Taco SR504-5 User Guide

102-571

Instruction Sheet

SR502/503/504/506-5 Switching Relay

SUPERSEDES: 10/24/24 EFFECTIVE: 12/11/24

Plant ID No. 9300-4099

OVERVIEW:

The “SR50X-5” refers to a model number where “X” represents the number of control zones. Model number “SR506-5” is used for reference in this document. The SR506-5 is a six zone switching relay that can have up to 6 thermostats connected and will operate up to 6 zone circulators, plus 2 auxiliary outputs (AUX) to control circulators in boiler and primary loops, for example.

The SR506-5 has a priority zone option, allowing zone 1 to operate and deactivate zones 2 through 6 during a priority call; this is ideal when using an indirect water heater.

The SR506-5 includes timing options for Post Purge, Pump Exercise and Priority Protection. The SR506-R-5 also includes an energy saving program that can adjust the temperature of a modulatingcondensing boiler or conventional On/ Off boiler to increase the comfort level and use less fuel, without the need to install an outdoor sensor. It also supports Outdoor Reset (Weather Compensation) when outdoor sensor is connected (or separately purchased Plug-In Reset Control for standard SR506-5 model).

TABLE OF CONTENTS

1. Warnings & Safety Information

2. Location & Installation

3. Operation & DIP Switch Settings

4. Wiring Procedure

5. Product & Application Diagrams

6. Reset Control Setup & Wiring

For information on Taco’s Switching Relays (SR) including catalog, instruction sheets, submittal data sheets, and our highly praised Zone Controls Wiring Guide, scan the QR code below or visit www.TacoComfort.com.

7. Troubleshooting & FAQs

8. Fuse Replacement

9. Specications

10. Accessories & Replacement Parts

11. Warranty

1

1. WARNINGS & SAFETY INFORMATION:

FCC Regulatory Statements

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.

(2) This device must accept any interference received, including interference that may cause undesired operation.

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the Federal Communication Commission (FCC) rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment causes harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by doing one or more of the following measures:

• Reorient or relocate the receiving antenna.

• Increase the separation between the equipment and receiver.

• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.

• Consult the dealer or an experienced radio/TV technician for help.

NOTE: THE GRANTEE IS NOT RESPONSIBLE FOR ANY CHANGES OR MODIFICATIONS NOT EXPRESSLY APPROVED BY THE PARTY RESPONSIBLE FOR COMPLIANCE. SUCH MODIFICATIONS COULD VOID THE USER’S AUTHORITY TO OPERATE THE EQUIPMENT.

RF Exposure Warning

This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment. In order to avoid the possibility of exceeding the FCC radio frequency exposure limits, human proximity to the antenna shall not be less than 20 cm during normal operation and must not be co-located or operating in conjunction with any other antenna or transmitter.

ISED Regulatory Statements

This device complies with ISED Canada license-exempt RSS standard(s). Operation is subject to the following two conditions: (1) this device may not cause interference, and (2) this device must accept any interference, including interference that may cause undesired operation of the device.

Le présent appareil est conforme avec ISED Canada applicables aux appareils radio exempts de licence. L’exploitation est autorisée aux deux conditions suivantes: (1) l’appareil ne doit pas produire de brouillage, et (2) l’utilisateur de l’appareil doit accepter tout brouillage radioélectrique subi, même si le brouillage est susceptible d’en compromettre le fonctionnement.

CAN ICES-3 (B)/NMB-3(B)

RF Exposure Information

This equipment complies with ISED RSS-102 radiation exposure limits set forth for an uncontrolled environment. This transmitter must be installed to provide a separation distance of at least 20 cm from all persons and must not be co-located or operating in conjunction with any other antenna or transmitter.

Cet équipement est conforme avec ISED RSS-102 des limites d’exposition aux rayonnements dénies pour un environnement non

contrôlé. Cet émetteur doit être installé à au moins 20 cm de toute personne et ne doit pas être colocalisé ou fonctionner en association avec une autre antenne ou émetteur.

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 90°C. Failure to follow these instructions 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. All 24 VAC eld wiring terminations require

SELV/Class 2 rated wire.

WARNING: Spare fuses consist of different amp ratings (1) 1AMP and (1) 6AMP. Be sure to replace a blown fuse with the correct fuse rating.

2

2. LOCATION & INSTALLATION:

Planning:

Included in Package:

SR506-5 switching relay; 6 zone

Quick Start Guide

2 Spare fuses attached to inner cover

Tools & Materials Needed:

Small straight blade screwdriver

Phillips screwdriver

Torpedo level

Wire strippers

Location: Do not mount to a surface that exceeds 104°F (40°C). For indoor use only. The unit must be located in dry interior locations. Use only copper conductor supply wire suitable for at least 90°C. All circuits must have a common disconnect and be connected to the same pole of the disconnect. Product is not suitable for installation in hazardous locations.

