Domestic Water Supply Piping - RBI DOMINATOR Series Installation And Operation Manual

Page 18

DOMESTIC WATER SUPPLY PIPING

CAUTION: Proper control settings must be used to
prevent water supplied for domestic use from
exceeding 130°F, 54°C or a scald injury will occur!
When higher water temperatures are required for
appliances such as a dishwasher, a mixing valve or
some other tempering means must be installed.
Households with small children may require water
temperatures less than 120°F, 49°C. Local codes
must be complied with!
General Piping Requirements
Ensure that the water heater is equipped with bronze
headers. Piping and components connected to the water
heater must be suitable for use with potable water. The
water heater must not be connected to any heating
system piping or components previously used with a non-
potable water heating appliance. No toxic chemicals, such
as those used for boiler treatment, are to be introduced
into the potable water used for space heating. If a hot
water storage tank is used in the system it must be
equipped with a temperature and pressure relief valve
that complies with ANSI Z21.22 or CAN-4.4 and CAN-4.6.
NOTE: The storage tank must be located as close
to the water heater as possible to prevent excessive
head loss which will reduce fl ow.
Water Chemistry
The required temperature rise across the water heater
is based on water having a hardness between 8 and 18
grains per gallon with a level of dissolved solids not
exceeding 350 ppm. Water having a hardness less than
8 grains can cause excessive errosion of the heat
exchanger. Water that has a hardness greater than 18
grains per gallon and/or a level of dissolved solids
exceeding 350 ppm will require a recalculation of the
pump size and temperature rise.
DOMINATOR INSTALLATION AND OPERATION INSTRUCTIONS
A cupro-nickel heat exchanger may also be required. The
manufacturer should be consulted when these water
conditions are encountered. See Table 8A.
CAUTION: The maximum allowable fl ow rate through
a Dominator water heater with copper heat exchanger
is 105 GPM, 6.6 L/s. The cupro-nickel heat exchanger
allows for 120 GPM, 7.6 L/s, see Table 8B.
RBI water heaters are designed to run scale free. Due
to the extreme variables of water conditions world wide
it is necessary to consider pH values and water
hardness in relationship to scaling. It is crucial to
consider these two variables when making heat
exchanger and pump selection. If local water conditions
are extreme follow the guidelines in the Heat Exchanger
Selection Table (Table 8A) and the Pumping
Performance Table (Table 8B). Scale free operation can
be achieved by using water with a hardness between 8
and 18 and by maintaining the pH between 5 and 9.
Follow the conditions listed under NORMAL in the table.
In some areas of the country additional precautions
must be observed due to unusual characteristics of the
local water supply. Call the nearest RBI representative
for details.
To properly size the pump a grain hardness and pH test
must be taken at the installation site before the order is
placed. Proper pump sizing will improve heater
performance and help ensure heater longevity.