LAARS NeoTherm NTV (Sizes 399-850 MBTU/h) - Service Manual - Manual (Page 75)

65 Service Manual - NeoTherm 500
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.
Fig. C5-1 - Front of heat exchanger and other part
Tools and equipment required:
Disassembly/ Reassembly:
• Socket wrench with 10 mm and 13
mm sockets and 4” extension
• 5/16” and 3/8” sockets or combina-
tion wrenches
• #25 Torx® driver
• Flat-blade screwdriver
• 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
Air-gas channel
Blower
Front of heat
exchanger