Sterling TD User Manual
Page 3

3
GENERAL SAFETY INFORMATION
Failure to comply with the general
safety information may result in extensive 
property damage, sever personal injury, or death.
This product must be installed by
a licensed plumber or gas fi tter when installed 
within the Commonwealth of Massachusetts.
Installation must be made in accordance with local 
codes, or in absence of local codes, with the latest 
edition of the National Fuel Gas Code, ANSI Standard 
Z223.1 (NFPA 54). All of the ANSI and NFPA Standards 
referred to in these installation instructions are those that 
were applicable at the time the design of this appliance 
was certifi ed. The ANSI Standards are available from the 
CSA Information Services, 1-800-463-6727, as well as at 
www.ansi.org. The NFPA Standards are available from the 
National Fire Protection Association, 1 Batterymarch 
Park, Quincy, MA 02169, as well as at www.nfpa.org. 
These duct furnaces are designed for use in airplane 
hangars when installed in accordance with current ANSI/
NFPA No. 409 and in public garages when installed in 
accordance with current NFPA No. 88A and NFPA No. 88B.
If installed in Canada, the installation must conform with 
local building codes, or in absence of local building codes, 
with CSA-B149.1 “Installation Codes for Natural Gas 
Burning Appliances and Equipment” or CSA-B149.2 
“Installation Codes for Propane Gas Burning Appliances 
and Equipment.” These indoor duct furnaces have been 
designed and certifi ed to comply with CSA 2.6. Also see 
sections on installation in AIRCRAFT HANGARS and 
PUBLIC GARAGES.
Do not alter the duct furnace in any
way or damage to the unit and/or severe personal 
injury, or death may occur!
Disconnect all power and gas
supplies before installing or servicing the heater. 
If the power disconnect is out of sight, lock it in 
the open position and tag it to prevent unexpected 
application of power. Failure to do so could result 
in fatal electric shock, or severe personal injury.
Ensure that all power sources conform
to the requirements of the unit heater or damage to 
the unit will result!
Follow installation instructions CAREFULLY to avoid 
creating unsafe conditions. All wiring should be done and 
checked by a qualifi ed electrician, using copper wire only. 
All external wiring must conform to applicable local codes, 
and to the latest edition of the National Electric Code 
ANSI/NFPA No. 70. All gas connections should be made 
and leak-tested by a suitable qualifi ed individual, per 
instructions in this manual.
Also, follow procedures listed on the “Gas Equipment 
Start-up” sheet located on the back cover of this manual.
Use only the fuel for which the heater is designed (see 
rating plate). Using LP gas in a heater that requires 
natural gas, or vice versa, will create the risk of gas leaks, 
carbon monoxide poisoning and explosion.
Do not attempt to convert the
heater for use with a fuel other than the one 
intended unless using an appropriate conversion 
kit provided by the manufacturer. Such conversion 
is dangerous and could create unsafe conditions 
that result in death, serious personal injury or 
property damage.
Make certain that the power source conforms to the 
electrical requirements of the heater.
Do not depend upon a thermostat
or other switch as sole means of disconnecting 
power when installing or servicing heater. Always 
disconnect power at the main circuit breaker as 
described above. Failure to do so could result in 
fatal electric shock.
Special attention must be given to any grounding 
information pertaining to this heater. To prevent the risk 
of electrocution, the heater must be securely and 
adequately grounded. This should be accomplished by 
connecting a grounded conductor between the service 
panel and the heater. To ensure a proper ground, the 
grounding means must be tested by a qualifi ed technician. 
Do not insert fi ngers or foreign objects into the heater or 
its combustion air moving device. Do not block or tamper 
with the heater in any manner while in operation or just 
after it has turned off, as some parts may be hot enough 
to cause injury.
This heater is intended for general heating applications 
ONLY. It must NOT be used in potentially dangerous 
locations such as fl ammable, explosive, chemical-laden 
or wet atmospheres. 
In cases in which property damage may result from 
malfunction of the heater, a backup system or a 
temperature sensitive alarm should be used.
The open end of gas piping systems
being purged shall not be discharged into areas 
where there are sources of ignition or into confi ned 
spaces UNLESS precautions are taken as follows: (1) 
By ventilation of the space, (2) control of purging rate, 
(3) elimination of all hazardous conditions. All 
precautions must be taken to perform this operation 
in a safe manner!
Unless otherwise specifi ed, the following conversions 
may be used for calculating SI unit measurements:
1 foot = 0.305 m
1 inch = 25.4 mm
1 gallon = 3.785 L
1 pound = 0.453 kg
1 psig = 6.894 kPa
1 cubic foot = 0.028 m
3
1000 BTU per hour = 0.293 kW
1 inch water column = 0.249 kPa
1000 BTU/Cu.Ft. = 37.5 MJ/m
3
Liter/second = CFM x 0.472
Meter/second = FPM ч 196.8
