lp-451 Rev. 001 Rel. 001 Date 7.25.17
7
RE-INSPECTION OF T&P RELIEF VALVES: T&P valves should be
inspected AT LEAST ONCE EVERY THREE YEARS, and replaced if
necessary,
by a licensed plumbing contractor or qualified service
technician to ensure that the product has not been affected by
corrosive water conditions and to ensure that the valve and
discharge line have not been altered or tampered with illegally.
Certain naturally occuring conditions may corrode the valve and
its components over time, rendering the valve inoperative. Such
conditions can only be detected if the valve and its components
are physically removed and inspected.
Do not attempt to
conduct an inspection on your own.
Contact your plumbing
contractor for a re-inspection to assure continued safety.
FAILURE TO RE-INSPECT THE T&P VALVE AS DIRECTED COULD
RESULT IN UNSAFE TEMPERATURE AND/OR PRESSURE BUILD-
UP WHICH CAN RESULT IN PROPERTY DAMAGE, SERIOUS
PERSONAL INJURY, OR DEATH.
F. Scalding
An ASSE 1017 or ASSE 1070 temperature limiting or mixing valve
is recommended in installations servicing disabled or elderly
persons, or children. Mixing valves do not eliminate the risk of
scalding.
To avoid scalding:
•
Set the water heater set point temperature as low as
possible.
•
Feel water before bathing or showering.
•
If thermostatic valves are required, use devices specifically
designed for such purpose. Install these devices in
accordance with instructions provided by the manufacturer.
Failure to install a temperature limiting or mixing valve and
follow these instructions could result in property damage, severe
personal injury, or death due to scalds.
This water heater can
deliver scalding water. Be
careful whenever using
hot water to avoid scalding
injury. Certain appliances
such as dishwashers and
automatic clothes washers
may require increased
water temperatures. By
setting the thermostat
on this heater to obtain
the increased water
temperature required by
these appliances you may
create the potential for
scald injury.
To protect against injury,
install a mixing valve in the
water system. This valve
will reduce point of use
discharge temperatures by
mixing cold and hot water
in branch supply lines.
Such valves are available from your local plumbing supplier.
Table 1 details the relationship of water temperature and time with
regard to scald injury and may be used as a guide in determining the
safest water temperature for your applications.
G. Potable Expansion Tank
A potable hot water expansion tank may be required to offset heated
water expansion. If there is a back flow preventer or any other type
of no return or check valve in the system a thermal expansion tank IS
MANDATORY. The expansion tank must be sized for the entire water
volume of the hot water system. A weeping relief valve indicates the
need for an expansion tank. See the Typical Expansion Tank example in
the Piping section for details.
H. Pressure Drop Sizing For Circulator
The boiler circulator flow rate must meet the requirements found in
the water heater specifications, Part 2, this manual, or the published
ratings cannot be achieved. The flow chart below represents the pipe
run, water heater, and heat exchanger ONLY and does not include
any flow checks, zone valves, or friction loss through the boiler. That
resistance must be added to the value found in the following chart.
Figure 3 - Pressure Drop through the Heat Exchanger