Flue System; Design Waste Gas Volume And Temperature; Flue Condensation; Disconnection - Hamworthy Purewell Installation, Commisioning And Maintenance Instructions

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.
Figure No. 3 - Gas Valve leak check procedure
Note: - Main gas supply pressure; G20 – 20mbar

6.0 FLUE SYSTEM

Detailed recommendations for flue systems are given in
BS 6644, British Gas Publication IM/11, "Flues for
Commercial and Industrial Gas-Fired Boilers and Air
Heaters".
The following notes are intended to give general guidance
only.

6.1 General Requirements

The Hamworthy Purewell series of boilers are designed
to be used with natural draught flues. Flue systems
should be designed in accordance
HAMWORTHY HEATING LTD.
G31 – 37mbar
5
PUREWELL AUTOMATIC IGNITION
with current regulations and with reference to the British
Gas publication IM/11 "Flues for Commercial and
Industrial Gas Fired Boilers and Air Heaters". The
following points should be noted: -
1) Each boiler MUST have its correct draught diverter
fitted in an unmodified condition before connection to
the flue system.
2) The bottom of the flue header should be at least 500
mm above the draught diverter skirt bottom.
3) The flue system must be self-supporting in the correct
position to avoid compression of the draught diverter
and enable its removal for boiler cleaning.
4) Boilers should be located as near the chimney as
possible the nearest being not more than 2m (6ft) away.
5) The flue system should be designed to achieve a
negative suction at all times at the draught diverter outlet
on all modules in a bank. For optimum performance,
draught conditions should be between -0.05 to -0.125
mbar. In the case of a single boiler installation the
minimum vertical flue height is 2m above the draught
diverter skirt. For multiple boiler installations consult
Hamworthy Heating Technical Department. In some
instances, mechanical assistance may be necessary.
The boilers are suitable for connection to a fan diluted
flue system, refer to British Gas publication IM/11 "Flues
for Commercial and Industrial Gas Fired Boilers and
Air Heaters".
6) Purewell boilers are suitable for installation in a
balanced compartment in accordance with the
requirements of BS 6644. Consult Hamworthy Heating
Technical Department for help or assistance if in doubt.

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 No. 1.

6.3 Flue Condensation

Care should be taken to ensure that the flue is installed
in such a way that any condensation produced on start
up will drain away naturally.

6.4 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.

6.5 Disconnection

Draught diverter models are designed to enable the
primary flue to be lifted clear of the boiler to ease
disconnection. The flue must be correctly reconnected
when servicing is complete ensuring locating bolts are
securely fitted. See Section 13: SERVICING for further
information.
500001035/G