joule HHH-AEHP-00001, Installation & Maintenance Manual

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Connecting to the ventilation ductwork
Ductwork – Extract Air
Ductwork – Exhaust Air
The ventilation ductwork system is essential to the performance of an Exhaust Air Heat Pump. To avoid
under performance of the Heat Pump or increased system noise, the following points should be considered
when designing/ installing the ductwork:
• Avoid sharp bends or transitions.
• Swept 90° bends or 2x45° bends are preferred.
• Use two 45° bends instead of one 90° bend
• Ensure all burrs are removed from duct ends.
• Insulated flexible ducts must be used to connect the ductwork to the Heat Pump.
• Ensure all joints and connections are sealed appropriately
• The maximum pressure drop across the external grille of the exhaust duct shall not exceed 8 Pa.
• The maximum permissible pressure drop for the entire duct system shall not exceed 150 Pa (excluding
the Heat Pump).
• The pressure drop across the Heat Pump is 30 Pa
The Extract Air or ‘Air In’ to the Heat Pump is the heat source to
the Exhaust Air Heat Pump system. The extract air is fed via the
ductwork to the Heat Pump from all wet rooms within the dwelling.
The Exhaust Air or ‘Air Out’ from the Heat Pump is the exhaust of the
cooled air from the Heat Pump to outside the dwelling. It is essential
this duct is insulated as the average temperature in the duct will be
4°C under normal operating conditions. When the duct passes
through ceiling voids, condensation on the outside of the duct will
occur. To avoid this, the entire exhaust duct must be insulated with
suitably sized insulation, to local building regulations. The exhaust
ducting from the unit should be connected to the roof/wall terminal
using a suitably insulated adapter and grill.
The exhaust ducting should be no less than Ø150mm or 220mm x
90mm flat pack. It is necessary to adhere to this duct specification
to comply with noise specifications and to prevent potential
condensation. 220mm x 90mm flat pack ducting must terminate
with a double air brick.
Ductwork insulation MUST be fully sealed at all joints,
transitions, air bricks and/or roof cowls.