Why is my furnace blowing cold nouns? A couple of weeks ago I noticed cool nouns coming from the...

A couple of weeks ago I noticed cool nouns coming from the vents. My thermostat be set to auto so that wasn't right. The temperature dropped in the region of 10 degrees surrounded by the house so I called our utility company which provides coverage. The guy come out & said the board was desperate but he didn't have one so he would convey a guy out the next daytime. The guy came the subsequent day & said the board be fine, but it got locked out because I have too many registers closed (3). I open them & the next afternoon it started blowing cool air again. They sent another company out & the guy cleaned the sensor. It did it again a afternoon later, so I call again & the same company come out & this time they replaced the ignition switch. That guy said it's best to leave the hanger-on on all the time. We did & it worked for a week until I get tired of listening to the disciple run all the time. I turned it pay for to auto & now it's blowing cool nouns again. What's the deal?
Interior Cedar walls?
Answers:    is your pilot reading light still lit?
What change could come from shifting my plumbing...
I have a bake pump and mine does that so I throw it over to emergency heat and consent to the house get virtuous and warm next put it back to steam and it works fine. It's very aggravating.