Smith Cast Iron Boilers GB250 SERIES manual 12

For vent damper-equipped models, connect thermostat to blue leads (see Figure 2.6).

NOTE: If any of original wire supplied with boiler must be replaced, use similar wire of 105° C rating. Otherwise, insulation may melt or degrade, exposing bare wire.

NOTE: Boiler transformer must not be used to power external accessories (i.e., zone valves, relays, etc.) Otherwise, transformer will be overloaded and burn out.

FIGURE 2.13: WIRING DIAGRAM & OPERATION SEQUENCE FOR BOILERS WITH STANDING PILOT & MCDONNELL-MILLER #67 LOW WATER CUT-OFF (EXCEPT GB250-8 & GB250-9, N.G.)

FIGURE 2.14: WIRING DIAGRAM & OPERATION SEQUENCE FOR BOILERS EQUIPPED WITH STANDING PILOT & MCDONNELL-MILLER #67 LOW WATER CUT-OFF (GB250-8 & GB250-9, N.G.)

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