Installation:

1. Hang the panel on a wall with one mounting screw. 2. Level the panel.

SR506-R-5 switching relay also includes: Strap-on temperature sensor

Screws or hardware for mounting

Electrical connectors for eld wiring

Low and live voltage wiring (per code)

3. Install other 3 mounting screws.

3

3. OPERATION & DIP SWITCH SETTINGS:

General Operation: When any thermostat calls for heat, the appropriate circulating pump is

energized, the red light goes on and the boiler end switch relay and AUX circulator relay(s) are energized (subject to DIP switch settings).

Expansion Connections (Modbus): Set DIP switch (#1) to MASTER on the switching relay that is designated as the priority zone control. Set all other daisy chained zone controls to EXPANSION. Using thermostat wire (18-22 gauge) connect between terminals A, B, GND on the master control to the corresponding A, B, GND on the expansion zone control(s). Zone controls may be daisy chained up to 20 Taco zoning panels using any combination of SR and ZVC controls (120 zones if all are 6 zone panels).

Modbus is an open protocol method used for transmitting information back and forth over serial lines between Zone Control equipment. This will allow for future expansion to the zone control portfolio and with other participating OEM’s equipment.

Priority Operation: When the priority DIP switch (#2) is set to ON and the priority zone (zone 1) is actuated, all other zones will stop

operation until priority zone is satised. When not switched to priority, all zones will operate independently. More adjustments are available

when using the Taco Control mobile app.

Priority Protection Operation: If the priority zone calls continuously for more than one hour, power is returned to all the other zones,

allowing each zone to function independently. Once the priority zone is satised, 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.

Primary Pump Operation: When the DIP switch (#3) is set to OFF, the primary circulating pump output will energize when any zone calls for heat, except the priority zone. When the DIP switch is set to ON, the primary circulating pump output will energize when any zone calls for heat.

Post Purge Operation: When the DIP switch (#4) is set to ON, the last zone on will stay energized for 2 minutes after its thermostat or

aquastat is satised, but not operate the boiler. More adjustments are available when using the Taco Control mobile app. Note: Post purge

is only supported on controls designated as MASTER. Post purge is not supported on expansion controls.

Pump Exercise Operation: When the DIP switch (#5) is set to ON, the solid state timer cycles all the circulating pumps that are attached to the Switching Relay to run for 30 seconds every 2 weeks. More adjustments are available when using the Taco Control mobile app. When using multiple Switching Relays, only the master control DIP switch (#5) should be set to on.

Low Limit (ZC) Operation: When the DIP switch (#6) 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.

AUX PUMP 1; ZR / DHW Recirc Output: The AUX PUMP 1 output is energized when any zone calls for heat. When a DHW supply sensor is connected to Sensor Input terminals, then AUX PUMP 1 will energize a DHW recirculation pump using SmartPlus

®

logic. More

adjustments are available when using the Taco Control mobile app.

AUX PUMP 2; Primary Circulator Output: The AUX PUMP 2 output follows DIP switch setting #3 listed above. More adjustments are available when using the Taco Control mobile app.

SmartPlus Recirc Logic: SmartPlus adds intelligence to your system by learning when hot water is used in the home. The pipe-mounted sensor records daily hot water usage patterns during the course of the week. Recorded data is used to automatically run the circulator at the same times the following week. So hot water is always available when it is needed. If usage pattern changes, the SmartPlus adjusts automatically.

“Smart” Mode (default mode): The SmartPlus logic will run in Pulse mode as described below for the rst 7 days of operation. During the rst 7 days, the SmartPlus logic monitors and records the home’s hot water usage pattern. For the following 7 days, the SmartPlus

logic will use the preceding week’s usage pattern to cycle the pump during the recorded hot water usage times. This process of recording and repeating is continuous, and automatically adjusts the pump’s “ON” times to match the household’s usage pattern.

“Pulse” Mode: When set to Pulse mode, the SmartPlus logic will cycle the circulator pump “ON” for 5 minutes, then “OFF” for 10 minutes to maintain hot water at all faucets and taps. It will repeat the cycle continuously. More adjustments are available when using the Taco Control mobile app.

When a DHW supply sensor is connected to the Sensor Input terminals, AUX PUMP 1 output will now be designated for recirculation of DHW loop and activated in “Smart” mode based on DHW usage.

