Wiring A/C to a old Lennox furnace

[walker]

I was having trouble today trying to wire up an air conditioner to an old Lennox that uses a fan-limit switch to control the blower, I can get the heating side to work correctly using the fan-limit control and a transformer but I couldn't figure out how to get the A/C side wired up correctly. Anyone have a diagram of how i  would add in the air conditioner, I also couldn't get the fan only mode working correctly, I'm not sure where the G terminal and Y terminals should go, I think I should be adding a relay in somewhere but I just couldn't figure it out today. Does anyone have an idea or diagram of how to set this up?

Thanks

[harshal]

HI,
U would need the fan centre for a/c hook up,but make sure u dont bypass the limit switch.The best way to chk the limit bypass is to put the fan on/heat mode then to see the gas cuts off when the dial reach the at the cut off setting (200 f)on the fan limit control.u would find the diagram on the fan centre.

[Admin]

http://www.hvactechgroup.com/hvacforum/index.php?topic=1289.0

[walker]

Guess I'll need a fan center, I've seen it done without one, I just couldn't figure it out.

Thanks for the help guys