On Mon, 11 Dec 2006 14:21:18 -0600, "Jimi"
wrote:


"Puddin' Man" wrote in message
news

Hi,

I've got a new Heil 1-stage upflow furnace (installed last Apr.) in
my little brick bungalow in the midwest.

The heat cycle is something like:

T-stat calls for heat
LIttle fan sucks fumes out.
Heat element gets power.
Gas valve opens, burners fire
Blower kicks in
Gas valve closes
Blower kicks out

Occasionally and only intermittently, after the heat cycle
has been complete for some time, the blower will run for
about 10 seconds and then shut down.

The furnace fan is designed to kick in when the heat exchanger reaches a
certain temperature. What is happening in your case is the fan is not
running long enough to cool the heat exchanger after the heat cycle. The
residual heat in th exchanger tells your fan to kick back in to cool it down
for those 10 or so seconds. You have to set the fan to run longer after the
heat cycle and this will prevent the fan from kicking back in. There is an
adjustment in the furnace.

I think you've nailed it.

I somehow expected a senser to shut fan down when the HE cooled
to a certain temp.

There's a jumper for timed shut-off of fan: 30, 60, 100, etc
secs. 'Twas set to 60.

I set it up to 100. If it blows too much cool air, I guess
I'll go back to 60. It wasn't re-cycling very often (maybe
1 heat cycle in 10) and I doubt it'd hurt anything.

Mostly I just needed to know what was going on. Might hafta
maintain/repair this unit for many, many years.

Much Thanks,
Puddin'

Pease pudding hot,
Pease pudding cold,
Pease pudding in the pot
Nine days old ...