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Enerco | Compact Unit Heater Operating Instructions and Owner’s Manual
B – VERTICAL VENTS USING METAL VENT PIPE
– COMMERCIAL AND RESIDENTIAL
INSTALLATIONS
MHU/HSU compact unit heaters are listed as Category I
appliances
for vertical vent installations.
1. MHU/HSU unit heaters are to be used with NFPA- or ANSI-
approved
chimneys, U.L. listed type B-1 gas vents, single wall
metal
pipe, or listed chimney lining system for gas venting
where
applicable, as well as the modifications and limitations
listed
in figure 2 . Seal single wall vent material according to
the
section A - General Recommendations and Requirements.
2
. The vent connector shall be 3" (76 mm) diameter on 45 unit
and 4” (100mm) diameter for the 75 unit. In
all cases, a
flue
transition piece (supplied) is required to fit over the
outlet of the induced
draft assembly on the appliance.
3. Keep the vent connector runs as short as possible with a
minimum
number of elbows. Refer to the (American)
National Fuel Gas Code ANSI Z223.1 or (Canada) CSA B149.1
Na
tural Gas and Propane Installation Code for maximum vent
and
vent connector lengths. Horizontal run of the vent
connector
from the induced draft blower to the chimney/vent
cann
ot exceed the values in table 2 .
4. When the length of a single wall vent, including elbows,
exceeds 5 feet (1.5m), the vent shall be insulated along its
entire length with a minimum of 1/2" thick foil faced
fibe
rglass 1-1/2# density insulation. If a single wall vent is
used
in an unheated area it shall be insulated. Failure to do
so
will result in condensation of flue gases.
5. The unit may be vented vertically as a single appliance or as a
common
vent with other gas-fired appliances. In common
venting
situations, vent connectors for other appliances must
mai
ntain a 4" (100mm) vertical separation between the vent
connec
tors. Refer to common venting tables in the(American)
National Fuel Gas Code ANSI Z223.1 or (Canada) CSA B149.1
Natural
Gas and Propane Installation Code for proper vent
size
.
6. Clearance to combustible material is 6" (152mm) for single
wall vent material except where a listed clearance thimble
is used.
Clearance to combustible material for type B-1 vent or
factory-built
chimney is per manufacturer’s instructions.
7. The vent connector shall be supported without any dips or
sags.
Vertical vents shall be supported in accordance with
thei
r listing and manufacturers’ instructions. All horizontal
vent connector runs shall have a slope up to the vertical
vent of at least 1/4" per foot (1mm per 50mm).
8. All vertical type B-1 vents, single wall vents, or listed chimney
lining
system must be terminated with a listed ventcap or
listed
roof assembly.
9. The vent must extend at least 3' (1m) above the highest point
where
it passes through a roof of a building and at least 2’
(0.6m)
higher than any part of a building within a horizontal
distance
of 10' (3.05m) unless otherwise specified by the
(American)
National Fuel Gas Code, ANSI Z223.1 or (Canada)
CSA B149.1 Natural Gas and Propane Installation Code.
The
vent must extend at least 5' (1.6m) above the highest
connected
equipment flue
colla
r.
C – HORIZONTAL VENTING – GENERAL
Common venting is not allowed when horizontally venting the unit
he
ater.
The
minimum horizontal vent length is three feet (914mm).
1. If possible, do not terminate the horizontal vent through a wall that
is
exposed to prevailing wind. Exposure to excessive winds can
affect
unit performance. If such a termination is necessary, use a
wind block to protect the vent termination from direct wind.
2. Vent termination must be free from obstructions and at least
12" (306mm) above grade level and maximum snow height.
3. Do not terminate vent directly below roof eaves or above a
walkway, or any other area where condensate dripping may
be
troublesome and may cause some staining. Avoid windows
where
steam may cause fogging or ice buildup.
4. When horizontally vented, minimum clearance for termination
from any door, window, gravity air inlet, gas or electric meter,
regulators, and relief equipment is 4 ft. (1.2m) for U.S.
install
ations. Refer to NFPA 54/ANSI Z223.1 in the U.S.A. and
CSA B149.1 Natural Gas and Propane Installation Code
in
Canada or with authorities having local jurisdiction. In
Canada,
vent termination must have a minimum 6 ft.
(1.8mm) horizontal clearance from gas and electric meters
and
relief devices as specified in the CSA B149.1, Natural
Gas and Propane Installation
Code.
VENT TERMINATION ON SINGLE WALL VENT
SINGLE WALL TERMINATION
DOUBLE
WALL (TYPE B-1) TERMINATION
ROOF FLASHING
ROOF PITCHED
FROM 0” TO 45”
SHALL
NOT BE A
CONCEALED
SPACE
2”
CLEARANCE
THIMBL
E
ROOF FLASHING
ROOF PITCHED
FROM 0” TO 45”
12” MAX
CLEARANCE
TO BE AS
SPECIFIED
ON TYPE “B”
VENT PIPE
SEAL
JOINT BETWEEN SINGLE WALL VENT
AND
“B”VENT AND THE ANNULAR SPACE OF THE “B” VENT
FIGURE 2