20
7 .5
Loose flow regulators
The boiler includes additional flow regulators to be used depending
on the area where the product is installed.
BWC150 - fitted
Lemon green
15.0 l/min
4.0 ga
l/min
BWC150 - spares
Olive Green
13.0 l/min
3.4 ga
l/min
Gray
18.0 l/min
4.8 ga
l/min
BWC120 - fitted
Red
12.0 l/min
3.2 gal/min
BWC120 - spares
Blue
10.0 l/min
2.6 ga
l/min
Dark blue
16.0 l/min
4.2 ga
l/min
DHW FLOW RATE
Entering
Water
Leaving
Water
BWC150
Large Combi
BWC120
Small Combi
Notes:
°F
°F
GPM
GPM
58
125
3.9
3.30
10 CFR Appendix E to
Subpart B of Part 430 –
tested with the factory
fitted flow restrictor.
How to select the flow restrictor to be used inside the boiler.
The selection must be done according the average ground
temperature in the area of boiler installation (entering water
temperature) and the minimum required leaving temperature
(outlet temperature of domestic hot water).
Select the flow restrictor according the below formula [the first one
with value less or equal to the calculated value]
K/(X-Y)=
DHW FLOW RATE according 10 CFR Appendix E to
Subpart B of Part 430
K= 3.9x(125-58)= 261.3 for BWC150
K= 3.3x(125-58) = 221.1 for BWC120
X= Minimum leaving temperature required
Y= Entering temperature of your area (from the map below)
Example:
Entering temperature of your area (from the map below) = 42°F
Minimum leaving temperature required = 115 °F
Boiler model: BWC150
261.3/(115-42) = 3.6 GPM
➡
Select 3.4 GPM flow restrictor [the
first one with value less or equal to the calculated value]
7 .6
General piping information
9
CAUTION:
Use two wrenches when tightening water piping at
the boiler, using one wrench to prevent the boiler return line
or supply line from turning. Failure to support the boiler piping
connections to prevent them from turning could cause damage
to boiler components.
NOTICE:
The boiler control module uses temperature sensors
to provide both high limit protection and modulating temperature
control. The PCB also provides low water protection using a
water pressure sensor (minimum 6.5 psi (0.45 bar)). Some codes/
jurisdictions may require additional external controls for high limit
and/or low water cutoff protection.
7 .6 .1
Separate low water cutoff
A low water cutoff may be required by state local code or some
insurance companies. Check code requirements before installation
of the boiler. If required:
−
Use a low water cutoff designed for hydronic installations
− Follow low water cutoff manufacturer’s instructions.
A hot water boiler installed above the radiation level or as required
by the Authority having jurisdiction, must be provided with a low
water cutoff device either as part of the boiler or at the time of boiler
installation.
NOTICE:
The electronic low water cutoff located internally in the
boiler is below the lowest safe permissible water level established
by the boiler manufacturer.
7 .6 .2
Backflow preventer (heating only model)
Use a backflow preventer specifically designed for hydronic boiler
installations. This valve should be installed on the cold water fill
supply line per local codes.
7 .6 .3
Fitting the heating circuit supply and
return pipes
NOTICE
: To protect the en
tire heating system the manufacturer
recommends installing a Y-Strainer in the return circuit. When
connecting the boiler to an existing heating system this device is
recommended to be installed.
− Install shut-off valves immediately before and after the Y-Strainer
to enable the Y-Strainer to be cleaned.
− Install a fill valve and drain valve in the heating system supply
pipe if required.
− Also plumb the pressure relief valve to the drain system.
NOTICE:
When using oxygen-permeable pipes, e. g. for floor
heating systems, you must separate the system using heat
exchangers.
− Thoroughly flush all pipes and radiators.
− Refer to the installation wall template for the pipe connection
dimensions.
− Connect the pipes so that they are free from strain.
7 .6 .4
Sizing space heat system piping
Size the piping and components in the space heating system using
recognized design methods.
Verify the 2.3 gal (9l) expansion tank is large enough for the
application. Some applications, such as base-board heating, may
require an additional expansion tank.
NOTICE:
The boiler, when used in connection with a refrigeration
system, must be installed so the chilled medium is piped in parallel
with the boiler and with appropriate valves to prevent the chilled
medium from entering the boiler.
NOTICE: The boiler piping system of a hot water boiler connected
to heating coils, located in air handling units, where they may
be exposed to refrigerated air circulation must be equipped with
flow control valves or other automatic means to prevent gravity
circulation of the boiler water during the cooling cycle.
7 .6 .5
Available Pump Head (ft. hd.)
The boiler is designed for closed loop, forced circulation hot water
heating systems only.
The boiler is equipped with an internal pump.
PUMP DUTY
Residual head of circulator
The residual head for the heating system is represented in the
graph, according to the flow rate. The piping on the heating system
must be sized taking into account the available residual head value.
Bear in mind that the boiler will operate correctly if there is sufficient
water circulation in the heat exchanger, as the boiler is equipped
with an automatic internal by-pass which is designed to ensure
water flow rate into the heat exchanger is correct under any
installation conditions.
9
CAUTION:
BWHAAG000120
and
BWHAAG000150
must not
be operated as a potable Hot Water Boiler.
BWCAAG000120
and
BWCAAG000150
must not be operated in an open
system.
