I have an ~ 1998 Coleman Evcon gas furnace in a mobile home. It has a "BlendAire II" system on it. Recently, an alarm went off which indicates a problem with the vent attic fan. Does anyone know what this does or what typically goes wrong with this ? From what I have read, there is a circuit board in the unit (I run on LP), a circuit board in the vent close to the roof, and a motor/fan that provides fresh air to the mobile home. When I called a local HVAC service guy, he said Coleman Evcon told him that you do not need the vent fan, and it was initially there to provide fresh air to the mobile home since they were thought to be so air tight, you may starve oxygen. Can anyone shed any light about why the vent fan in the blendaire system is there, and when this light goes off, typically is it a ckt board or fan motor?

Thanks for any help !

This site tells about trouble shooting with the blend air system--
We have had the same problem
Blend Air II System

90% of the mobile homes I've serviced never even had these blend air systems installed/or installed correctly. Do you even have an attic? Does the vent actually go outside? If you answer no to either of these questions I wouldn't even worry about it.

In our mobile home we have blown insullation above our ceiling and an air space between that and our roof. The vent fan serves two purposes. It replaces hot air above the ceiling with cooler outside air in summer months to help cool thehouse. In winter months it replaces damp air above the ceiling with drier outside air to prevent condensation and ice buildup above the ceiling.