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RESIDENTIAL GAS AND ELECTRIC WATER HEATER
SERVICE HANDBOOK
A.O. Smith Water Products Company Training Department
©2002 Ashland City, Tennessee
15
Residential Gas – continued
Exhaust Venting Notes
Follow current National Fuel Gas Code requirements for proper installation.
“D” – Typically, same or larger diameter as Draft Hood
outlet
“L” – Horizontal piping slopes upward ¼” per foot from
heater to chimney or vertical vent
Length of horizontal not more than 75% of “H”
“H” – Not less than 5 feet
Maximize vertical distance to first elbow
See the “Technical Bulletins Section “ of this manual for explanations of:
Water Hammer
Mineral Buildup
Aluminum Hydroxide
Condensation
Discolored Water
Smelly Water
Chlorination Process
Lack of hot water
Thermal Expansion
Temperature and Pressure Relief Valve Operation
Parts Replacement
– The parts on these models change often due to improvements/changes
in the products. To order the current, correct replacement part for your model gas water heater,
you must know the model number and (complete) serial number of your water heater. This
information will be located on a black and white label, on the front of your water heater – this label
will also display a star within a circle (the A.G.A. symbol). A sample might be:
Model “PGCG-50 – 242” “Ser No. MB99-(numbers) – 242”.
To order parts, contact your local A.O. Smith Contractor or Distributor, phone AOS
parts at 800-433-2545 or contact A. O. Smith on Web site “www.hotwater.com”