Mr. Heater HST45 Operating Instructions And Owner'S Manual Download Page 13

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Operating Instructions and Owner’s Manual

Mr. Heater | Gas-Fired Low-Intensity Infrared Heater

The seams along the length of the piping and the joints
between sections of piping should be sealed to prevent a
potential leakage of flue gas into building. Use 100% RTV
Silicone Rubber Adhesive sealant suitable for 500°F.

6. All portions of the vent pipe shall be supported to prevent from

sagging.

7. When the vent pipe passes through areas where the ambient

temperature is likely to induce condensation of the flue gasses,
the vent pipe should be insulated and a condensation drain
should be provided.

8. The minimum clearance to combustible materials for single-

wall flue pipe shall be 6 inches. This may be reduced when the
combustible material is protected as specified in the National
Fuel Gas Code or the authority having jurisdiction.

9. Single-wall metal pipe shall not originate in any unoccupied attic

or concealed space and shall not pass through any attic, inside
wall or concealed space, or through any floor.

10. A venting system shall terminate at least 3 feet (0.9m) above any

forced air inlet located within 10 feet (3.1m).

b) Vent Termination

(Residential Installations)

1. The vent terminal shall terminate above the roof line so that no

discharge opening is less than 2 feet (0.6m) horizontally from
the roof surface. The lowest discharge opening will be no closer
than the minimum height specified in the following table. These
minimum heights may be used provided the vent is not less than
8 feet (2.4m) from any vertical wall or similar obstruction.

a) Be sure that method selected for venting heater complies with all

BASIC FLUE VENTING (Residential Only)

• Venting must be in compliance with the latest edition of the

National Fuel Gas Code (ANSI. Z223.1 latest edition: or the
authority having jurisdiction.

• Uninsulated single-wall metal pipe shall not be used outdoors in

cold climates for venting of these heaters as specified by Section
7.8 of the ANSI Z223.1/NFPA 54 National Fuel Gas Code-latest
edition.

• For the installation of a single-wall metal pipe through an

exterior combustible wall, refer to the latest edition of the
National Fuel Gas Code or the authority having jurisdiction.

• In regions of the country where prevailing winds are consistently

higher than 40 mph, it may be necessary to terminate the vent

system above the roof level.

Other venting references can be found in equipment volume of the
ASHRAE Handbook.

A. SINGLE HEATER VENTING

a) Vertical Through the Roof

NOTE: For residential applications, the heater must

not be connected to a separate chimney,
but must be installed using the venting
system as specified below.

1. When venting the heater to outside of building through a roof,

use 3 inch O.D. single-wall metal pipe. This is to be constructed
of galvanized sheet metal or other approved noncombustible,
corrosion-resistant material as indicated by state and/or local
codes.

2. A vent passing through a combustible roof shall extend through

a 2-inch clearance roof thimble. Double-wall, Type B vent must
be used for the portion of the vent system which passes through
the roof. An approved vent cap (such as Leslie “VersaCap” Type
B) must be attached to the end of the flue.

3. The maximum equivalent length of vent pipe should be carefully

observed. A safety switch in the heater is designed to shut
the heater off before excessive flue restriction causes bad

combustion.

Minimum Equivalent Length = 5 feet of Pipe

Maximum Equivalent Length = 25 feet of Pipe

Use the following correction factors to obtain the equivalent

length:

a) Subtract 15 feet if the run is horizontal.

b) Subtract 10 feet for an approved vent cap.

c) Subtract 10 feet for each elbow beyond 15 feet from the

heater.

d) Subtract 15 feet for each elbow within 15 feet of the heater.