My Rheem gas furnace keeps blowing cold air. Yesterday this started and when upon furthur inspection the pilot light was out so my husband lit it. Not about 10 minutes later did the same thing happen. The pilot was out and the vents were putting out cold air. We did this several times and still nothing is working. I have a repair man coming this afternoon but I am hoping to find this one out on my own and save a few bucks since he is charging us $70 for the first hour! Thank you!