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Finned copper tube gas boilers & water heaters – Boiler Manual
12
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Flow Switch
Th e fl ow switch supplied with the boiler/water heater must be
wired to the terminal strip in the control panel to prevent the boiler
from fi ring unless there’s adequate water fl ow through the unit. Th e
fl ow switch must be installed in the supply piping adjacent to the
boiler outlet connection.
Failure to properly install the fl ow switch may result
in damage to the boiler/water heater heat exchanger
voiding the warranty!
HEATING SYSTEM PIPING
General Piping Requirements
All heating system piping must be installed by a qualifi ed technician
in accordance with the latest revision of the ANSI/ASME Boiler and
Pressure Vessel Code, Section IV, and ANSI/ASME CSD-1,
Standard for Controls and Safety Devices for Automatically Fired
Boilers. All applicable local codes and ordinances must also be
followed. A minimum clearance of
1 in
,
25 mm
must be maintained
between heating system pipes and all combustible construction.
All heating system piping must be supported by suitable hangers
not the boiler. Th e thermal expansion of the system must be
considered when supporting the system. A minimum system
pressure of
12 psig
,
82.7 kPa
must be maintained.
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 9, 10 & 11) for bleed locations.
Heating Boiler Piping Connections
Th e supply and return connections should be sized to suit the system,
see Table 7.
Table 7
Supply & Return Pipe Sizing
Model Size
Supply Size
Return Size
500 thru 1000
2” NPT
2” NPT
1250 thru 2000
2 1/2” NPT
2 1/2” NPT
Pump Requirements
Th is low mass boiler requires a continuous minimum water fl ow
for proper operation. Th e boiler pump is sized to overcome the
head loss of the boiler and the near piping in order to achieve the
required temperature rise. Th e temperature rise across the boiler
must never exceed
35°F
,
19.4°C
. Th e adjustable pump delay turns
the pump on each time the burner fi res and runs the pump for 20
to 600 seconds aft er the call for heat is satisfi ed.
Th e maximum allowable primary heat exchanger
temperature rise is
35°F
,
19.4°C
.
Th
e maximum allowable fl ow rate through a Futera Fusion boiler
is 97 GPM,
6.1 L/s
on 500 through 1000 models and 136 GPM,
8.6 L/s
for 1250 through 2000 models. Th
e 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.
Factory Supplied - On Board - Circulating Pump
Th e factory installed - on board - pump is sized to work the total
boiler head loss plus an additional (30 ft ) of pipe and (6 elbows)
- (min pipe diameter of inlet/outlet boiler water connections - see
Table 7). Please consult factory for systems outside these parameters.
Low Water Cutoff
If a boiler is installed above any radiation elements it must be fi tt ed
with a low water cutoff device.
Refer to the wiring diagram supplied with the boiler/water heater
for proper wiring connections.
Expansion Tank & Air Separator
An expansion tank or other means to control thermal expansion
must be installed in the heating system. An expansion tank must
be installed close to the boiler on the suction side of the pump. An
air scoop and automatic air vent must also be installed to eliminate
air trapped in the system.
Primary/Secondary Piping
Figure 10 shows a typical primary/secondary piping system. Boilers
connected to heating systems using zone valves, zone pumps, or
systems that have excessive fl ow rates must be isolated from these
systems to protect the boiler.
Multiple Boiler Systems
Systems using multiple boilers can also be installed using a primary/
secondary manifold system, Figure 11.
Piping For Use With Cooling Units
Th e boiler, when used in connection with a refrigeration system,
must be installed so the chilled medium is piped in parallel with
the boiler. Appropriate valves must be used to prevent the chilled
water from entering the boiler.
When a boiler is connected to a heating coil that may be exposed
to refrigerated air from an air handling device, the piping system
must be equipped with fl ow-control valves or some other automatic
means of preventing gravity circulation of the boiler water during
the cooling cycle.
