PART 1 GENERAL
Provide gas-fired unit heaters, designed and manufactured for
indoor use.
1.1 SECTION INCLUDES
A. Unit Heater
B. Controls
1.2 REFERENCES
A. American National Standards Institute (ANSI) / Canadian
Standards Association (CSA): Establish requirements applicable
to construction, certification and installation of unit heaters.
a. Standard ANSI Z83.8 / CSA 2.6 “Gas Unit Heater and Gas-
Fired Duct Furnaces” (latest edition)
B. IAS: Establishes requirements applicable to construction and
certification of unit heaters.
a. Standard No.10-96 “Unit Heaters for Residential Use”
(latest edition)
C. National Fire Protection Association (NFPA): Establishes fire
prevention standards.
a. Article 54: National Fuel Gas Code (latest edition)
b. Article 70: National Electric Code (latest edition)
1.3 SUBMITTALS FOR REVIEW
A. Product Data: Provide data with dimensions, service
connections, accessories, controls, electrical nameplate data and
wiring diagrams.
1.4 PROJECT CLOSEOUT PROCEDURES
A. Training: Provide owner with verbal operating instructions as
well as original manufacturer’s installation, operation and service
manuals.
1.5 QUALITY ASSURANCE
A. Manufacturer Qualifications: Company specializing in
manufacturing the products specified in this section (gas-
fired unit heaters) with a minimum of ten years documented
experience. Equipment shall be the standard product of the
manufacturer and shall have complete catalogued data.
B. Installer Qualifications: All installation and service of unit
heaters must be performed by a contractor qualified in the
installation and service of said products with proof of a
minimum of three years documented experience.
C. Factory Testing: Each unit heater shall be factory tested. Testing
shall consist of verification of correct operation of burners,
manifold, control assembly and electrical components.
1.6 REGULATORY REQUIREMENTS
A. Conform to ANSI Z83.8 / CSA 2.6, latest edition, and provide
evidence that the unit heater and its control system have been
found in compliance with these standards by a nationally
recognized testing laboratory.
1.7 WARRANTY
A. The product shall have a manufacturer’s limited warranty of at
least 24 months, subject to the manufacturer’s standard warranty
limitations.
PART 2: PRODUCTS
2.1 MANUFACTURERS
A. COMBAT® by Roberts-Gordon UHA[X][S]-Series
2.2 MANUFACTURED UNITS
A. Unit: Gas-fired, power-vented unit heater with tubular heat
exchanger. Units shall have a minimum of 82% thermal
efficiency. The standard unit shall consist of a non-separated
combustion design with an aluminized heat exchanger. Design
and heat exchanger alternatives shall be offered as follows:
1. Separated Combustion: A separated combustion unit shall
consist of an enclosed sealed burner box to which
combustion air is vented through a piece of internal flexible
air duct. This duct terminates at an exterior cabinet flange to
which a vent run to the outside of the heated space should be
attached.
2. Stainless Steel Heat Exchanger: A stainless steel heat
exchanger unit shall consist of heat exchanger tubes, heat
exchanger tube supports, heat exchanger tube plates and a
vent box produced of 409 stainless steel.
2.3 FABRICATION
A. Casing and Components: Galvannealed steel panels, minimum
20 gauge. All panels shall be lined with a minimum of
3/8"(10mm) thick insulation.
B. Access Door: Door shall be provided for easy service of all
critical components.
C. Finish: Standard finish is a heavy-duty white powder-coat.
D. Louvers: The cabinet shall be equipped with horizontal louvers.
Louvers shall be spring-held and adjustable for directing airflow.
2.4 HEAT EXCHANGERS, BURNERS AND GAS TRAIN
A. Heat Exchangers: For Models 30-125, heat exchanger tubes
shall be of a six-pass design with 1.5" (38 mm) outer diameter
[aluminized steel] [409 stainless steel] tube. For Models 150-
400, heat exchanger tubes shall be of a four-pass design with
1.75" (44 mm) outer diameter [aluminized steel] [409 stainless
steel] tube. Heat exchangers shall not be clamshell design. For
Models 150-400, the heat exchanger tubes shall be dimpled to
provide efficient heat transfer. The tube plates shall be made of
[aluminized steel] [409 stainless steel]. The tube supports shall
be made of [galvannealed steel] [409 stainless steel].
B. Burners: The burners shall be in-shot type, directly firing each
heat exchanger tube individually. Burners shall be capable of
burning natural gas or LPG.
C. Gas Train: The gas train is constructed of black pipe and includes
a single-stage gas valve. The valve provides the regulator, main
gas and manual shutoff functions.
GAS-FIRED UNIT HEATER GUIDE SPECIFICATION
