Requirements; Unit Heater Installation; Combustion & Ventilation Air; Venting - Mr. Heater MHU 50 Mode D'emploi

These units are certified for residential applications. For
installation in a residential garage, these units must be installed
so that burners and ignition source are located no less than 18‰
(457mm) above floor. Heater must be located or protected to
avoid physical damage by vehicles. Refer to CSA B149.1, Natural
Gas and Propane Installation Code current edition.
In a confined area, the heater must be installed in accordance
with the CSA B149.1, Natural Gas and Propane Installation Code.
Be sure to check with local codes and ordinances for additional

requirements.

UNIT HEATER INSTALLATION

Unit is shipped ready for installation. Unit may be installed as
shown in figure 1 or inverted 180
as governed by clearances, vent connection, air direction, gas
supply, electrical supply and service accessibility.
1. If installing unit in an inverted position: Remove and retain
screws securing door and rotate door 180
retained screws. Rotate louvers directing airflow as desired.
2. Choose location for mounting brackets.
3. Remove and retain three screws along top edge (bottom
edge when inverted) of front of unit.
4. Align screw holes on mounting bracket with holes along
top edge (either upright or inverted) of unit. Secure one
mounting bracket to front of unit with retained screws.
Secure other mounting bracket to back of unit with screws
retained on the back of unit.
5. To support unit, secure mounting bracket to ceiling joist or
truss. Unit may also hang on rods as shown in figure 1.
INSTALL UNIT / UTILITY HEATER
MOUNTING
BRACKETS (2)
COMBUSTION AND VENTILATION AIR
Adequate facilities for supplying air for combustion and ventilation
must be provided in accordance with the latest edition of section
5.3, Air for Combustion and Ventilation, of the National Fuel
Gas Code, ANSI Z223.1, in the U.S.A., CSA B149.1 Natural Gas
and Propane Installation Code, or applicable provisions of local
building codes.
o depending on desired location
o . Secure with
FIGURE 1
SUPPORT
RODS
Compact Unit / Utility Heater
All gas fired appliances require air to be used for the combustion
process. In many buildings today, there is a negative indoor air
pressure caused by exhaust fans, etc. If sufficient quantities of
combustion air are not available, the heater or another appliance
will operate in an inefficient manner, resulting in incomplete
combustion which can result in the production of excessive
carbon monoxide.
CAUTION: Insufficient combustion air can cause headaches,
nausea, dizziness, asphyxiation or death.
If indoor air is to be used for combustion, it must be free of the
following substances or the life of the heat exchanger will be
adversely affected: chlorine, carbon tetrachloride, cleaning solvent,
halogen refrigerants, acids, cements and glues, printing inks,
fluorides, paint removers, varnishes, or any other corrosives.

VENTING

A – GENERAL RECOMMENDATIONS AND
REQUIREMENTS
NOTE: The vent is a passageway, vertical or nearly so, used to
convey flue gases from an appliance, or its vent connector, to the
outside atmosphere. The vent connector is the pipe or duct that
connects a fuel-gas burning appliance to a vent or chimney.
Unit heaters must be vented in compliance with all local codes
or requirements of the local utility, the current standards of the
(American) National Fuel Gas Code, ANSI Z223.1 or (Canada)
CSA B149.1 Natural Gas and Propane Installation Code, and the
following instructions.
A metal stamped/extruded transition is supplied with this certified
unit. It must not be modified or altered and must be installed
on the outlet of the induced draft blower assembly prior to the
installation of the vent or vent connector. Failure to comply with
this requirement will void the certification of the unit by the
approval agencies. All joints shall be secured with at least two
corrosion resistant screws. All joints must be checked for gas
tightness after installation.
B – VERTICAL VENTS USING METAL VENT
PIPE – COMMERCIAL AND RESIDENTIAL
INSTALLATIONS
MHU compact unit heaters are listed as Category I appliances for
vertical vent installations.
1. MHU 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‰ (76mm) diameter on 50k units
and 4‰(102 mm) diameter on 80k units. 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 Natural 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 cannot exceed the values in table 2.
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Operating Instructions and OwnerÊs Manual