No heat in bedroom

There's a circuit board, and taking the panel off the outside, I can see it. Those can go bad, but this unit is only 4 years old. Why on earth would all this stuff be going bad after only 4 years? That's why I'm unsure if it's because of the cold, partially or wholly.
The service tech should be able to figure it out fairly quick. He's pretty good.
And I replaced the regulator. The indicator has switched from red to green, whereas the old one was stuck on red.

burner could be sooted up, I use compressed air to blow out the fridge, water heater & furnace once a year.

Now appears that the issue may be a stuck float on the second stank, or the little steel ball is stuck inside. You would think they could make these things not so intricate and fragile. But then if valves and regulators lasted for ever, they'd probably be priced beyond value.

I wish bedroom in my Montana was a lot cooler with the heat on. The furnace is under the shower and it is right at the top of the stairs. Heat also rises and with the shape of our roof the heat travels up to the bedroom from the living room unless me close the door.

I think the location of the heater and the shape of the ceiling is by design, so that you can actually have the heat setting lower, and still get the benefit in the bedroom.