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Heatilator • NNXT4236IF, NNXT4236ILF, NNXT3633IF, NNXT3633ILF Installation Manual • 4055-980 Rev. D • 9/15
Lift top refractory
and hold in place
Pull side refractory
forward & out
Figure 4.11b Remove Side Refractory
• Remove the side refractory:
- Gently raise the front of the top refractory.
- Lift the side piece up slightly and then out.
• Remove top refractory:
- Lower towards side removed in previous step.
- Gently twist out.
Lower & twist; pull out
Figure 4.11c Remove Top Refractory
• Remove two screws from
fi
rebox top.
• Using these screws and the same holes, install the top
vent
fl
ue baf
fl
e.
- The
fl
ue baf
fl
e will be turned to install below the level
of the
fi
rebox top for 12-30 ft vertical runs of vent.
See Figure
4.11
d.
- The
fl
ue baf
fl
e will be turned to install inside the
fl
ue
for vertical vent runs of 31-60 ft. See Figure 4.11e.
Figure 4.11d 12-30 ft Vertical Run
Figure 4.11e 31-60 ft Vertical Run
Place flue visor,
reinsert screws
Place flue visor,
reinsert screws
• Reinstall
Refractory:
- Replace top refractory.
- Lift top refractory and slide side refractory back into
position.
- Replace bottom retainer.
