Condensate Ph Level; High Altitude Installations; Filling The Water Heater - A.O. Smith 300 Series Instruction Manual

Note: If the "Blocked Exhaust " Fault message is ever displayed
on the control system LCD, check the condensate drain first
and ensure it is not blocked.
EXHAUST (VENT)
ELBOW
CONDENSATE
DRAIN LINE
CONNECTION
CONDENSATE
CLEANOUT CAP
CONDENSATE DRAIN
LINE - FIELD INSTALLED
Figure 15. Condensate Drain Configuration
DO NOT remove the factory installed exhaust/condensate elbow
for any reason. See Figure 15. The water heater's vent pipe is under
a slight positive pressure while unit is in operation. The water trap
inside of the exhaust/condensate elbow prevents flue gases from
escaping into the installed space.
Do not install any external condensate trap. The exhaust elbow
assembly has an internal condensate trap.

CONDENSATE PH LEVEL

The condensate drains from the water heater's covered in this
manual have pH levels between 4.3 and 5.0. Install a commercially
available neutralizing kit if required by local codes.
Note: Lower pH levels are acidic. Do not connect a metal drain
line, such as copper, to the water heater for this reason. See
Condensate Drain Installation (page 35).

HIGH ALTITUDE INSTALLATIONS

Breathing Hazard - Carbon Monoxide Gas
• Special consideration must be taken with
installations above 10,000 feet (3,048 m)
refer to high altitude section of this
manual.
• Contact an AO Smith qualified service
agent to obtain the proper setup and
instructions before lighting.
• Failure to implement the proper setup will
result in improper and inefficient
operation of the appliance resulting in
production of increased levels of carbon
monoxide gas in excess of the safe
limits which could result in serious
personal injury or death.
Breathing carbon monoxide can cause brain damage or death.
Always read and understand the instruction manual.
This high efficiency water heater is certified for use without
modification for an altitude of 10,100 feet (3,078 m). Consult the
factory for installation at altitudes over 10,100 feet (3,078 m).
Some gas utility companies derate their gas for altitude, making
it unnecessary to install high altitude orifices. Call the local gas or
utility company to verify BTU content.
Due to the input rate reduction at high altitudes, the output rating of
the water heater is also reduced and should be compensated for in
the sizing of the equipment for applications.
THIS SIDE VIEW
OF EXHAUST
ELBOW AND
ARROW INDICATE
THE LOCATION OF
THE PRESSURE
PORT
DRAIN LINE TO TERMINATE NO
MORE THAN 6 INCHES (15.2cm)
ABOVE DRAIN
BUILDING
DRAIN
22

FILLING THE WATER HEATER

Never use this water heater unless it is completely full of water.
To prevent damage to the tank, the tank must be filled with water.
Water must flow from the hot water faucet before turning ON gas
to the water heater.
To fill the water heater with water:
Close the water heater drain valve by turning the handle to the
1.
right (clockwise). The drain valve is on the lower front of the
water heater.
Open the cold water supply valve to the water heater.
2.
Note: The cold water supply valve must be left open when the
water heater is in use.
To insure complete filling of the tank, allow air to exit by opening
3.
the nearest hot water faucet. Allow water to run until a constant
flow is obtained. This will let air out of the water heater and the
piping.
Check all water piping and connections for leaks. Repair as
4.
needed.