Re: [VAL] Heater

["Mark" <mark@xxxxxxxxxxxxx>]

Hi Tom,

Well, you're on the right track!  Did you remove the burner assembly?  It
wouldn't draw a crowd of cameras if the slots in the burner were rusted.  If
memory serves, the slots are exactly one hacksaw blade wide (convenient, eh?),
and you can slice the rust and crud out with a couple of gentle strokes (you
don't even need a hacksaw frame, just the blade).

What MIGHT be happening is that, if the slots are rusty, and partly closed up,
the gas may not be getting up into the flame, and a bit of raw gas is building
up in the burner or heat exchanger..then it lights off all at once.

Since you had the guts out once, it shouldn't be too terrible to do it again.
At the same time, you can look into the exhaust port to see if there's
anything in there (wasp nests, etc.).

Did you tell us which model furnace you have?  Mine is the NT series, but they
should all probably be pretty much the same.  When you first turn it on, the
blower should come on by itself, to purge the system of any fumes.  You should
hear a little click (the sail switch) when it first starts to blow.  This
tells the rest of the controls that air is moving through the chamber, and
it's OK to let the gas flow to the main burner.

POOF...the main burner lights.

When the temperature in the room is reached, the main burner shuts down, but
the blower keeps blowing, scavenging any heat left in the heat exchanger until
a heat sensor tells the fan to shut off.

Hope that helps some more,

Mark in Modesto