This switch is located on the stack side of the panel box. When this switch is in the OFF
position, the heater will not function at all.
When this switch is in the PUMP position, the circulating pump will run continuously, circulating
heat transfer fluid through the system. However, the burner will not operate, so no heat can be
applied to the heat transfer fluid.
When this switch is in the BURNER position, the heater is fully operational. The circulating
pump will run continuously and the burner will fire when the temperature controller calls for heat.
This is normal operating position for this switch.
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