Installation Sheet

14 Page
Combustible air supplied by mechanical fan or make up air device
The water heater is equipped with a combustible air sensor that will shut off the unit when inadequate com-
bustible air supply to unit is detected.
• If a mechanical fan or make up air device is used to supply air to the water heater or utility room, the
installer should make sure it does not create drafts which could cause nuisance shutdowns.
• If a blower is necessary to provide adequate combustion air to the water heater, the blower and water
heater must be set up so that the water heater cannot fire unless the blower is operating. Possible
methods include the use of the water heater internal fan control port or the use of external flow sensors/
transmitters and relays.
-Direct intake vent system-
This water heater may be converted to a direct-vent (sealed combustion) appliance by installing an adapt-
er 100112186 (TM-DV50) which will bring all required combustible air from outside the building. When
installing the direct-vent conversion kit, please follow all instructions included with the kit.
• The water heater must be installed in a location where the proper amount of combustible air will be
available to it at all times without obstructions.
• If used as a direct-vent appliance, the water heater
requires a 5” (127 mm) combustible air supply pipe. The
intake pipe must be sealed airtight.
• Air supply pipe can be made of ABS, PVC (solid core),
CPVC (solid core), galvanized steel, corrugated aluminum,
corrugated stainless steel or Category III stainless steel.
• Use of cellular core PVC (ASTM F891), cellular core CPVC,
or Radel® (polyphenylsulfone) in non-metallic venting
systems is prohibited. Covering non-metallic vent pipe
and fittings with thermal insulation is prohibited.
• Change the DIP switch settings to the direct-vent system.
(See diagram below.)
• Sidewall venting is recommended for the direct-vent
system.
• The manufacturer recommends running the exhaust vent
and the intake pipe parallel.
• For the venting instructions for direct intake vent installa-
tions, refer to pp. 15 to 20.
5”Intake air port
Exhaust
Louver cover plates
Direct vent
conversion kit
Installaon
Installaon Manual
WARNING
• To change the DIP switch settings for direct vent installation, locate the lower bank of
DIP switches at the bottom of the center computer board as shown below.
• Only adjust the appropriate DIP switches as shwon below.
• Turn off the power supply to the water heater before changing the DIP switch settings.
• Failure to observe this warning could result in carbon monoxide poisoning or death.
ON
MST
P-ALARM
OUT DIRE MODE TMP3 TMP2 TMP1
87654321
The dark squares indicate the correct
positions of the DIP switches.
The lower bank of DIP switches
ON
OFF