Smith Cast Iron Boilers GT Series manual Electrical Wiring, Thermostat Installation

GT INSTALLATION AND OPERATION INSTRUCTIONS Page 19

ELECTRICAL WIRING

CAUTION: Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation!

The electrical connections to this boiler must be made in accordance with all applicable local codes and the latest revision of the National Electrical Code, ANSI/ NFPA-70. Install a separate 120 volt 15 amp circuit for the boiler, Figures 28 and 29. A properly rated shut- off switch should be located at the boiler. The boiler must be grounded in accordance with the authority having jurisdiction, or if none, the latest revision of the National Electrical Code, ANSI/NFPA-70. Line voltage field wiring of any controls or other devices must conform to the temperature limitation of type T wire at 95°F, 35°C, above room temperature.Use copper conductors with a minimum size of #14 awg. Low voltage wiring must not be less than #18 awg with a neoprene, thermoplastic or other equivalent insulation having a minimum insulation thickness of 0.012 in, 3 mm.

Schematic and ladder diagrams of the boilers wiring are shown in Figures 33 & 34.

CAUTION: The contact capacity of outputs C1 or Ap is 3 amps with a maximum inrush of 6 amps. If the amp draw of the pumps exceeds these maximums, a pump controller, or isolation relay must be used to prevent damage to the boiler. Damage caused by improper wiring will void the warranty!

Before supplying 120 volts to the boiler, do a continuity check between all the wires and the ground to make sure that there are no electrical shorts that could damage the Sentry 2100 board.

Never use magnetic tip screwdriver near the Sentry 2100.

Verify that the wires connected to the Sentry TC and AC terminals are not grounded, or have any voltage applied to them, or voltage to ground - dry contact closure only.

Ensure that the probe wire is not damaged.

CAUTION: Damage to the electrical system components caused by improper wiring will void the warranty!

Thermostat Installation

ALWAYS follow the instructions included with the thermostat to be used to control the boiler. Proper location of the thermostat will ensure efficient trouble-free operation of the boiler. Mount the thermostat to an inside wall at a height approximately five feet above the floor.

Avoid placing the thermostat in areas that will not provide an accurate measurement of the room temperature. Locating the thermostat behind a door, in an alcove, close to a source of thermal radiation or in a drafty area will cause poor or sporadic heating.

Figure 28 - Basic Heating System Wiring