Water Line Connections; Thermostatic Point-Of-Use Mixing Valves - A.O. Smith 100 Series Installation And Operating Manual

DO NOT install any external condensate trap. The exhaust elbow
assembly has an internal condensate trap.
• Care should be taken to ensure there is no kink or twist in the
condensate hose.
• Condensate hose must be free and clear of debris and must not
allow back flow through drain line.
• Condensate must be able to flow freely to an appropriate drain.
• Do not allow condensate hose to become crimped closed.
• The condensate drain hose must not be elevated above the
connection on the condensate trap.
• Condensate from this water heater is mildly acidic (pH levels
between 4.3 and 5.0). Please note that some local codes
require that condensate be treated by using a pH neutralizing
filter prior to disposal. Condensate neutralizer kits are available.
Contact your distributor or Service Agency.

WATER LINE CONNECTIONS

To reduce the risk of unusually hot water reaching the fixtures
in the house, install Thermostatic Mixing Valves at each point-
of-use.
The water piping installation must conform to these instructions and
to all local and national code authority having jurisdiction. Good
practice requires that all heavy piping be supported.
Read and observe all requirements in the following sections before
installation of the water piping begins:

Thermostatic Point-of-Use Mixing Valves.

1.
Temperature-Pressure Relief Valve (page 31).
2.
Closed Water Systems and Thermal Expansion (page 30).
3.
THERMOSTATIC POINT-OF-USE MIXING VALVES
DANGER
HOT
HOT
BURN
Water temperature over 52°C
(125°F) can cause severe
burns instantly resulting in
severe injury or death.
Children, the elderly and the
disabled are at highest risk
of scald injury.
Feel water before bathing or
showering.
Temperature limiting devices
such as mixing valves must
be installed when required
by codes and to ensure safe
temperatures at fixtures.
Figure 35. Thermostatic Point of Use Mixing Valve
DANGER
HOT
HOT
BURN
Water heated to a temperature which satisfies space heating, clothes
washing, dish washing, and other sanitizing needs can scald and
cause permanent injury upon contact. Short repeated heating cycles
caused by small hot-water uses can cause a temperature increase
of the hot water above the heater's temperature settings.
In addition to using lowest possible temperature setting that
satisfies demand of application, to reduce the risk of scalding, install
Thermostatic Mixing Valves (temperature limiting valves) at each
point-of-use. See Figure 35 (page 29).
These valves automatically mix hot and cold water to limit the
temperature at the tap. Thermostatic Mixing Valves are available
from your local plumbing supplier. Consult a Qualified Installer or
Service Agency. Follow mixing valve manufacturer's instructions for
installation of the valves. Before changing the factory setting on the
control system, see Temperature Regulation (page 38).
If you choose a higher temperature setting, Thermostatic Mixing
Valves located at each point-of-use are particularly important to help
avoid scalding. See Figure 35.
Some people are more likely to be permanently injured by hot
water than others. These include the elderly, children, the infirm
and the physically/mentally disabled. Table 17 (published by U.S.
Government Memorandum, 1978) shows the approximate time-to-
burn relationship for normal adult skin. If anyone using hot water
provided by the water heater being installed fits into one of these
groups, special precautions must be taken.
In all cases, the following burn table must be used.
29
Water temperature over
125°F can cause severe
burns instantly resulting in
severe injury or death.
Children, the elderly and the
disabled are at highest risk
of scald injury.
Feel water before bathing or
showering.
Temperature limiting valves
are available.
Read instruction manual for
safe temperature setting.