The furnace seems to start up small fan starts OK the flame lights then the gas shuts off and the flash code flashes 4 times (limit switch open)??

This is a wild shot but if the furnace shuts down right away after it fires up try cleaning the flame sensor with fine sand paper or steel wool.

I will try that - since I asked the question I cycled power approx.6 times and it started and my house is getting up to temp I will clean the flame sensor when it stops Thank you very much