Heating Circuits; Domestic Water (Hot Water Tank); Return Temperature; Accumulator Tank - Baxi Bioflo Installation & Servicing Instructions Manual

For the Installer
Circulation pump
(installed as standard in FireWIN versions UAM and UAML)
The circulation pump shaft is lubricated by water, therefore the pump is never allowed to run without water.
Model: HUP 15–4.0 U
Installation dimension: 130 mm
Diagram 1 Pump characteristic curve

2.7.2 Heating circuits

A motorised mixing valve is always required for the FireWIN in order to protect the boiler and one must be fit-
ted in each heating circuit. A feed contact thermostat (FK-001) must be installed for underfloor circuits. If required,
the hydraulic fittings can be integrated in the boiler for 1 mixed heating circuit (UAM or UAML version).

2.7.3 Domestic water (hot water tank)

If FireWIN is used for loading a hot water tank, a gravity brake must be installed in the heating return. This is
provided as standard with FireWIN UAML.

2.7.4 Return temperature

The return flow temperature increase installed as standard means that FireWIN can be operated with a return
temperature down to min. 20 °C. No external return flow temperature increase is required.

2.7.5 Accumulator tank

In principle a pellet boiler system does not need a buffer tank. A guaranteed minimum heat consumption is
required, e.g. fit a consumer circuit that cannot be blocked off or do not fit thermostat valves on all radiators.
Exceptions:
If the total heating requirements of the building according to the ÖNORM M 7500 or EN 12831 calculation are
less than 50 % of the boiler's nominal output, we would recommend integrating a buffer tank in the system.
This means that the FireWIN loads the buffer tank with a return hold-up group.
(Hydraulic system SYS 402, please contact Windhager for planning advice)
Boiler installation criteria:
– controlled residential area ventilation is an advantage if the boiler is being installed in a small space or if
building heat loads are low
– heat shield (accessory: FIRE 023) needed
– the room temperature in the installation room is too high
– FireWIN operating times are set by the system control
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