LAARS NeoTherm NTV (Sizes 399-850 MBTU/h) - Service Manual - Manual (Page 37)

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Service Manual - NeoTherm 500
Removing and Replacing the Gas Valve (continued)
B11
cont.
5. Disconnect the small vacuum hose running to the
top of the gas valve.
6. Disconnect the wires to the high gas pressure
switch only. (On the unit, this is the pressure
switch on the left, on the side closest to the
blower. See Fig. B11-3.) Remove the front cover
on the gas switch by removing the two screws.
Before disconnecting the wires, note the way
they are connected to the switch. Mark the wire
on the left using a piece of electrical tape. When
the switch is re-connected, this wire will go to the
“N.C.” connection.
7. On the left end of the assembly, remove the
four bolts which attach the gas assembly to the
blower. See Fig. B11-4. The 5/16” socket will fit
the head of each bolt. Use the 3/8” socket on the
nut on the other end.
8. On the right end of the assembly, remove
the four socket-head cap screws which at-
tach the gas inlet pipe to the assembly. See
Fig. B11-5. Use the 4mm Allen wrench. Notice
that the two screws on the bottom of the assem-
bly are shorter.
Mark this wire
with a piece of
tape.
Fig. B11-3 - High gas pressure switch - cover removed
Fig. B11-4 - Undo the four screws at the left end of
the assembly
Undo these
screws.
Fig. B11-5 - Undo the four screws at the right end of
the assembly
Undo these
screws.
Wire to N.C.
contact