Can't find my manual and my furnace seems to be having a problem starting. Can hear and see the furnace click on, starts to warm and just when, I think it's some type of blower I hear normally kicks on, it seems to shut down and try to restart again. Usually it will eventually fire up. Sometimes I will shut down the power to the furnace and then turn it back on and it will fire up ok. Can you send me a manual and any ideas on the problem. I've only had the furnace for about 5 years.