Constant volume direct fired make up air heaters to provide a fixed rate of heated fresh air to the space.
The units are ideal for supplying heating and make up air to large areas or to individual spray booths etc, where constant extract rates are used.
Generally units are sized to introduce slightly more make up air into the space than the extract air volume. A balanced amount of make up air can provide a slight positive pressure to distribute the air uniformly throughout the building and eliminate random air infiltration.
For special applications such as kitchen make up air and certain industrial processes where the transfer of odours or dust etc to surrounding areas needs to be avoided, the volume of make up air supplied is lower than the extract rate.