4

4. WIRING PROCEDURE:

End Switches (Low Voltage Dry Contacts):

Main - The main end switch closes when any zone thermostat calls for heat and connects to T-T on boiler operating

control.

Priority - The priority end switch closes only when the priority zone thermostat or aquastat is calling for heat and connects to DHW T-T on boiler (optional).

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). Note: Some “Power Stealing” style thermostats may require a resistor between the

W & C terminals; a 1000 Ohms 1/2 watt (or larger) have proved to work.

Expansion Connections (24 VAC):

A Connect A on Master zone control to A on all Expansion zone control(s). B Connect B on Master zone control to B on all Expansion zone control(s). G Connect GND on Master zone control to GND on all Expansion zone control(s). 24V Future use; no connection required.

Power Input (120 VAC):

H Connect to 120 VAC Hot side of power supply to zone control. N Connect to 120 VAC Neutral side of power supply to zone control. G Connect ground wire to ground screws on base of zone control.

Low Limit Aquastat / Tankless Coil Application (120 VAC):

ZR - H Connect the Hot (AUX PUMP 1) output to ZR input on boiler’s operating control.

ZR - N Neutral (optional).

ZC - H Connect the ZC (Hot) input to ZC (Hot) output on boiler’s operating control.

ZC - N Connect (optional).

AUX PUMP 1; ZR /DHW Recirc Output (120 VAC):

H Connect the Hot output to Hot power input on circulator. N Connect the Neutral output to Neutral power input on circulator. G Connect ground wire to ground screws on base of zone control.

AUX PUMP 2; Primary Circulator Output (120 VAC):

H Connect the Hot output to Hot power input on circulator. N Connect the Neutral output to Neutral power input on circulator. G Connect ground wire to ground screws on base of zone control.

5

DHW Recirculation using SmartPlus Logic

SmartPlus Recirc Logic Sensor

• Mount the strap-on sensor on domestic hot water supply pipe on water heater using wire tie or pipe clamp and insulate sensor with pipe insulation.

• The sensor must be strapped to metal piping. A short piece of copper or brass tube should be added into non metallic systems for sensor attachment. For best performance, the strap on sensor should be installed a minimum of 6 feet away

from the DHW output but before the rst xture.

• Connect the strap-on sensor to the two terminals labeled Sensor Input Terminal on switching relay.

SmartPlus Recirc Pump Power

• Wire Hot and Neutral from Recirc Pump to Hot and Neutral of AUX PUMP 1 output.

Dedicated Return Line Piping Diagram

Dedicated

Return Line

Cold Water

out to

Fixtures

Check

Valve

Potable Exp. Tank

(valve if permitted by local code)

Pressure

Isolation

Valve

Hose

Bibb

Gauge

P GP G

P G

Union

P.R.V.

B.F.P.

Strainer

Union

Isolation

Valve

Incoming

Cold Water

Switching Relay with

SmartPlus Logic

Kitchen

Laundry

Lav

Tub Shower

Lav

DIP SWITCH SETTINGS

Temp

Sensor

ASSE 1070 /

1017 Dual

Listed Mixing

Valve

NSF 61 w/ Integral checks & Temp Gauge

12" Thermal

Trap

Recommended

T GT G

T G

Water

Heater

Dedicated

Return Line

Hot-Link

®

Switching Relay with SmartPlus Logic

Isolation Valves, Unions and

Hose Bibbs as depicted

Valve or Crossover Style Valve Piping Diagram

Kitchen

Laundry

Lav

Tub Shower

Temp

Sensor

DIP SWITCH SETTINGS

Hot-Link bypass

valve w/ check

Farthest Sink/Lav away on

this particular branch system,

multiple valves may be

required

T GT G

ASSE 1070 /

1017 Dual

Listed Mixing

Valve

NSF 61 w/ Integral checks & Temp Gauge

12" Thermal

Trap

Recommended

Water

Heater

Check

Valve

Cold Water

out to

Fixtures

Potable Exp. Tank

(valve if permitted by local code)

Pressure

Gauge

Isolation

Valve

Hose

Bibb

P GP G

P G

Union

P.R.V.

B.F.P.

Strainer

Union

Isolation

Valve

Incoming

Cold Water

Conceptual Sketches Only, refer to individual manufacturer’s installation instructions for additional details. Local codes shall prevail.

6

5. PRODUCT & APPLICATIONS DIAGRAMS:

PA01C – SR506-5 with 5 Zone Circulators & Indirect DHW; Supply & Return Headers

Mechanical Diagram

C-ZV

P GP G

Electrical Diagram

HEAT

See

Note 1

See

Note 2

DIP Switch Settings

1. OFF - Master

2. ON - Priority

3. OFF - Primary Pump

4. OFF or ON - Post Purge

5. OFF or ON - Pump Exercise

6. OFF – ZC Low Limit

Note 1: Some “Power Stealing” style thermostats may require a resistor between the W & C terminals; a 1000 Ohms 1/2 watt (or larger) have proved to work. Note 2: Ensure load of zone control, circulator(s) & boiler do not exceed LWCO rating.

