INSTALLATION AND OPERATION INSTRUCTIONS
1-18
TANKLESS WATER HEATER 199
1.4.7 “Direct Vent” Combustion Air Intake Piping
The unit must always be installed as a Direct Vent venting system with the
combustion air piped directly from the outdoors to the unit’s combustion air
connection. Provisions for combustion and ventilation air are in accordance with
the section “Air for Combustion and Ventilation”, of the
National Fuel Gas Code,
ANSI Z223.1/NFPA 54
, or Clause 8.2, 8.3 or 8.4 of
Natural Gas and Propane
Installation Code, CAN/CSA B149.1
, or applicable provisions of the local building
codes.
Tankless
Water Heater
FLUE GAS
EXHAUST TO
OUTDOORS
COMBUSTION
AIR FROM
OUTDOORS
ALTERNATIVE
COMBUSTION AIR
CONNECTION
“DIRECT VENT”
INSTALLATION
CHECK AIR INTAKE
OUTSIDE TO MAKE SURE
IT IS CLEAR OF
OBSTRUCTIONS
FLUE GAS
EXHAUST TO
OUTDOORS
COMBUSTION
AIR FROM
OUTDOORS
ALTERNATIVE
COMBUSTION AIR
CONNECTION
Figure 20: Direct vent combustion air intake
Figure 19: Vent Terminal Clearance
Vent terminal
Air supply inlets
Area where terminal is not permitted
NOTE
Combustion air connection
may be moved from one side
to the other:
• Lift tab at back of plug
and rotate 1/8th of a
turn counter-clockwise
to remove from top of
cabinet.
• Lift tab at back of
combustion air connection
and rotate 1/8th of a
turn counter-clockwise
to remove from top of
cabinet.
• Reinstall plug and
combustion air connection
in the desired locations
then rotate 1/8th of a turn
clockwise until tab latches
into the top of the cabinet.