User Guide
FOR YOUR SAFETY
The use and storage of gasoline or other 
flammable vapors and liquids in open 
containers in the vicinity of this appliance 
is hazardous.
IMPORTANT
All installation and service of these 
units MUST be performed by a qualified 
installation and service agency.
  CAUTION
To prevent premature heat exchanger 
failure do not locate ANY gas-fired units in 
areas where chlorinated, halogenated or 
acid vapors are present in the atmosphere.
  WARNING
If the information in this manual is not 
followed exactly, a fire or explosion may 
result, causing property damage, personal 
injury or death.
  WARNING
Improper installation, adjustment, 
alteration, service or maintenance can 
cause property damage, injury or death, 
and could cause exposure to substances 
which have been determined by various 
state agencies to cause cancer, birth 
defects or other reproductive harm.
RESIDENTIAL OWNER’S MANUAL
gas-fired unit heaters
models HD, HDB, HDS, and HDC
6-577.4
5H75225A Rev. C
All models approved for use in California by the CEC,  
in New York by the MEA division, and in Massachusetts. 
Unit heater is certified for residential and commercial 
applications. 
THIS MANUAL IS THE PROPERTY OF THE OWNER. 
PLEASE BE SURE TO LEAVE IT WITH THE OWNER WHEN YOU LEAVE THE JOB. 
May, 2007
FOR YOUR SAFETY
WHAT TO DO IF YOU SMELL GAS:
•  Open windows.
•  Do not try to light any appliance.
•  Do not touch any electrical switch; do not 
use any phone in your building.
•  Immediately call your gas supplier from 
a neighbor’s phone.  Follow the gas 
supplier’s instructions.
•  If you cannot reach your gas supplier, call 
your fire department.