Conceptual Sketches Only, refer to individual manufacturer’s installation instructions for additional details. Local codes shall prevail.

7

PA02C - SR506-5 with 5 Zone Circulators & Indirect DHW; Primary/Secondary

>ϭ >Ϯ

ŝƌĐƵŝƚ

ƌĞĂŬĞƌ

&ƵƐĞ

^ĞƌǀŝĐĞ ^ǁŝƚĐŚ

>Žǁ tĂƚĞƌ ƵƚŽĨĨ

ϭϮϬǀĂĐ

>ϭ >Ϯ

ŝƌĐƵŝƚ

&ƵƐĞ

^ĞƌǀŝĐĞ ^ǁŝƚĐŚ

>Žǁ tĂƚĞƌ ƵƚŽĨĨ

ϭϮϬǀĂĐ

>ϭ >Ϯ

ŝƌĐƵŝƚ

&ƵƐĞ

^ĞƌǀŝĐĞ ^ǁŝƚĐŚ

>Žǁ tĂƚĞƌ ƵƚŽĨĨ

ϭϮϬǀĂĐ

EŽƚĞϮ

Mechanical Diagram

See

Note 3

Electrical Diagram

See Note 3

See

Note 1

See

^ĞĞ

Note 2

DIP Switch Settings

1. OFF - Master

2. ON - Priority

3. OFF - Primary Pump

4. OFF or ON - Post Purge

5. OFF or ON - Pump Exercise

6. OFF – ZC Low Limit

Note 1: Some “Power Stealing” style thermostats may require a resistor between the W & C terminals; a 1000 Ohms 1/2 watt (or larger) have proved to work. Note 2: Ensure load of zone control, circulator(s) & boiler do not exceed LWCO rating. Note 3: Follow boiler manufacturer’s recommendations on powering of boiler loop circulator. Some boilers require this circulator to be wired to the boiler operating control.

Conceptual Sketches Only, refer to individual manufacturer’s installation instructions for additional details. Local codes shall prevail.

8

PA03C – High & Low Temperature Zones & Indirect DHW; Primary/Secondary

Electrical Diagram

Aux 1

Zone 4

Aux 2

Main Boiler

Priority Boiler

SR Switching Relay

4 ZONE

SR504-5

DIP Switch Settings - Expansion

1. ON - Expansion

2. OFF - Priority

3. OFF - Primary Pump

4. OFF or ON - Post Purge

5. OFF or ON - Pump Exercise

6. OFF – ZC Low Limit

Priority

Power

Zone 1

Zone 2

Zone 3

DIP SWITCH SETTINGS

DIP Switch Settings - Master

1. OFF - Master

2. ON - Priority

3. OFF - Primary Pump

4. OFF or ON - Post Purge

5. OFF or ON - Pump Exercise

6. OFF – ZC Low Limit

DIP SWITCH SETTINGS

R

R C

C

COMRCOM

COM

Sensor

Outdoor

Supply

Sensor

COM

Conceptual Sketches Only, refer to individual manufacturer’s installation instructions for additional details. Local codes shall prevail.

Note 1: Some “Power Stealing” style thermostats may require a resistor between the W & C terminals; a 1000 Ohms 1/2 watt (or larger) have proved to work.

Note 2: Ensure load of zone control, circulator(s) & boiler do not exceed LWCO rating.

Note 3: Follow boiler manufacturer’s recommendations on powering of boiler loop circulator. Some boilers require this circulator to be wired to the boiler operating control.

BOL SUP OUTBOL SUP OUT

BOL SUP OUT

9

PA04C – Boiler with Tankless Coil; Supply & Return Headers

Mechanical Diagram

P GP G

Electrical Diagram

LEGEND

DIP SWITCH SETTINGSDIP SWITCH SETTINGSDIP SWITCH SETTINGSDIP SWITCH SETTINGSDIP SWITCH SETTINGS

DIP Switch Settings

1. OFF - Master

2. OFF - Priority

3. OFF - Primary Pump

4. OFF or ON - Post Purge

5. OFF or ON - Pump Exercise

6. ON – ZC Low Limit

SAFETY NOTICE - TWO SEPARATE sources of power may be connected to an oil boiler’s aquastat control.

