Below is info on this unit.http://b2b.frigidaire.com/support/ResultsPage.asp?strModel=FER211AS2&User=&Search=Search
There are a couple ways you could jiggery pokery this.
1: Place the timer on timed dry/cool down and check to be sure that the unit does not have heat.
Disconnect the timer motor C wire from the timer and wire in a switch between the timer wire and C on the timer.
With the switch closed the unit should work as normal.
With the switch open and the timer set on timed dry/cool down it should give air only but the timer will not advance.
2: Disconnect the wire from timer lug A and wire in a switch.
This is disconnecting L1 from the heater.
Th heater takes about 21 amps so the switch needs to be 240 volt 30 amp minimum.
Also any connectors need to be high current and any wire used must also be able to handle 30 amps minimum.
This in more complicated and the chance of creating a poor connection which could heat up is higher so be extra careful with all connections.
The nice thing is that now the timer will advance/work in timed dry but it will not have any heat.
You will have to figure out how and where to mount your switch so that it is safe.
Also it will void any warranty on the unit.
Just as a reminder be sure that the unit is unplugged when doing any of the above.
Also you are doing this at your own risk