HAMWORTHY HEATING LTD
WESSEX-HE 200 BOILER
500001008/K
5
4) Close D and monitor the manometer over a 2
minute period * - a rise would indicate a leak on valve
D.
To Check Valves A, B & C.
1) Repeat using main gas supply pressure between
A, B, C & D.
System A, B, C, D may be considered sound if over a
period of 2 minutes any pressure drop is less than 0.5
mbar.
* NOTE:
Allow a manometer stabilisation period of
approximately 1-minute before each 2 minute check
period.
Following soundness tests, remove manometer
connections and tighten test point TP1.
NOTE:
Care must be taken not to allow soapy water
on or near any electrical parts or connections.
Figure No. 1 - Gas Valve Leak Check Procedure
Key: -
I - PILOT GAS BURNER
II - MAIN GAS BURNER
III - APPLIANCE ISOLATING VALVE
IV - MAIN GAS SUPPLY =
NATURAL GAS
(G20) - 20mbar
PROPANE
(G31)
-
37mbar
V - MANOMETER
6.0 FLUE SYSTEM
Detailed recommendations for flue systems are given
in
BS 6644
and Institution of Gas Engineers
Publication
UP/10
“Installation of gas appliances in
industrial and commercial premises Part 1: Flued
appliances”.
The following notes are intended to give general
guidance only.
6.1 Suction
The flue system should be designed to maintain
atmospheric pressure or a slight suction at the boiler
flue connection at all times. It is recommended that a
draught stabiliser is fitted to the flue system where the
suction is likely to exceed 0.1mbar or the height of the
flue exceeds 4metres.
6.2 Exhaust Gas Volume and Temperatures
The volumes, etc. relating to Propane firing can be
found in Appendix ‘A’.
It is recommended that the volume and temperature
of the waste gases shown in Table 2.2 are used for
the design of the flue system.
6.3 Flue Condensation
Due to the high thermal efficiency of the boiler, the
flue gas temperature is approx.125°C. Condensation
in the flue is thus more likely 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 2½° upwards in the direction of
exhaust gas flow (no horizontal sections). All joints
should be such that any condensation is directed
back down the slope. The drain fitted to the Wessex
200 HE boiler casing is 22mm O/D (16mm I/D) and
will take an appropriate compression fitting (The
County has a Rc¾ socket connection). It will
adequately cope with condensation from 6 metres of
twin-wall flue, any longer lengths of flue should have
separate open drain connections. The drainpipe
must be manufactured from a non-corrosive material
and be at least 15.0mm dia. It must also have a fall of
at least 3°(approx. 50mm per metre) and connect to a
drain via a waste trap.
6.4 Materials
Materials used for the flue system must be asbestos
free, mechanically robust, resistant to internal and
external corrosion, non-combustible and durable
under the conditions to which they are likely to be
subjected.