Before servicing an oil red boiler, make sure the service switch is off. Then conrm that a secondary source of power does not exist to the boiler’s aquastat control. Failure to x the problem could result in boiler being activated when zone calls for heat, that could result in serious injury or death.

Note 1: Some “Power Stealing” style thermostats may require a resistor between the W & C terminals; a 1000 Ohms 1/2 watt (or larger) have proved to work. Note 2: Ensure load of zone control, circulator(s) & boiler do not exceed LWCO rating.

Conceptual Sketches Only, refer to individual manufacturer’s installation instructions for additional details. Local codes shall prevail.

10

PA05C – Legacy Zone Controls – SR506-EXP-4 (Master) Connected to SR504-5 (Expansion)

Electrical Diagram

Aux 1

Priority

Power

Zone 1

Zone 2

Zone 3

Zone 4

DIP SWITCH SETTINGS

Aux 2

Main Boiler

Priority Boiler

SR Switching Relay

4 ZONE

SR504-5

120

Power

Zone 1

Zone 2

Zone 3

Zone 4

Zone 5

Zone 1

Zone 2

Zone 3

Zone 4

Zone 5

Zone 1

Zone 2

Zone 3

Zone 4

Zone 5

RELAY

6 ZONE

SWITCHING

SR506-4

R W C

(PRIORITY)

T STAT 4 T STAT 5T STAT 6

T STAT 2 T STAT 3

R W C R W C R W C R W C R W C

T STAT 1

A B C

EXPANSION

END

BOILER

SWITCH

PRIORITY

END

END MAIN

MAIN

SWITCH

BOILER

SR506-4

DIP SWITCH

Power

Controls

VAC

Zone 6

(PRIORITY)

120 VAC

N/C

N H

POWER IN

N H

ZONE 6

N H

ZONE 6

N H

ZONE 5

N H

ZONE 4

ZONE 3

N H N H

ZONE 2

N H

ZONE 1

N H

PRIMARY

120

VAC

ZC ZR

Note 1: Some “Power Stealing” style thermostats may require a resistor between the W & C terminals; a 1000 Ohms 1/2 watt (or larger) have proved to work.

Note 2: Ensure load of zone control, circulator(s) & boiler do not exceed LWCO rating.

Note 3: Follow boiler manufacturer’s recommendations on powering of boiler loop circulator. Some boilers require this circulator to be wired to the boiler operating control.

Conceptual Sketches Only, refer to individual manufacturer’s installation instructions for additional details. Local codes shall prevail.

11

PA06C – Legacy Zone Controls – SR504-5 (Master) Connected to SR506-EXP-4 (Expansion)

Electrical Diagram

VAC

120

VAC

(PRIORITY)

120

N/C

VAC

N H

POWER IN

N H

ZONE 6

N H

ZONE 6

N H

ZONE 5

N H

ZONE 4

ZONE 3

N H N H

ZONE 2

N H

ZONE 1

’

Power

Zone 1

Zone 2

Zone 3

Zone 4

Zone 5

Zone 6

Zone 1

Zone 2

Zone 3

Zone 4

Zone 5

Zone 6

Zone 1

Zone 2

Zone 3

Zone 4

Zone 5

Power

R W C

(PRIORITY)

T STAT 4 T STAT 5T STAT 6

T STAT 2 T STAT 3

R W C R W C R W C R W C R W C

T STAT 1

Zone 6

Zone 1

Zone 2

Zone 3

Zone 4

Zone 5

Zone 6

Zone 1

Zone 2

Zone 3

Zone 4

Zone 5

Zone 6

RELAY

6 ZONE

RELAY

6 ZONE

SWITCHING

SR506-4

DIP SWITCH

A B C

EXPANSION

END

BOILER

SWITCH

PRIORITY

MAIN

DIP SWITCH SETTINGSDIP SWITCH SETTINGSDIP SWITCH SETTINGSDIP SWITCH SETTINGS

Power

Controls

END

SWITCH

BOILER

Aux 1

Power

Zone 1

Priority

Zone 2

Zone 3

Zone 4

Aux 2

Main Boiler

Priority Boiler

SR Switching Relay

4 ZONE

SR504-5

N H

PRIMARY

120

VAC

ZC ZR

12

Note 1: Some “Power Stealing” style thermostats may require a resistor between the W & C terminals; a 1000 Ohms 1/2 watt (or larger) have proved to work.

Note 2: Ensure load of zone control, circulator(s) & boiler do not exceed LWCO rating.

Note 3: Follow boiler manufacturer’s recommendations on powering of boiler loop circulator. Some boilers require this circulator to be wired to the boiler operating control.

