Inline inducers that can boost the draft or exhaust in chimneys serving process equipment, boilers and water heaters have been developed by Tjernlund Products, White Bear Lake, Minn. The most common reasons for installing inducers are ensuring negative draft, compensating for downdrafts, and coping with negative pressures, undersized flues or long horizontal vent connectors.

Inducers are available for inputs from 25,000 to 5,300,000 BTU/hr. Typical accessories include a universal control and fan-proving switch that interlocks with burner circuits. LED status/diagnostics simplify new installations and service calls.