LAARS NeoTherm NTV (Sizes 150–285 MBTU/h) - Service Manual - Manual (Page 69)

59 Service Manual NeoTherm 80 - NeoTherm 285
Cleaning the Burner and Heat Exchanger
The buildup of black carbon soot on the external surfaces of the heat
exchanger can be caused by one or more of the following: incomplete
combustion, combustion air problems, venting problems, and short-
cycling. Soot buildup or other debris on the heat exchanger may restrict
the flue passages.
Laars recommends the unit be inspected once a year, and cleaned if
necessary. If a condensing boiler is operated consistently at high tem-
peratures, it may need to be cleaned more often.
In order to clean the unit, it is necessary to remove the front of the heat
exchanger. Because of the way the air-gas channel is attached to the
blower, the simplest way to do this is to remove the whole air-gas chan-
nel/ blower/ gas valve assembly. This will require you to disconnect the
gas inlet first.
Figure C5-1 shows how the parts are arranged.
Gas valve
Rubber inlet
hose
Air-gas
channel
Blower
Front of heat
exchanger
Fig. C5-1 - Front of heat exchanger and other parts
(typical - NT105 shown)
Tools and equipment required:
Disassembly/ Reassembly:
• Combustion analyzer
• 3 mm and 4 mm Allen wrenches
(traditional “L” shaped, ball-head
type is best)
• Socket wrench with 10 mm socket
and 4” extension
• #25 Torx® driver
• Gas leak detection solution (i.e.
Hercules Megabubble®)
• Electrical tape
• Replacement gasket for front of
heat exchanger
• Container for removed parts
Cleaning:
• Long-handled toilet brush or other
soft brush
• Furnace vacuum (i.e. SootMaster ®)
• Drain hose (approx. 6’)
• White vinegar
C5