Conceptual Sketches Only, refer to individual manufacturer’s installation instructions for additional details. Local codes shall prevail.

PA07C – Legacy Zone Controls – SR504-5 (Master) Connected to SR506-EXP-2 (Expansion)

Electrical Diagram

R W C

R W C R W C R W C R W C R W C

1 2 3 4

Expansion

Power

Zone 1

Zone 2

Zone 3

Zone 4

(PRIORITY)

T STAT 4 T STAT 5T STAT 6

6 ZONE

SR506-2

WITCHING RELAY S

T STAT 2 T STAT 3

T STAT 1

EXPANSION

VAC

Zone 5

Zone 6

N H

120

POWER IN

N H

(PRIORITY)

’

N H

ZONE 5 ZONE 6

N H

ZONE 4

ZONE 3

N H N H

ZONE 2

N H

ZONE 1

120

VAC

ZC ZR

End

X X

Switch

DIP SWITCH SETTINGS

Note 1: Some “Power Stealing” style thermostats may require a resistor between the W & C terminals; a 1000 Ohms 1/2 watt (or larger) have proved to work.

Note 2: Ensure load of zone control, circulator(s) & boiler do not exceed LWCO rating.

Note 3: Follow boiler manufacturer’s recommendations on powering of boiler loop circulator. Some boilers require this circulator to be wired to the boiler operating control.

Conceptual Sketches Only, refer to individual manufacturer’s installation instructions for additional details. Local codes shall prevail.

13

PA07C – Legacy Zone Controls – SR506-EXP-4 (Master) with PC700-2 Boiler Reset Control Connected to SR504-5 (Expansion)

Electrical Diagram

Aux 1

Zone 4

Aux 2

Main Boiler

Priority Boiler

SR Switching Relay

4 ZONE

SR504-5

Priority

Power

Zone 1

Zone 2

Zone 3

DIP SWITCH SETTINGSDIP SWITCH SETTINGSDIP SWITCH SETTINGSDIP SWITCH SETTINGS

120

VAC

Power

Zone 1

Zone 2

Zone 3

Zone 4

Zone 1

Zone 2

Zone 3

Zone 4

Zone 5

Zone 1

Zone 2

Zone 3

Zone 4

Zone 5

6 ZONE

SWITCHING

SR506-4

R W C

(PRIORITY)

T STAT 4T STAT 5T STAT 6

T STAT 2T STAT 3

R W C R W C R W C R W C R W C

T STAT 1

A B C

EXPANSION

END

BOILER

SWITCH

SWITCH PRIORITY

PRIORITY

END

MAIN

SWITCH

BOILER

SR506-4

DIP SWITCH

Power

Controls

VAC

Zone 5

Zone 6

RELAY

N H

POWER IN

N/C

N H

ZONE 6

N H

ZONE 6

(PRIORITY)

N H

ZONE 5

N H

ZONE 4

ZONE 3

N H N H

ZONE 2

N H

ZONE 1

N H

PRIMARY

120

VAC

ZC ZR

14

m

3

Co

t

Ou

power

No

power

l

1 2

No

Boi

Note 1: Some “Power Stealing” style thermostats may require a resistor between the W & C terminals; a 1000 Ohms 1/2 watt (or larger) have proved to work.

Note 2: Ensure load of zone control, circulator(s) & boiler do not exceed LWCO rating.

Conceptual Sketches Only, refer to individual manufacturer’s installation instructions for additional details. Local codes shall prevail.

6. RESET CONTROL SETUP & WIRING (OPTIONAL)

Boiler Reset Types: The SR506-R-5 includes two types of boiler reset control logic: (or separately purchased Plug-In Reset Control

for standard SR506-5 model)

Indoor Reset Control (Load Reset) uses the thermostat cycling information to determine the supply water temperature. Thermostat short cycling often suggests that the supply water temperature is too high, while prolonged cycles typically indicate that the water temperature is too low.

Outdoor Reset Control (Weather Compensation) uses an outdoor sensor to compare it against the reset ratio (congured by installer) to determine the appropriate supply water temperature. Outdoor sensor must be purchased separtately.

General Operation: When any thermostat calls for heat, the appropriate circulator is energized, and the red light goes on. The boiler end switch relay and modulating output will be controlled by the reset algorithm; or, either based on indoor thermostat operation or on outdoor temperature.

Control Setup: The Taco Control mobile app is required to set type of reset control and parameters to operate.

Wiring of Reset Control:

Make all sensor and analog output connections to the small Plug-In Reset Control on SR506-R-5.

Sensor Connections:

Boiler Sensor: A boiler supply sensor is required for either indoor or outdoor reset. Mount the provided strap-on sensor to the supply piping of the boiler, and wire it to the Boiler Sensor terminal block on the zone control.

