CHAFFOTEAUX Flexiflame 280, Flexiflame 420 Installation Maintenance And Operating Instructions
Flexiflame
280 & 420 WT
Installation,Maintenance
and
Operating Instructions
The installation of these boilers must be carried out by a competent person
INTRODUCTION
The Flexiflame 280 and 420 are developments of the widely used Flexiflame 140 and comprise two or three standard boiler assemblies connected together in one casing.
The boiler assemblies (modules), each with an output of
41 kW (140,000 Btu/h), are mounted vertically above each
other providing high output to floor space and high output
to weight ratios.
The Flexiflame 280 and 420 are supplied with flanged water and gas connections to allow the simple connection of
second or subsequent boilers. Each boiler has an integral
common flue and is contained in a pre-assembled case
that permits easy access for installation and maintenance.
1. Steel chassis.
2. Aluminium flue duct.
3. Copper finned tube heat exchan-
ger.
4. Steel, dry wall, lined, combustion
chamber.
5. Gas section. ON/OFF with two
stage gas valve for quiet and stable
ignition.
6. Water section. Differential pressure, water section assures gas valve
cannot open until pump (IO) is operating.
7. Flame spillage overheat thermostat.
8. Flow isolating valve.
9. Return isolating valve.
10. Grundfos pump.
11. High temperature overheat thermostat.
12. Stainless steel all gas burner with
permanent pilot and thermo-electric
valve flame failure protection.
13. Piezo ignitor.
14. Levelling bolts.
15. Boiler thermostat and electrical
connection box.
16. Flanged gas header.
17. Flanged water monotube (insula-
ted).
18. Double pole isolating switches for
each module.
19. Fuses for each module.
20. Built in draught diverter. (Fitted
on Flexiflame 280 supplied separate
with the Flexiflame 420.)
DESCRIPTION
Fig. 1
Please note - If side panels are required to complete an installation, please consult installation instructions section 4 before
ordering boilers.
INSTALLATION AND OPERATING FEATURES
The Flexiflame 28C and 420 are designed to be used in
installations where space for plant accomodation is limi-
ted, and where modulating output is a requirement. Three
features distinguish these boilers from others of compara-
ble output.
Compact Construction - The materials and methods of
construction produce the following output to floor space
ratios.
CORVEC Flexiflame 280 - equivalent to 268 kW/m2
CORVEC Flexiflame 420 - equivalent to 399 kW/m2
These ratios will be of particular significance where existing plant rooms are required to provide higher output,
and where roof top installations are under consideration.
System design - The use of a unique monotube water
flow arrangement obviates the need to include boiler resistance in pump sizing. Each module is provided with a
pump to overcome the resistance of the associated heat
exchanger. The modules are connected in parallel to a
single water flow pipe (monotube) flanged at each end for
simple connection to the system or additional boilers. This
arrangement simplifies design, particularly in changeover
installations where existing pump sizes may not be
known. The boilers must be used with indirect systems
and should only be used in multiples. The 280 should not
be less than 2 off and the 420 not less than 3 off.
Controls-The boilers are fitted with simple controls suita-
ble for use in a wide variety of applications. On/off control
2
of modules is by starting and stopping the associated
pump either under the influence of the boiler thermostat or
an external control signal. Each boiler is fitted with a variable setting thermostat that brings modules under fire at
1 OC intervals. Where more than one boiler is installed,
continuous sequencing of modules can be effected, either
by using boiler thermostats or by using an external signal
from a step controller. Each module also includes a water
stopping device that prevents unnecessary water circulation through unfired modules.
The boilers are arranged in series to provide increments
of temperature rise to match variations in load and hence
return water temperatures. The boilers are designed for a
system temperature drop of 20 OC (36 OF), but the monotube arrangement provides a built-in by pass feature for
temperature differences of less than 20 oC. Figures 3 and
4 show a typical boiler arrangement and a schematic
layout of a single boiler.
The Flexiflame 280 & 420 boilers must only be used with
indirect fully pumped systems.
The system circulating pump should be sized relative to
the resistance of the connected load and the system design At selected. The mass flow rate through the monotube
should not be less than 0.6 I/s (8.1 gpm) per module and
the temperature difference across the monotube should
not be greater than 20” C.
Example :
2 x model 280 = 4 modules = minimum flow rate through
the monotube of 2.45 I/s (32.4 gpm)
2 x model 420 = 6 modules = minimum flow rate through
the monotube of 3.68 I/s (48.6 gpm).
DIMENSIONS
Fig. 2
c
9
A 1640 64.5 2142
84.3
8 711 28 711 28
C 430 16.9
430 16.9
0 1410 55.6 1912 75.2
E 1268 49.2 1110 69.7
F
250 10 250 10
G 260 10.25 260 10.25
H 112 4.4 112 4.4
J
305
12.0
305 12.0
K
160 6.3 160 6.3
Flexiflame 280
mm ins
Flexiflame 420
mm
ins
EXAMPLE OF BOILER ARRANGEMENT
Flange ‘Flange
CHLOOS/OlO Gasket
CHLOOS/OlO
CHLi07 Flange dHL 008
---mfomm
Fig. 3
Fig. 4
3
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