2
Basic Operation
Service on this boiler should be undertaken only by trained and skilled personnel from a
qualified service agency.
Should overheating occur or the gas supply fail to shut off, do not turn off or disconnect the
electrical supply to the pump. Instead, shut off the gas supply at a location external to the
appliance.
Do not use this boiler if any part has been under water. Immediately call a qualified service
agency to inspect the boiler and to replace any part of the control system and any gas control
which has been under water.
A. General. This water boiler is a natural draft appliance and is equipped with controls for proper
operation. All controls must be in proper working order. Contact a qualified service agency to provide
annual maintenance as specified in the Installation, Operation and Maintenance Manual.
B. Control Locations. See Figure 1 for Control and Safety Device Locations.
1a. Limit (Steam Boiler). An electrical device that automatically interrupts the boiler operation when
the steam pressure exceeds the “CUT IN” pressure plus the differential (1 to 5 psi). Maximum
Pressure setting is 14 psig. The set point is usually less than 5 psig.
Original equipment with this boiler is a Honeywell PA404A1009. Boiler operation is interrupted
when the steam pressure exceeds the the “CUT IN” pressure plus the differential. Boiler operation
resumes automatically when the system pressure falls below the “CUT IN” pressure.
1b. Limit (Water Boiler). An electrical device that automatically interrupts the boiler operation when
the water temperature exceeds the set point. Maximum temperature setting is 220°F.
Boiler operation is interrupted when the water temperature exceeds the set point. Boiler operation
resumes automatically when the water temperature falls to approximately 15°F below the set point.
1c. Limit Control may incorporate a low water cut-off feature that will interrupt boiler operation upon
loss of water in the boiler. If the low water cut-off function is activated to interrupt boiler operation,
follow the instructions TO TURN OFF GAS TO THE APPLIANCE (see Figures 3-5) and contact a
qualified service agency.
2. Flame Rollout Switch (FRS). An electrical device that automatically interrupts the boiler operation
when excessive heat is present in the combustion area. The control is a thermal fuse device that
will require replacement if it is activated. If the control has been activated to interrupt the boiler
operation, do not attempt to restart the boiler. Contact a qualified service agency.
3. Blocked Vent Switch (BVS) An electrical device that automatically interrupts the boiler operation
when there is a blockage in the vent pipe or chimney. The control is located on the side of the draft
hood and is a manual reset device. If the control is activated to interrupt operation of the boiler, do
not attempt to restart the boiler. Contact a qualified service agency.
WARNING
CAUTION
