A.O. Smith 404 Water Heater User Manual


 
46
all of the hardness (lime). For this reason it is recommended that a
regular schedule for deliming be maintained.
The time between cleaning will vary from two to six months
depending upon water conditions and usage. A change of
approximately 5
o
F (3°C) in the normal temperature rise through
the boiler is usually an indication that scale should be removed.
For long life, copper or brass is recommended for all valves, pipe
and fittings.
TUBE CLEANING PROCEDURE
MECHANICAL REMOVAL OF DEPOSITS
Establish a regular inspection schedule, the frequency depends
on the local water conditions and severity of service. Do not let
the tubes clog up solidly. Clean out deposits over 1/16" (1.6
mm) thickness.
To service heat exchanger tubes, remove return header casting
on the side opposite the water connections. Use a U.S. standard
5/8" deep socket ratchet to remove the nuts, exposing the tube
ends. Inspect to ensure tubes are free of scale and deposits.
If scaled, remove deposits with a stiff wire brush or mechanical
tube cleaner to bare metal. Reinstall return header casting.
Flush system.
Note: Removal of the heat exchanger is not required.
CAUTION
IF HEAT EXCHANGER MAINTENANCE REQUIRES TUBING
REPLACEMENT, SPECIAL PROVISIONS SHALL BE TAKEN TO
ENSURE THAT THE DAMAGED TUBES ARE CAREFULLY REMOVED.
REPLACEMENT TUBES MUST BE PROPERLY INSTALLED AND
EXPANDED INTO THE ROLLED TUBE TUB.
OVER-ROLLING, MISALIGNMENT OF TUBES OR IMPROPER
TIGHTENING OF THE ASSEMBLY MAY RESULT IN LEAKS OR
DAMAGE TO THE HEAT EXCHANGER. CONTACT YOUR
A. O. SMITH DEALER FOR DETAILED INSTRUCTIONS.
REPLACEMENT PARTS
Replacement parts may be ordered through A. O. Smith dealers,
authorized servicers or distributors. Refer to the Yellow Pages
for where to call or contact (in United States) the A. O. Smith
Water Products Company, 500 Tennessee Waltz Parkway,
Ashland City, TN 37015, 1-800-433-2545 or (in Canada)
A. O. Smith Enterprises Ltd., 768 Erie Street, Stratford,
Ontario, Canada N5A 6T3, 519-271-5800. When ordering parts
be sure to state the quantity, part number and description of the item
including the complete model and serial number as it appears on the
product. Refer to the parts lists (P/N 212513-000) for more information.
For Technical Assistance call A. O. Smith Technical Information
Center at 1-800-527-1953.