Heater placement and clearances
The GWH-425-HNO is design certified for installation
directly on a combustible wall. (see 3.4 Mounting
installation) For installation on vinyl siding see Fig. 7.
Keep the area below the heater free of combustible
If the appliance is installed under an overhang, there
must be a 36" clearance from the top of the appliance
and the mounting area must be open in front and on the
sides of the appliance.
Danger: The top of the kit will get hot
due to the flue gases. Install away from
Directly below or from an
opening; operable windows,
doors and any fresh air
From any adjacent wall or tall
Below a gutter, sanitary
pipework, eaves or overhang
From a gas meter, gas
regulator, electrical box or
another 425-HNO heater.
Table 2 Clearances
To remove front cover.
B Loosen the two screws located on the sides of the
front panel, see Fig. 6.
B Ensure that the flue terminal is clear of any
B After inspection, replace front cover and tighten
≥ 4 ft
B Install only on an external wall, as close as possible
to the most frequently used hot tap (note clearances
≥ 4 ft
in chapter 3.3.
B If the unit is to be installed on a combustible surface
≥ 3 ft
use the enclosed heat shield (see Fig. 5).
≥ 1 ft
≥ 3 ft
Warning: before starting installation:
B check that there are no loose parts
inside the appliance
B ensure that gas pipe, gas valve, and
burner have no damage and are
Front cover should be removed in order to
Remove front cover
Warning: Do not mount heater directly
to vinyl siding. With vinyl siding
surfacing, a 6' x 4' area of the siding
must first be covered or replaced with
other non-plastic made
material. See Fig. 7.
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