Taco SR503-EXP

TACO ZONE CONTROLS WIRING GUIDE
Pages
Switching Relays – Single Zone Wiring 2 – 2
Switching Relays – Oil Boiler Wiring Safety Notice 2 3– 4
Switching Relays – N
ON EXP Connected Together with Priority 5 – 11
Switching Relays – EXP Connected Together with Priority 12 – 14
Switching Relays – Multiple Indirect Hot Water Heaters 15 – 16
Switching Relays – EXP Connected To Reset Controls (PC700, 702 & 705) 17 – 28
Zone Valve Controls – N
ON EXP Connected Together with Priority 29 – 34
Zone Valve Controls – EXP Connected Together with Priority 35 – 38
Zone Valve Controls – Connected To Reset Controls (PC700, 702 & 705) 39 – 46
Hydro Air Fan Controls (HAFC 101 & 201) 47 – 51
Specialty Thermostat and Zone Valve Wiring 52 – 56
Radiant Mixing Block 57 – 58
X-Pump Block 59 – 61
iSeries Mixing Valves 62 – 63
Low Water Cutoffs and Electric Water Feeders 64 – 79
Aquastat Wiring 80 – 86
Instruction Sheets 87 – 97
Standard Terms and Definitions – 98
Cross Reference 99 – 100
Do it once.
Do it right.
© Taco Catalog No. 100-9.0 Effective Date: July 1, 2010
Supersedes Date: July 1, 2007

Taco SR503-EXP Specifications

General

Model	SR503-EXP
Number of Zones	3
Voltage	24V AC
Transformer	40 VA
Priority Zone	Yes
Input Voltage	120V AC
Connection	Screw Terminals
Relay Outputs	3
Function	Zone Control
Operating Temperature	0°C to 40°C
Weight	2 lbs

Summary

Taco Zone Control Product Information

Switching Relays with PowerPort Options

Details switching relays expandable to 20 zones with PowerPort options.

Zone Valve Controls with PowerPort Options

Details zone valve controls expandable to 20 zones with PowerPort options.

Safety Notices

Service Technicians Safety Advice

Advice for technicians on checking power sources and correcting wiring.

Two Power Sources Check Procedure

Steps to check for two power sources and identify potential issues.

Boiler Reset & Fan Control Wiring & Integrations

PC700 Boiler Reset Control Wiring

Wiring diagram for PC700 Boiler Reset Control with SR501-EXP.

PC700 SR501-EXP Integration Wiring

Wiring diagrams for PC700/SR501-EXP with existing controls.

PC702 2-Stage Boiler Reset Control Wiring

Wiring diagram for PC702 2-Stage Boiler Reset Control.

PC705 Pump Injection Control Wiring

Wiring diagram for PC705 Pump Injection Control.

Mixing Valves & Pump Block Wiring

Radiant Mixing Block, Single Zone Wiring

Wiring diagram for a single zone Radiant Mixing Block.

X-Pump Block, Single Zone Wiring

Wiring diagram for a single zone X-Pump Block.

Instruction Sheets for Key Controls

SR501 Switching Relay Instruction Sheet

Details features, operation, power, jumpers, diagnostics, specs, warnings, and cross-reference.

SR501-845 RP Replacement Relay Instruction Sheet

Details features, operation, power, jumpers, diagnostics, specs, warnings, and cross-reference.

SR502 & SR503 Switching Relay Instruction Sheet

Details features, operation, priority, jumpers, power, connections, diagnostics, specs, and warnings.

SR504 & SR506 Switching Relay Instruction Sheet

Covers features, operation, priority, modes, jumpers, power, connections, specs, and warnings.

SR501-EXP Switching Relay Instruction Sheet

Covers features, operation, jumpers, power, expansion, diagnostics, specs, and warnings.

SR503504506-EXP Switching Relay Instruction Sheet

Details features, operation, priority, modes, jumpers, expansion, specs, and warnings.

ZVC403 & ZVC405 Zone Valve Control Instruction Sheet

Covers operation, diagnostics, connections, specs, features, and wiring.

ZVC404 & ZVC406 Zone Valve Control Instruction Sheet

Details operation, priority, modes, connections, specs, features, and wiring.