heating zones
allowing all the zones to function independently. Once the zone (pri-
ority) on master zone panel is satisfied, the control's auto-reset is acti-
vated and the zone is again allowed to have priority for up to one hour.
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.
End Switch: The switch closes when the thermostat calls for heat and
the mode switch is set to NORM L. The end switch also closes when
the mode switch is set to RESET and a PC Series boiler reset power con-
trol is calling for heat.
Expansion Connections: Set the expansion switch to M STER 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 SL VE.
Using thermostat wire (18-22 gauge) connect between terminals
C on the master control to the corresponding
control(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).
120 V C Connections (N is Neutral, H is Hot):
Power Input
Connect 120 Volt C power.
Primary
Primary Pump (optional)
N/O Zone
Circulator Zone
N/C Zone Normally closed terminal for the Circulator Zone.
Will deactivate on a thermostat call.
N Connect to pump neutral leads.
Specifications:
PRODUCT NUMBER INPUT
NUMBER OF ZONES VOLT GE
SR501-EXP-4 1 120/60/1 V C
ll circulator relay connections, including ZC/ZR, are rated
The end switch connection is rated 24 V C, 1 amp.
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. 120 V C wiring must have a minimum
temperature rating of 75°C. Failure to follow this instruction can result in person-
al injury or death and/or property damage. 12-18 gauge wire recommended for
120 V C connections, 14-22 gauge wire for thermostat connections, and 14-22
gauge wire for 24 V C source connections.
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 left or go
to our website: http://www.taco-hvac.com.
Instruction Sheet
SR501- XP-4 Switching Relay
, B, C on the SL VE
M XIMUM TYPE 1 ENCLOSURE
COMBINED LO D WIDTH HEIGHT
7 5
12 amps 4 / " 6 / "
8 8
1 hp (6 FL , 36 LR ) at 120 V C.
/
3
Wiring Diagram:
TO: "TT" on Boiler Aquastat
POWER
CONTROLS
SLAVE
PRIORITY ON
RESET
PRIMARY PUMP ON
POST PURGE ON
PRIORITY PROTECT ON
PUMP EXERCISE ON
30 SEC/2 WK
NOTE: Resistor (1KΩ, 1 ⁄ W)
2
may be needed between
W and C terminals.
CIRCULATOR
, B,
Dip Switch Settings:
ZONE PRIORITY ON
PRIMARY PUMP FUNCTION ON
POST PURGE ON
PRIORITY PROTECTION ON
PUMP EXERCISE ON
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).
resistor may be needed in order to have the thermostat work properly.
DEPTH
This resistor should be placed between the W & C (common) termi-
3
2 / "
8
nals of the switching relay. If the thermostat manufacturer does not
supply a resistor, a 1000 ohm ½ watt resistor has proven to work with
most models and is readily available at electronic supply outlets (e.g.
8the 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 on, indicating
that power is connected and the solid-state fuse 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 ther-
mostat wiring for errors.
This device complies with part 15 of the FCC Rules. Operation is subject to the fol-
lowing 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.
EFFECTIVE: December 20, 2013
THERMOSTAT
T
TO: DHW Aquastat if PC700
END RESET
EXPANSION THERMOSTAT
SWITCH OVERRIDE
X X A B C R W C 1 2
24 VOLTS AC ONLY
MASTER
OFF
NORMAL
OFF
OFF
ACCESSORY
OFF PORT
LED
OFF
INDICATORS
4 MIN/24 HOUR
FUSE FUSE
6 AMP 6 AMP
SINGLE ZONE
EXPANDABLE SWITCHING RELAY
SR 501-EXP-4
N/O N/C H N
120 VAC INPUT
PRIMARY
120 VAC
CIRCULATOR OUTPUT
PRIMARY
CIRCULATOR
(OPTIONAL)
SLAVE
RESET
30 SEC/2 WK
102-385
See NOTE
Boiler Reset is installed.
(See Page 2.)
POWER
ZONE 1
H
120 VAC
INPUT
MASTER
OFF
NORMAL
OFF
OFF
OFF
OFF
4 MIN/24 HOUR