LAARS NeoTherm NTV (Sizes 399-850 MBTU/h) - Service Manual - Manual (Page 82)

72 Service Manual - NeoTherm 500
4. Clean the heat exchanger by brushing away any
soot with the toilet brush, and collecting the dust
using a vacuum cleaner. Use the vacuum to remove
any mineral granules.
Caution! Do not use a stiff brush with wire bristles.
This can scratch the tubes on the heat exchanger.
Note - It is not necessary to remove the refractory
material at the far end of the heat exchanger.
5. Once the tubes are clean, rinse them with white
vinegar. You do not need a lot of vinegar to do this
- just enough to flush any remaining dust out of the
spaces between the coils.
Reassembly Procedure:
1. To reassemble, reverse the procedure we have just
listed.
2. Replace the gasket on the inner surface of the cover
for the heat exchanger. Figure C5-15 shows how
the gasket should sit in its slot. Replace the gasket
(p/n R2069400) if it is damaged.
3. When attaching the front cover of the heat exchang-
er, tighten the nuts in a cross-pattern. See Fig. C5-
16. (If you tighten all of the nuts on one side first,
this might bend or distort the cover.)
4. The gas valve includes a rubber washer. See Fig.
C5-17. Be sure to insert this in the correct position
when replacing the valve.
5. The gas valve has an On/Off switch. When replac-
ing the valve, be sure this is set to On.
6. When re-attaching the gas inlet, remember to posi-
tion the O-ring correctly. Replace the O-ring if it is
damaged. To connect the gas inlet pipe, start by
inserting the right rear screw, but do not tighten it
completely. This will make it easier to line up the
right front screw.
7. Check for gas leaks using a leak detection solution.
8. Finish reassembling the unit and turn on the power
and gas. Check for proper venting and combustion
air. Fire the boiler and check the combustion using a
combustion analyzer.
Fig. C5-15 - Gasket in correct position
Fig. C5-16 - Tightening sequence for nuts on front cover
On/Off switch
Fig. C5-17 - Gas valve and rubber washer
Cleaning the Burner and Heat Exchanger (continued)
2 3
4
5 6
1
Rubber washer
C5
cont.