RBI Boiler, Installation And Operation Instructions Manual

Page: 46 / 154

46
8.2.3 - Expansion Tank
If a water heater is installed in a
closed water supply system, such
as one having a back fl ow preventer
in the cold water supply line, means
shall be provided to control thermal
expansion. Contact the water supplier
or local plumbing inspector on how to
control this situation.
Install an expansion tank. Ensure
the expansion tank is properly sized
for the water volume (See Section
15, header “Content of water”) and
the system volume, temperature and
pressure.
CAUTION!!!
Undersized
expansion tanks will cause
system water to be lost
through the relief valve
The expansion tank must be located
as shown in Figures 8-5 and 8-6 or as
per recognized design methods. Refer
to the expansion tank manufacturer
instructions for additional installation
details.
8.2.4 - Circulator pump
This water heater must be fi tted with
a circulator pump for domestic hot
water. The water resistance of the
water heater is shown in graph form in
Figure 7-3. To this resistance installer
shall add the system water resistance
and the storage tank water resistance
to size the circulator pump to supply
fl ow through the storage tank.
To electrically connect the pump
(Local pump) follow Figure 10-5.
A fi eld supplied pump relay must be
installed if the pump current draw is
grater than 3 amps.
8.2.5 - Sizing water
system
Size the pump, piping and system
components required in the water
system, using recognized design
methods.
CAUTION!!!
It is up to the
installer to ensure the minimum
water heater fl ow is not less
than 4 GPM at any time. If
the fl ow is lower, the unit
automatically stops the burner.
8.3 - Scalding
This water heater can deliver scalding
temperature water at any faucet in the
system.
Be careful whenever using hot water
to avoid scalding injury.
Certain appliances such as
dishwashers and automatic clothes
washers may require increased
temperature water.
By setting the water temperature
control on this water heater to obtain
the increased temperature water
required by these appliances, you
may create the potential for scald
injury.
To protect against injury, you should
install a mixing valve in the water
system.
This valve will reduce point of
discharge temperature by mixing cold
and hot water in branch supply lines.
Such valves are available from the
local plumbing supplier.
Figure 8-1 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.
8.2.6 - Sizing storage
tank
Storage tank can be sized for two
DHW mode working:
a) - big storage for high peak
tapping fl ow requests.
In this case the storage must be
properly sized as per recognized
design method.
Water heater must be set to work with
a big storage as follow:
- Gain access to the Factory menu
(see section 19) and set parameter
3012 to 1;
- Connect water heater’s electrical
terminals as indicated on Figure 10-6
b) - small storage for instantaneous
tapping fl ow request.
In this case the storage must be
properly sized as per recognized
design method.
Water heater must be set to work with
a small storage that works like an
instantaneous heat exchanger:
- Gain access to the Factory menu
(see section 19) and set parameter
3012 to 0;
- Connect water heater’s electrical
terminals as indicated on Figure 10-5
8 - INSTALLATION - IW water connections