Outdoor Sensor: An outdoor sensor is required when utilizing the outdoor reset function. Mount the Taco outdoor sensor P# 9300-2052RP on north side of building and wire to Outdoor Sensor terminal block on zone control.

Boiler Connections:

Modulating Output: Most Mod-Con boilers have an input for an external modulating signal (0-10 vdc or 4-20 ma) to control boiler. Connect the modulating output to appropriate input terminals on boiler; noting that the polarity is correct. Some Mod-Con boilers also require a T T call for heat to activate boiler. In this case, wire the Main Boiler End Switch to T T input on boiler.

Dry Contact End Switch: ON/OFF boilers are controlled by the Main Boiler End Switch on zone control. Wire the Main Boiler End Switch to T T input on boiler.

15

7. TROUBLE SHOOTING & FAQs

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). A resistor may be needed in order to have the 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 resistor, a 1000 ohm ½ watt

resistor has proven to work with most.

Problem: No heat in a zone or room of building. Solution: LED diagnostic lights will help nd 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 thermostat wiring for errors.

Trouble Shooting Sensors:

As in any troubleshooting procedure, it is important to isolate a problem as much as possible before proceeding. The blinking error LED

light greatly simplies troubleshooting of the SR50X-R-5. If you suspect a wiring fault, return to section 4 and carefully check all external

wiring and wiring connections.

Sensor Errors:

• If an outdoor sensor fault occurs, the SR50X-R-5 will assume a xed outdoor temperature of 32°F (0°C) and will target the appropriate supply water temperature. The Main Boiler light will blink indicating the outdoor sensor error.

• If a boiler sensor fault occurs, the SR50X-R-5 turns the boiler output off and the Priority Boiler light will blink indicating the boiler supply sensor error.

Testing the Sensors:

Sensor Error Handling

Sensor Shorted Sensor Open Sensor

Boiler Sensor Flash once Main Boiler LED Flash twice Main Boiler LED

Outdoor Sensor Flash once Priority Boiler LED Flash twice Priority Boiler LED

Universal Sensor (Recirc) Flash once AUX PUMP 1 LED Flash twice AUX PUMP 1 LED

A good quality test meter capable of measuring up to 5,000 kΩ (1 k = 1000 Ω) is required to measure the sensor resistance. In addition

to this, the actual temperature must be measured with either a good quality digital thermometer, or, if a thermometer is not available, a second sensor can be placed alongside the one to be tested and the readings compared. First, measure the temperature using the thermometer and then measure the resistance of the sensor at the control. The wires from the sensor must not be connected to the control while the test is performed. Using the chart below, estimate the temperature measured by the sensor. The sensor and thermometer readings should be close. If the test meter reads a very high resistance, there may be a broken wire, a poor wiring connection or a defective sensor. If the resistance is very low, the wiring may be shorted, there may be moisture in the sensor, or the sensor may be defective. To test for a defective sensor, measure the resistance directly at the sensor location.

Temperature Resistance

ºF ºC Ω

-30 -34 234,196

-20 -29 165,180

-10 -23 118,018

0 -18 85,362

10 -12 62,465

20 -7 46,218

Temperature Resistance

ºF ºC Ω

30 -1 34,558

40 4 26,099

50 10 19,900

60 16 15,311

70 21 11,883

80 27 9,299

Temperature Resistance

ºF ºC Ω

90 32 7,334

100 38 5,828

110 43 4,665

120 49 3,760

130 54 3,050

140 60 2,490

Temperature Resistance

ºF ºC Ω

150 66 2,045

160 71 1,689

170 77 1,403

180 82 1,172

190 88 983

200 93 829

8. FUSE REPLACEMENT:

Fuses are replaceable; 2 spare fuses are attached to inside of front cover.

WARNING: Spare fuses consist of different amp ratings (1) 1AMP and (1) 6AMP. Be sure to replace a blown fuse with the correct fuse rating.

16

9. SPECIFICATIONS:

Power and Electrical Ratings:

Power Supply: 120 VAC ±10%, 60Hz, 20A

Zone Pump Output Rating: 120 VAC, 1/6 HP

AUX(s) Pump Output Rating:

120 VAC, 1/6 HP

Boiler End Switch Contact Rating: 24 VAC, 1A

Expansion Terminals: Low voltage, 3-wire polarity-sensitive, digital communications that links other Switching Relays (SR-5), Zone Valve Controls (ZVC-5) and other Modbus equipment.

Electrical Terminals (Line Voltage):

Wire Range: 12–18AWG

Torque Screws: 7.0 lbs-in. Max.

