Hamworthy Purewell VariHeat 70c, Installation, Commissioning And Servicing Instructions

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HAMWORTHY HEATING LTD
7
PUREWELL Vari
Heat c
500001169/T
4.3 Flues

Flue termination, routing and construction must comply with the requirements of the
Clean Air Act 1993—Chimney Memorandum, BS 6644 BS 5440 and IGE/UP/10.

Any flue must be self supporting and separable from the boiler for servicing
requirements.

The maximum number of modules firing into a common chimney is 9. For larger
installations refer to HHL Technical.

Due to the low flue gas temperature, 50°C (condensing) - 75°C (non-condensing),
condensation will occur in the flue, flue materials must be non-corrosive and utilise fully
sealing joints.

Flue construction is recommended of a twin wall, insulated type to maintain buoyancy
within the flue.

Adequate facilities must be provided for draining the flue condensation.

Horizontal flue runs must be kept as short as possible and be inclined at minimum 2°
towards the termination.

The flue system must be designed acknowledging that there may be a positive pressure
generated by the boiler combustion fan. Refer to Appendix C.

The flue system must be designed to limit the max. suction (cold) to 30Pa negative,
measured at the connection to the boiler. If the suction is greater than 30Pa, refer to HHL
Technical.

This condition must then be checked hot and with all boilers firing, the max.
pressure at the connection to the boiler should be 100Pa positive.
In the event that the flue system when hot does generate a suction, the max. suction
is 100Pa.

Any stabiliser fitted must be in or close to the vertical chimney.

Fan dilution - the design must provide for the use of balancing and trim dampers,
and their location and operation must be such that the constraints detailed above
can be met. Care must be taken to ensure that the fan performance is matched to
deliver the appropriate dilution, whilst ensuring that the excessive suction is not
applied to the boilers. If in doubt, refer to HHL Technical.

Fan assist - the use of fan assist must only be a last resort, as the boilers have
sufficient fan performance to drive the system. If in doubt, refer to HHL Technical.

Connecting flue systems may be smaller in internal diameter than the boiler
connection and must be designed to deliver the necessary condition at the
connection to the boiler. Refer to Hamworthy Heating Technical dept. for
assistance.