This is frequently an electrical heater. When the outside air receives to about six*c (42.8F) the heater will appear on and warmth the air up to safeguard the components inside from frost. Or else this could freeze the heating and cooling coils within and burst them. Modifiers that boost the https://andyqvzdi.blogacep.com/39326229/examine-this-report-on-air-handling-units-ahus