INSTALLATION AND OPERATION INSTRUCTIONS
4-6
SL 26-260 G3, SL 40-399 G3 MODULATING GAS BOILERS
4.2.1 Fan and gas valve removal instructions
SL 26-260 G3
1. Turn off the electric power and gas supply to the boiler.
2. Ensure the boiler cools down to the surrounding temperature. Do not drain the boiler
unless freezing conditions are expected during this procedure.
3. Remove the front cover, and then remove the boiler upper-front cover by removing
the screws at the top right and left corner of the boiler.
A ladder or step may be required to have a clear vertical view of the work area. Do not
attempt to reach from the front without a clear view, as damage to connectors, screws
or refractory may occur.
4. Unplug both electrical connectors from the fan.
5. Unplug the electrical connector from the gas valve.
6. Position the harnesses out of the way of the heat exchanger lid.
7. Undo the brass nut between the valve and the venturi mixing device.
8. Remove the four 8 mm hex bolts that attach the fan to the lid.
9. Remove the fan and air intake venturi assembly from the boiler.
10. Separate the fan and the venturi mixing device by removing the 3 Phillips head
screws that attach the venturi mixing device to the fan.
11. Attach the venturi mixing device to the new fan.
12. Bolt the fan to the lid of the heat exchanger.
13. Attach the gas valve to the venturi mixing device with the brass coupler nut, ensuring
that the gasket is in place.
14. Connect the electrical connectors to the fan and gas valve.
SL 40-399 G3
1. Turn off the electric power and gas supply to the boiler.
2. Ensure the boiler cools down to the surrounding temperature. Do not drain the boiler
unless freezing conditions are expected during this procedure.
3. Remove the front cover, and then remove the boiler's upper-front cover by removing
the two Phillips head screws
at the top right and left corners of the boiler.
A ladder or step may be required to have a clear vertical view of the work area. Do not
attempt to reach from the front without a clear view, as damage to connectors, screws
or refractory may occur.
4. Unplug both the upper and lower electrical connectors from the fan.
5. Note the colors and positioning of the wire connectors,
and then unplug the electrical
connector from the gas valve by removing the 1/4” spade connectors.
6. Position the harnesses out of the way of the heat exchanger lid.
7. Remove the 4 hex head bolts using a 4 mm hex key that attaches the gas valve to
the venturi mixing device. These screws should be first loosened slightly in a cross
sequence to prevent deformation of the mating parts.
8. With the corrugated stainless steel gas line still attached to the gas valve, the gas
valve can now be separated from the venturi mixing device.
There is an O-ring
installed between the gas inlet block and gas valve, and it should remain positioned
on the block’s groove. If it falls out it is important that it be positioned back on the
groove or saved for re-assembly.
9. Remove the 4 hex nuts that attach the fan to the heat exchanger lid. A 7 mm open-
ended wrench or socket is required.
