Taco SR503

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 Specifications

General

Zones	3
Power Source	24 VAC
Switch Type	SPDT
Voltage	120 VAC
Frequency	60 Hz
Switching Relay	Yes
Input Voltage	120 VAC
Output Voltage	24 VAC
Housing Material	Plastic
Transformer Rating	40 VA
Operating Temperature	0°C to 49°C

Summary

Switching Relay Wiring and Instruction Sheets

SR501 Switching Relay Wiring

Illustrates typical and alternative wiring diagrams for the SR501 switching relay.

SR502503504506 Relay Interconnection Wiring

SR501-EXP and PC700 Boiler Reset Control Wiring Example

Demonstrates integrating PC700 with SR501-EXP.

SR501 Switching Relay Instruction Sheet

Detailed instructions for operation, installation, and features of the SR501 relay.

SR504 & SR506 Switching Relay Instruction Sheet

Detailed instructions for operation, installation, and features of SR504/SR506 relays.

Zone Valve Control Wiring and Instruction Sheets

ZVC403405 with System Pump Wiring

ZVC404406 with DHW Pump Wiring

ZVC404-EXP & ZVC406-EXP Zone Valve Control Instruction Sheet

Detailed instructions for EXP models of ZVC404 and ZVC406 zone valve controls.

Specialized Controls, Components, and Aquastat Wiring

Aquastat Wiring Examples

Technical Reference and Safety

SAFETY NOTICE

Important safety precautions regarding power connections and boiler operation.