3. Remove the front cover, and then remove the boiler's top panel by removing the four Torx head
screws on the top panel 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. Remove the bolt and nut securing the gas valve bracket to the frame.
5. Remove the Phillips head screw (see
j
on
) from the power connector plug, and pull
off the electrical connector from the gas valve.
6. Remove the two screws of the bracket supporting the gas valve on the inlet side (see
).
Figure 72
Removing two screws of bracket and Phillips head screw on gas valve inlet side
7. Pull the black tubing (see
on
) from the push-to-connect fitting on the gas valve outlet
side.
8. Disconnect the three- (3) wire Molex plug from the gas pressure switches.
9. Unscrew the two (2) bolts of the flange to separate the gas valve inlet from the gas line. Keep
gasket and bolts for re-assembly. (See
l
on
.)
10. Unscrew the four (4) bolts of the flange to separate the gas valve outlet from the gas line. Keep
gasket and bolts for re-assembly. (See
o
on
.)
11. Remove the gas valve and install the new gas valve.
12. Re-install the components in reverse order of the steps above.
13. Turn on the electric power and gas supply to the boiler.
14. Reset the low pressure switch. For instructions, see
Resetting the gas high / low pressure
.
15. Tune the gas valve. For instructions, see
Adjusting the gas valve (EX 700, EX 850) on page 76
.
99
7.3.2 Replacing the gas valve in EX 700 and EX 850 models
Summary of Contents for EX Series
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Page 121: ...Appendices Wiring diagrams Figure 73 Controller electrical diagram 119 Appendices...
Page 122: ...Figure 74 Internal wiring diagram EX 400 and EX 500 models 120 Section Appendices...
Page 123: ...Figure 75 Internal wiring diagram EX 700 and EX 850 models 121 Wiring diagrams...
Page 124: ...Figure 76 Sequence of Operation 122 Section Appendices...
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Page 128: ...126 Boiler parts diagram EX 400 and EX 500...