Espar air heater ducting size

• D2, S2, D2L, AS3 D2L, AS3 B2L heaters use only 60 mm ducting. The duct size cannot be increased.

• D4, B4, M2 D4L, M2 B4L, AM3 D4L, AM3 B4L heaters can use 90 mm or 75 mm ducting, but the initial ducting must be 90 mm. Using 60 mm ducting on a 4 kW heater can cause heat reflection and reduced performance.