Ram air valve
 

Can someone tell me what a ram air valve in an airconditioning unit does thanks?

Generally the purpose of the ram air system is to control the outside air flow (ram air), through the heat exchangers during flight and in ground ops to satisfy the temp requirments of the cooling pack
Hope this helps a little

Actually it is used to RAM outside air into the cabin (use below 1 PSI please) and is used in the smoke drill to clear smoke from an unpressurized cabin.

In the event of pack failures etc it can provide outside air to ventilate the cabin.

Pressing the valve with the packs in Automatic will also cause the outflow valves to open rapidly and depressurize the aircraft. Hence the caution about 1 PSI.

Cheers
Wino

Thanks Wino for your help, just studying for my atpl. thanks a million!!!!!!!