16
FUTERA FUSION INSTALLATION AND OPERATION INSTRUCTIONS
DOMESTIC WATER SUPPLY PIPING
CAUTION: Proper controls 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.
Bleed Air From Boiler
Open the water heater piping bleed valves one at a time,
to purge the air trapped in the primary and secondary heat
exchangers. Refer to piping drawings (Figures 12 & 13) for
bleed locations.
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 corrosion 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.
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 flow rate through
a Futera Fusion water heater is 97 GPM,
6.1 L/s
on 500
through 1000 models and 136 GPM,
8.9 L/s
for 1250 through
2000 models. The cupro-nickel heat exchanger allows for
108 GPM,
6.8 L/s
on 500 through 1000 models and
151 GPM,
9.5 L/s
on 1250 through 2000 models.
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
selections. If local water conditions are extreme, follow the
guidelines in the Heat Exchanger Selection Table (Table
8A). 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.
Expansion Tank
An expansion tank or other means to control thermal
expansion must be installed in the water heating system if
back fl ow prevention devices are installed.
Pump Requirements
This low-mass water heater requires a continuous mini-
mum water fl ow for proper operation. The proper velocity
through the water heater must be maintained in accordance
with Table 7 for effi cient operation and long life. If the
temperature rise through the water heater is lower than
recommended the water velocity is too high. Premature
erosion of the heat exchanger will occur. Conversely, if the
temperature rise is higher than recommended in Table 7
the fl ow rate is too low. Scaling and softening of the heat
exchanger will occur.
The temperature rise across the
water heater must never exceed 35°F,
19.4°C
.
Storage Tank Thermostatic Mixing Valve – Water
Above 140˚F
,
60˚C
Water can be stored at temperatures
above
140˚F
,
60˚C
provided that a thermostatically
controlled mixing valve is used to temper the hot water to
an acceptable temperature before it’s supplied for domestic
use.
The mixing valve MUST be set to prevent a scald injury
from occurring, see the caution against scalding.
Storage of water for domestic use above
140°F
,
60°C
will
provide an increased quantity of tempered water and help
prevent the growth of water born bacteria.
