When I blow into the hose, it's like a soft crinkling sound - similar to the sound a vinyl beach ball makes when you blow it up after it's been flat. Is that the right sound? Also, I have turned the thermostat up to 80 degrees. I'll let you know what happens with that, but I wanted you to know the sound first.
You've lost me here. I don't know what an inducer fan is. Is that when the blower first starts to run before the second stage? I know this - you can't remove the filter while the furnace is on - even if you tried, because the air flow is so powerful.
There is also a small black fan in the back panel area near to the pressure switch and above the burners - it's unobstructed.
Does this help?
So, the black fan assembly above the burners is the inducer fan.
It's completely clear - and it's spins freely. I shut everything down again to make sure it's not damp - I see no sign of moisture - or even any dirt/dust.
The 'pressure switch error' is still flashing after second stage starts up.
So, is that something that a person can do themselves? Or, do I need to call a dealer?