20
Cast Iron Condensing Boilers – Installation Manual
FlexCore Stainless Steel Condensing Boilers – Installation Manual
Flow Sensor
The factory mounted SIKA flow sensor, as shown in
Figure 9, is wired to prevent the boiler from firing unless
there's adequate water flow, Table 6, through the unit.
The SIKA flow sensor sends information to the
HeatNet control and displays the water flow
information in (gpm). The minimum flow settings
are fully adjustable. The boiler will not operate if the
(gpm) falls below the minimum value. If the system
is using Glycol the % of glycol mixture must be
entered. The SIKA Flow sensor is limited to
194°F, 90°C water temperature, 145 psi operating
pressure and a 50% glycol mixture. If the return
water temperature rises above
194°F, 90°C the
boiler will shut down. For applications outside
these requirements, please consult Manufacturer.
Reference the HeatNet IOM for menu instructions.
Air Vent
The factory mounted air vent, as shown in Figure 9, is
installed to automatically purge unwanted air from the
boiler allowing the system to run more effectively.
Please note that after installing in a new
system or retrofitting an old, close the isolation
valve installed upstream of the Air Vent prior
to filling the system with water. Once the
system has been properly filled open the Air
Vent isolation valve for automatic operation.
If this is not done, it is entirely possible that
the internal float mechanism will become
clogged open, causing the air vent to leak.
Table 6 - Temperature Rise Table
In order to maintain boiler capacity, increase
flow rates approximately (10%) and pump
head (25%) for mixtures up to 50% glycol.
Use the following equation to determine the
boiler derate capacity when adjustments aren't
made. (2012 ASHRAE Systems Handbook)
Model
Size
Water Flow Rates
(GPM)
100%-Input
20%-Input
Min. *
Max. *
Min.
0850
16.2
81.2
16.2
1000
19.1
95.5
19.1
1500
28.5
142.7
20.4
2000
38.0
190.2
25.4
2500
48.0
239.8
32.0
3000
58.1
290.5
38.7
3500
66.6
332.9
44.4
4000
76.1
380.4
50.7
4500
86.6
433.1
57.7
5000
95.9
479.7
64.0
6000
116.2
581.0
77.5
7000
134.2
670.9
89.4
8000
154.3
771.5
102.9
9000
174.3
871.5
116.2
*Min/Max flow correspond to a (20°F/100°F) Δt at full input, for
applications requiring operation above and/or below these parameters,
please consult manufacturer.
qw = 500*Q*(p/pw)*Cp*
Δ
T
Where
qw = Total heat transfer rate, BTU/h Q = flow rate, gpm
p = fluid density. lb/ft³
pw = density of water at 60°F, lb/ft³
Cp = specific heat of fluid, Btu/lb °F
Δ
T = temperature difference, °F
HEATING SYSTEM PIPING
General Piping Requirements
All heating system piping must be installed by a qualified
technician in accordance with the latest revision of the
ANSI/ASME Boiler and Pressure Vessel Code, Section IV.
Where required, the piping must comply with 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
1in, 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. The
thermal expansion of the system must be considered
when supporting the system. A minimum system
pressure of
20 psig, 138 kPa must be maintained at
boiler operating conditions. For glycol systems, a
minimum system pressure of
30 psig, 207 kPa must be
maintained at boiler operating conditions.
Boiler Piping Connections
The supply and return connections should be sized to
suit the system, see Table 7.
Table 7 - Supply & Return Pipe Connection
System Cleaning & Flushing: Prior to
commissioning the boiler(s), the piping/
system must be cleaned and flushed to
prevent contaminants from settling back into
the boiler and fouling the heat exchanger.
Isolate the boiler from the system prior to the
cleaning process. Fill the system with water, add
the cleaning solution and follow the solution
manufacturer’s instructions. Once clean, refill
the system with clean water as specified in the
Water Treatment section.
Model Size
Supply Size
Return Size
0850
3" NPT
3" NPT
1000
3" NPT
3" NPT
1500
3" NPT
3" NPT
2000
3" NPT
3" NPT
2500
3" NPT
3" NPT
3000
3" NPT
3" NPT
3500
4" NPT
4" NPT
4000
4" NPT
4" NPT
4500
4" NPT
4" NPT
5000
4" NPT
4" NPT
6000
4" NPT
4" NPT
7000
6" NPT
6" NPT
8000
6" NPT
6" NPT
9000
6" NPT
6" NPT
