Flue System; General Requirements; Design Waste Gas Volume And Temperature; Materials - Hamworthy Wessex 100 M100 Installation, Commissioning And Servicing Instructions

Although the boiler receives a gas leak check and
gas train component integrity check prior to leaving
the factory, transport and installation may cause
disturbance to unions, fittings and gas valve
assemblies etc. During commissioning a further test
for soundness should be carried out on the boiler
gas pipework and components. A procedure guide
is given below refer to Figure 5.6. Care must be
taken not to allow leak detection fluid (if used) on or
near any electrical parts or connections.
Note: In the case of M200 & M300 appliances, the
test detailed should be carried out on the entire
assembly.
Figure 5.6 Gas valve/pipework leak test procedure.
Note: - Main gas supply pressure - G20 - 20mbar
To Check Valve B
1) Turn off the electrical power and gas to the
appliance.
2) Connect the manometer to gas valve test point.
3) With A, B closed open C and monitor manometer
over a 2 minute period, a rise indicates a leak on
valve B.
To Check Valve A
1) Open C.
2) Open B to produce the main gas supply pressure
between A and B.
3) Close B
4) System may be considered sound if over a period
of 2 minutes any drop in pressure is less than 0.5
mbar (0.2" wg.).
NOTE: Allow a manometer stabilisation period of
approximately 1-minute before each 2 minute check
period. Following soundness tests close valve B and
remove manometer connections and tighten test
points.
HAMWORTHY HEATING LTD
- G31 - 37mbar
7
WESSEX 100 M

6.0 FLUE SYSTEM

Detailed recommendations for flue systems are
given in BS 6644, I. Gas E. Publication IGE/UP/10
"Installation of gas appliances in industrial and
commercial premises Pt 1 flued appliances".
The following notes are intended to give general
guidance only.

6.1 General Requirements

The Hamworthy Wessex 100 M series of boilers are
designed to be used with natural draught flues. Flue
systems should be designed in accordance with
current regulations and with reference to the
BS6644 & IGE/UP/10. The following points should
be noted:-
Due to the high thermal efficiency of the boiler, the
flue gas temperature is approximately 130°C.
Condensation in the flue is thus more likely to occur
than with lower efficiency boilers. It is strongly
recommended that twin-wall or insulated flue pipe is
used on all installations. Care should be taken to
ensure that the flue is installed such that any
condensation is continuously drained. All flues
should have a minimum slope of 2° upwards in the
direction of the exhaust gas flow (no horizontal
sections). All joints should be such that any
condensation is directed back down the slope to an
open drain connection in the flue. The drain pipe
must be manufactured from a corrosion resistant
material and be at least 15mm dia. It must also have
a fall of at least 2-3° (approx. 3-5cm per metre) and
connect to a drain via a waste trap.
An alternative to a conventional flue system is the
Hamworthy Forston Fan Dilution system which is
suitable for connection to the Wessex range of
boilers. For further information contact Hamworthy
Heating Technical Department.

6.2 Design Waste Gas Volume and Temperature

It is recommended that the volume and temperature
of the waste gases used for design of the flue
system be as shown in Figure 2.2 (p4).

6.3 Materials

Materials used for the flue system must be
mechanically robust, resistant to internal and
external corrosion, non-combustible and durable
under the conditions to which they are likely to be
subjected.
Consideration should be given to possible freezing
of condense water traps and pipework. This must be
avoided at all times.
500001080/F