Electrical Terminals (Low Voltage):

Wire Range: 14–22AWG

Torque Screws: 3.5 lbs-in. Max.

Transformer Rating: 20 VA, 24 VAC Class II 40 VA with option of second 20 VA transformer

ZC Input Rating:

120 VAC

Environmental Ratings:

Ambient Temperature Rating:

32°F to 104°F (0°C to 40°C)

Operating Humidity Range (% RH): 5 to 90% RH, noncondensing

Sensor Temperature Rating:

-58°F to 230°F (-50°C to 110°C)

DIP Switch Timing Settings:

Post Purge: 30 seconds; adjustable with Taco Control

mobile app

Pump Exercise: 30 seconds per 2 weeks of space heating inactivity; adjustable with Taco Control mobile app

Thermostat Compatibility: Compatible with most mechanical, battery operated, power-stealing (powerrobbing), hardwired and “Smart” thermostats.

Temperature Sensor: 10K ohm NTC thermistor at

77°F (25°C) ± 0.5°F (±0.3°C), beta=3892. Lead length:

up to 500 ft. (150 m) using 18 AWG or larger wire.

Dimensions (HxWxD): 12.58 x 8.44 x 2.66 in. (31.95 x 21.44 x 6.76 cm) approximate

Weight: 4.83 lb. (2.19 kg)

Approvals: UL, FCC

Boiler Modulating Output Rating:

0-10 VDC Mode; 500 Ω min impedance 4-20 mA Mode; 1k Ω max impedance

(With Plug-In Reset Control)

10. ACCESSORIES & REPLACEMENT PARTS

Item Part Number

Strap-on sensor for boiler reset control or SmartPlus logic 9300-4168RP

Outdoor sensor for outdoor boiler reset and smart pump exercise 9300-2052RP

Circulator output fuses; slow blow, 6 amp, 2AG (5mm X 15mm) SR6A-001RP

Slow blow, 1 amp, 2AG (5mm X 15mm) SR1A-001RP

Transformer; 20 VA at 24 VAC with connectors to plug into board 9300-4164RP

Plug-In Reset Control board and strap-on temperature sensor PC800-5

PC700’s adaptor (Allows PC700, PC702 and PC705 to work with new zone controls) 9300-4166RP

Power Stealing thermostat resistor 1000 OHM, 0.5 Watt SRTR-001RP

17

11. WARRANTY

Taco, Inc. will repair or replace without charge (at the company’s option) any product or part which is proven defective under normal use within three (3) years from the date code.

In order to obtain service under this warranty, it is the responsibility of the purchaser to promptly notify the local Taco stocking distributor or Taco in writing and promptly deliver the subject product or part, delivery prepaid, to the stocking distributor. For assistance on warranty returns, the purchaser may either contact the local Taco stocking distributor or Taco. If the subject product or part contains no defect as covered in this warranty, the purchaser will be billed for parts and labor charges in effect at time of factory examination and repair.

Any Taco product or part not installed or operated in conformity with Taco instructions or which has been subject to misuse,

misapplication, the addition of petroleum-based uids or certain

chemical additives to the systems, or other abuse, will not be covered by this warranty.

If in doubt as to whether a particular substance is suitable for use with a Taco product or part, or for any application restrictions, consult the applicable Taco instruction sheets or contact Taco at [401-942-8000].

Taco reserves the right to provide replacement products and parts which are substantially similar in design and functionally equivalent to the defective product or part. Taco reserves the right to make changes in details of design, construction, or arrangement of

materials of its products without notication.

TACO OFFERS THIS WARRANTY IN LIEU OF ALL OTHER EXPRESS WARRANTIES. ANY WARRANTY IMPLIED BY LAW INCLUDING WARRANTIES OF MERCHANTABILITY OR FITNESS IS IN EFFECT ONLY FOR THE DURATION OF THE EXPRESS WARRANTY SET FORTH IN THE FIRST PARAGRAPH ABOVE.

THE ABOVE WARRANTIES ARE IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR STATUTORY, OR ANY OTHER WARRANTY OBLIGATION ON THE PART OF TACO.

TACO WILL NOT BE LIABLE FOR ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES RESULTING FROM THE USE OF ITS PRODUCTS OR ANY INCIDENTAL COSTS OF REMOVING OR REPLACING DEFECTIVE PRODUCTS.

This warranty gives the purchaser specic rights, and the

purchaser may have other rights which vary from state to state. Some states do not allow limitations on how long an implied warranty lasts or on the exclusion of incidental or consequential damages, so these limitations or exclusions may not apply to you.

18

A Taco Family Company

2024