Laars MASCOT LX, Руководство по обслуживанию

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47
Mascot LX Service Manual
Gas Valve
B13
Fig. B13-1 - Upper part of cabinet
(typical installation, front cover removed)
The modulating gas valve consists of a valve body that
controls the on/off gas flow, and a pressure regulator. In
combination with the Venturi, it provides the air/gas ratio
control.
Tools and equipment required:
• Combination wrench set
• Allen wrench set
• Two pipe wrenches
Replacement procedure:
1. Switch off the power switch on the front panel to turn
off power to the machine.
2. Remove the upper front panel.
3. Turn off all manual gas valves connecting the boiler
to the main gas supply line.
4. Disconnect the wiring harness for the gas valve. It is
held in place by a small Phillips-head screw.
5. Undo the two cap-head screws that support the end
of the air line. This assembly hangs from the end
of the Venturi. The air line runs to the air pressure
switch. Once the assembly is free, swing the end of
the air line out of the way to the left.
6. Loosen the union nut between the gas inlet pipe and
the gas valve. Be careful not to drop the O-ring.
7. Separate the Venturi from the blower. Use an Allen
wrench to remove the cap screws on the Venturi
mounting plate. This will allow you to remove the
gas valve and Venturi together.
8. You can separate the gas valve from the Venturi by
pulling them apart while twisting slightly.
9. To reassemble, reverse the steps listed above.
After re-tightening the union in the gas line, check
for gas leaks using a leak detection solution.
Union in
gas line
Air line to
pressure
switch
Venturi
Gas valve
Remove these
cap screws