This is generally an electrical heater. When the skin air gets to around six*c (forty two.8F) the heater will arrive on and heat the air up to guard the components within from frost. In any other case This may freeze the heating and cooling coils inside and burst them. As https://air-handling-units-ahus94825.blogthisbiz.com/38366277/a-simple-key-for-air-handling-unit-ahu-hire-unveiled