LAB1283R, Issue 2, Apr 2017
Page 3
10. In dwellings where it is intended to install open-flue appliances and extract ventilation, the
combustion appliance should be able to operate safely, whether or not the fans are running. A
way of showing compliance with The Building Regulations in these circumstances would be to
follow the installation guidance shown below, and to show by tests that combustion appliances
operate safely, whether or not the fans are running.
A. For gas appliances: where a room contains an open-flue appliance, the extract rate
should not exceed 20l/s (72m³/h).
B. For oil appliances: where a room contains an open-flue appliance, the extract rate
should be limited to 40l/s (144m³/h) for an appliance with a pressure jet burner and
20l/s (72m³/h) for an appliance with a vaporising burner.
C. For solid fuel appliances: avoid installing extract ventilation in the same room.
Further reference should be made to Approved Document J of the Building Regulations.
11. A condensate drain should be installed from the appliance to an appropriate drain location.
Domus recommend the Domus 297 dry- trap and condensate drain kit
.
12. The condensate drain and associated pipe work must be cleared of debris prior to
commissioning and insulated where it passes through unheated spaces and voids.
13. This appliance should not be connected to a tumble dryer or cooker hood.
14. The supply air must be drawn from the exterior of the property.
15. The extract air must be expelled to the exterior of the property.
16. It is recommended that the two external terminals or grilles are set at least 2m apart.
17. The supply and exhaust ceiling valves should be positioned at least 300mm from internal
walls to allow airflow measuring equipment to fit correctly over the valves.
18. All ducting should be insulated with Domus Thermal duct insulation where it passes through
unheated spaces and voids (e.g. loft spaces) to reduce the possibility of condensation forming
and heat loss. Additionally, both ducts connecting the HRX2D to outside must be insulated to
avoid condensation forming on the outside of the ducts.
V E N T I L A T I O N
