Smith Cast Iron Boilers GT Series manual Multiple 4 Wire Zone Valves

Page 20 GT INSTALLATION AND OPERATION INSTRUCTIONS

Figure 29 - Basic Heating System and Indirect Tank Wiring

Multiple 4 Wire Zone Valves

Figure 30 shows the basic multiple zoned system uses normally closed four (4) wire zone valves. This wiring system is used with the piping shown in Figure 26.

When there is a call for heat the room thermostat closes the circuit to the zone valve motor, thus opening the zone valve. When the zone valve is opened, the end switch closes the circuit between terminals T and C on the Sentry 2100 control. The Sentry 2100 provides power to the primary and secondary pumps via terminal C1. Once these pumps are on, the burner fires.

Once the room thermostat is satisfi ed, it breaks power to the zone valve motor. The end switch opens the circuit between terminals T and C shutting down the pumps and the burner.

Multiple Zones w/ Taco Valve Controller Models ZVC403 to ZVC 406

Figure 31 shows the basic multiple zoned system using normally closed 2, 3 or 4 wire Taco zone valves. This wiring system is used with the piping as shown in Figure 26.

When there is a call for heat the room thermostat closes the circuit between the TT terminals on the Taco zone controller. The controller energizes the appropriate zone valve and closes the circuit between terminals T and C on the Sentry 2100 control.The Sentry 2100 provides power to the primary and secondary pumps via terminal C1.

Once these pumps are on, the burner fires.

Once the room thermostat is satisfi ed, it breaks power to the zone valve motor. The end switch opens the circuit between terminals T and C shutting down the pumps and the burner.