Last winter we went up to Grandma Susie’s for a visit. Upon walking in we noted that the temperature in the house was about 64 degrees. We casually mentioned this and Susie was at her wit’s end. She had the furnace guy out two times already and every time he arrived he'd go down stairs, come back up and report that the furnace was working fine. But as soon as he left, the furnace would stop working. I immediately went down stairs and the furnace was working. I went back up and reported this to Susie and she shook her head in disbelief. She claimed that she was cursed because when she went down the furnace would stop working. About ten minutes later I decided to go back down and see if it was still on. It was not. I toggled switches and checked the lines and reset the reset button. Nothing. Once again the furnace dude was called.
Being a guy, I went back downstairs several times before the furnace dude arrived to see if the system had kicked back on. It had not. When the furnace guy arrived, he said hello, went down stairs and came right back up. “The furnace is on.” I went down and checked… it was on.
The furnace dude left us with a business card with a psychiatrist’s phone number scribbled on the back.
Fifteen minutes later I was down in the basement looking at a furnace that wasn’t working.
We left a few hours later with the furnace still not working.
We heard back from Susie the next day. The furnace company was so sick of her calling that they sent out Furnace Dude Numero Uno to take a look at her situation. He showed up, went down stairs and the furnace was working. He then pulled up a chair and sat down in front of the furnace and waited for the tea kettle to start boiling.
And five minutes later it did. The furnace sputtered out. He could not get it to re-start.
Because this furnace dude was The Furnace Dude, he went back to Fire 101 which states that you need three things for fire: fuel, oxygen and ignition. Fuel and ignition were present and accounted for. He went to check on oxygen.
Jump back in time six months previous and Susie was having an issue with wasps on her patio. They had a nest in a pipe that was coming out of the house. She took out the nest with some Raid and removed the soggy remnants with a broom handle. To keep the wasps from returning, she put a stocking over the hole. And then she forgot about it.
Furnace Dude removed the stocking from the air intake and the furnace happily took a deep breath of air and ignited. After that it stayed on. Done and done.
But wait… what about the sporadic lighting? Why was the furnace always on when the original furnace guy or I were in the basement? As a clever boy, I realized that every time the front door was opened, it would allow for what ever vacuum had formed in the furnace’s guts to be released. As it was trying to suck air in from the blocked exterior pipe, it was also pulling in whatever surrounding air inside the house that it could. When the front door was opened, the resulting change in pressure allowed just enough air in for the furnace to ignite just long enough for the furnace dude to think Susie was just enough batshit crazy.
The moral of this story is nestled somewhere in between “experience requires patience” and “Susie is always right except in reguards to pest control,” but I don’t know where.