3 flue and ventilation, 4 installation – Glow-worm Inset 40BBU User Manual

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221722B

3 Flue and Ventilation

3.4 Precast Flue

The appliance is suitable for fitting to a properly constructed
non-impeded precast flue.

Note: It is not recommended that this boiler is fitted to a pre-cast
flue where plaster/rendering has been applied directly on to the
face of the flue block as this could lead to high surface
temperature and cracking of the plaster.

There must be a minimum vertical effective height of 3metres.

The flue cross sectional area must not be less than
198mmx97mm.

It is essential that the correct recess blocks, cover block and
offset blocks suitable for back boiler units have been used.

A sealed connection must always be made between the boiler
socket and the precast flue.

Note: It is possible, if this is a replacement, that the previous
appliance may have been more tolerant in respect of flue
requirements.

It is essential, therefore, as for ALL installations to make sure
that there is no spillage of the products of combustion from this
new appliance.

3.5 Ventilation - Back Boiler and Fire

The room in which the back boiler unit is installed must have
adequate air inlets to ensure correct operation as specified in
the current issue of BS5440 Part 2.

Ventilation requirement for the BBU 40 is 66cm

(11in

This ventilation area takes into account the total requirement of
the back boiler unit and fire.

The ventilation openings may be direct to the outside air or with
an internal room or space (such as a hall) which itself has a
permanent air vent of the same effective area. The permanent
air vent should be in a position which will cause the least
nuisance to occupants, due to draughts.

This vent MUST NOT be placed in the builder’s opening.

If the appliance is to be installed in a room already containing
another fuel burning unit, the air supply required for this other
unit MUST be added to the figure above.

Any air vent taken through a cavity wall must be ducted.

3.6 Extract Fans

If an extract fan is fitted in the premises, there is a possibility that
if adequate air inlet openings are not provided spillage of the
products of combustion could occur.

When openings are fitted in accordance with the
recommendations of the current issue of BS5440 Part 2, extract
fans should not cause spillage.

Where such a fan installation is found, a clearance of products
test must be conducted as described in the fire front Installation
Instructions, Section 4.5.

This test must be carried out with the back boiler fitted with its
fire front.

See also Section 6.3 of these instructions.

Note: Refer again to Section 1.7 and diagram 1.2 and make
sure that there is sufficient depth for the back boiler unit.

4 Installation

4.1 Preparation

Remove draught diverter, flueway baffles and fittings pack from
carton.

Check contents of fittings pack against packed list.

Remove back boiler body assembly from carton.

4.2 Water Connections

IT IS EXTREMELY IMPORTANT THAT NO SERVICE PIPES
ARE ROUTED IN FRONT OF THE BOILER. If the builder’s
opening was previously used for solid fuel all pipework within
should be protected with PVC tape or equal. Pipework passing
through walls of the opening should be sleeved and made good.

The two heat exchanger connections are supplied in the fittings
pack and MUST be used, see diagram 4.1.

IMPORTANT: Make sure that the return pipe assembly is
fitted the correct way, that is, the brazed joint must be
positioned downward into the heat exchanger - remove
label before fitting - see diagrams 4.1 and 4.4.

NOTE: Take care when soldering the copper connections not to
damage the fibre washers.

4.3 Pumped Heating with Gravity Domestic
Hot Water

NOTE: The draught diverter and capillaries are shown to aid
plumbing, but would not be fitted at this stage.

All pipework must comply with the current issue of BS5546.

The domestic hot water flow and return pipes must be 28mm.

Refer to diagram 1.4 for a diagrammatic layout.

If it is necessary to route pipework from both sides of the
builder’s opening, it is recommended that the heat exchanger is
positioned on the combustion chamber so that the gravity
circuits exit on the same side as the boiler connections.

If the heat exchanger connections are opposite hand to that
required, the heat exchanger can be turned, as follows, remove
the four screws securing the heat exchanger to combustion
chamber, see diagram 4.2. Turn heat exchanger, refit the four
screws.

It is recommended that pumped heating connections are pre-
piped as in diagram 4.4.

Note: The diagram 4.4 shows two methods “A” and “B” of
plumbing the flow pipe.

The central heating return must have the injector fitted on both
methods “A” and “B”, see diagram 4.4 for fitting the injector.

4.4 Pumped Heating and Hot Water

NOTE: The draught diverter and capillaries are shown to aid
plumbing, but would not be fitted at this stage.

Refer to diagram 1.5 for a diagrammatic layout.

If it is necessary to route pipework from both sides of the
builder’s opening it is recommended that the heat exchanger is
positioned on the combustion chamber such that the flow pipe
exits on the same side as the boiler connections.

It is recommended that the pumped return is pre-piped as in
diagram 4.3.