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X Wiring
WARNING
All wiring and grounding must be done in accordance with the authoity having jurisdiction or, in the absence of such
authority, with the National Electric Code (ANSI/NFPA70).
1) 120 Volt Wiring - Provide the boiler with its own 15A branch circuit with fused disconnect. How the 120 volt connections
are made depends upon the type of low water cut-off supplied with the boiler.
For boilers equipped with Hydrolevel CG450 - 120 Volt connections are made inside the CG450:
• Connect Hot (“black”) to terminal #1 in CG450
• Connect Neutral (“white”) to terminal #2 in CG450
• Connect Ground (“green” or bare) to green screw on case of CG450
For boilers equipped with McDonnell & Miller #67 low water cut-offs - 120 Volt connections are made inside the
junction box mounted on the low water cut-off:
• Connect Hot (“black”) to black pigtail in junction box
• Connect Neutral (“white”) to white pigtail in junction box
• Connect Ground (“green” or bare) to green screw in junction box
2) Thermostat Wiring - Follow thermostat manufacturer instructions. To insure proper thermostat operation, avoid installa-
tion in areas of poor air circulation, hot spots (near any heat source or in direct sunlight), or cold spots (outside walls,
walls adjacent to unheated areas, locations subject to drafts). Provide Class II circuit between thermostat and boiler.
Connect thermostat wire leads to terminals “T” and “T” on the burner primary control.
3) Optional Tankless Heater Wiring - Install the L4006A with the 3/4 NPT well in the 3/4 tapping in the center of the coil plate.
Make sure that the sensing bulb of this control is fully bottomed out in the well. Route the wire harness from this control
to the “T” and “T” (thermostat) terminals on the burner primary control so that they are in parallel with the space heating
thermostat.
Indirect Water Heater Wiring
Figure 17 shows field wiring for an indirect water heater. A Honeywell R845A or equivalent DPST relay and transformer is
required. The high limit described in Part VIII must also be supplied by the installer. A call for heat from the indirect water
heater thermostat will energize the relay making both sets of contacts. One set of these contacts then energizes the circulator.
The other set of contacts will make the “T” and “T” contacts on the burner primary control, firing the burner. If the boiler
water temperature exceeds the high limit setting of 180F, the high limit will open the “T” - “T” circuit and the burner will shut
down.
If there is a call for space heat, the heating thermostat will make the “T”-”T” circuit and the boiler will fire without regard to
the status of the indirect water heater. The low water cut-off and pressure limit control will interrupt 120 volt power to the
burner in the event of a low water or excessive pressure condition.
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