Installation Manual
whl-007 Rev. 1.14.15
8
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.
G. Potable Expansion Tank
A potable hot water expansion tank may be required to oset
heated water expansion. If there is a back ow 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 ow rate must meet the requirements
found in the water heater specications, Part 2, this manual,
or the published ratings cannot be achieved. The ow chart
below represents the pipe run, water heater, and heat
exchanger ONLY and does not include any ow checks, zone
valves, or friction loss through the boiler. That resistance must
be added to the value found in the following chart.
Table 3 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.
Figure 3 - Pressure Drop through the Heat Exchanger