Mighty Therm VW - PW Volume Water Heaters
Page 5
d.
Disengage the flue transition ring from the stack
extension and place it on top of the collector
assembly as shown in Figure 4.
e.
Slide the adapter plate over the bottom of the
stack extension as shown in Figure 5. Fit the
stack extension down over the flue transition
ring. Seat the adapter plate on the top assembly
and secure it with two screws (see Figure 6).
f.
Indoor models, size 175 and 250 only, require an
adapter cable (included with product). The cable
connects the blocked vent safety switch (BVSS)
on the bell of the external draft hood to the 6-
position Molex plug on the side of the unit (see
Figure 7). Refer to instruction sheet included
with cable.
2C. Site Location
2C-1. Installation Information
WARNING
Improper installation or maintenance can cause
nausea or asphyxiation from carbon monoxide in
flue gases which could result in severe injury,
property damage, or death.
Avoid placing the heater in locations where it can
be damaged by water or condensate leakage. If this is
not possible, provide a suitable drain pan to catch and
divert any leakage. The pan must not block natural
flow of air around the heater.
Locate the heater to provide adequate clearance
on all sides for inspection, service and to provide
adequate air circulation for proper operation.
Locate the heater so the clearances from
combustible surfaces shown in Table 1 and Figure 8
are met.
Figure 8. Alcove installation.
Closet Installation
(unacceptable)
A closet is any 4 sided enclosure
which is less than 16* times the
total volume of all the gas fired
appliances within the enclosure.
Room Installation
(acceptable)
A room is any enclosure which is
at least 16* times greater than the
total volume of all the gas fired
appliances within the enclosure
Alcove Installation
(acceptable)
An alcove suitable for the
installation of a heater is a
restricted section of a room not
separated from the room by a door
or partition and which meets the
minimum clearances specified in
this manual.
* When the ceiling height exceeds 8 feet, you are only allowed to consider
8 feet when calculating the total volume of the enclosure.
Indoors
Outdoors
Clearance from:
inch
mm
inch
mm
Top
37
940
Unobstructed
Water conn. side
12
305
Unobstructed
Opposite side
6
152
6
152
Front
Alcove
Unobstructed
Rear
6
152
6
152
Vent*
6
152
—
Flooring
Combustible
Combustible
Service clearance = 36 inches (914mm) at front of heater,
and 18 inches (457mm) at water connection side.
*1" (25mm) if double wall vent is used.
Table 1. Minimum Boiler Clearances
from Combustible Surfaces.
Locate the heater on a waterproof floor with a
floor drain and a 6 inch (152 mm) minimum curb on
all four sides to protect the building if heater repairs
are needed.
2C-2. Outdoor Installation (U.S. Only)
Caution
Outdoor installations are not recommended in areas
where the danger of snow blockage exists. VW-PW
heaters can be installed in the standard low-profile,
grate top configuration as received from the factory,
or with an optional vent cap.
Locate the heater in an open, unroofed area. Do
not locate the heater below or adjacent to any doors,
windows, louvers, grills, etc., which connect in any
way with an inhabited area of a building, even though
the access might be through another structure such as a
garage or utility room (see Figure 9 and Table 1).
There must be a minimum of 4 feet (1.22 m)
horizontally and vertically between the heater and any
door, window, or gravity inlet to a building (see
Figure 10).
If the heater is installed close to a structure,
protect it from rain water runoff with rain gutters on
the roof or other measures. Do not locate the heater
near sprinkler systems that could spray water on it.
