Derek;

After looking at your photo's [quite helpful]

1) The filter in the door is a 'pleated filter' and could be more
restrictive to air flow causing your furnace blower to suck from other
area's.

2) The filter housing in the door doesn't appear to seal well. I'm curious
about the white panel board on the door. Was that there when you bought the
house? It seems it prevents the door from sealing against the framing and
might cause a slight gap at the top of the filter just below the burner
area. This would cause a suction and bring the flames out. [Today code
doesn't allow for the return to be drawn through a door like the one you
have.]

3) I see there's very little clearance on the sides of your furnace, not
allowing for lower combustion as required by code.

4) Since you replaced the blower belt, you may have increased your chance
for the problem to become more evident.

5) The furnace has to be on the high side of 35 years old. Replace it with
a newer high efficiency model, and you will eliminate the possible hazards
to your family. The newer furnace will be smaller, thus allowing for code
corrections.

6) If I bought that house, I would have replaced that furnace yesterday.

--
Zyp
"derek" wrote in message
.191...
Hi Turtle
I got up in the attic and checked the air intake and it was wide open. I
could look down the pipe into the closet. I got up on the roof and
checked the exhaust and everything looked good as well. I can't find any
kind of exhaust fan on the unit.
I posted some pictures he http://home.earthlink.net/~tig414/furnace/
What concerns me about this is why did a unit that operated for 30 years
suddenly develop a roll out problem. There have only been Three things
changed relating to the system. The thermostat, The main gas meter
outside the house, and the drive belt on the blower. The drive belt was
really old and slipping badly. I changed it out and I suppose I could
reason it out that the increase in draw with the extra rpms could make a
difference but that takes me back to why is it starting to happen now.
The closet door holds the filter and there is no sealing between the
filter frame and the furnace frame when it's closed. I removed the filter
from the door and there is a 1'' gap between the top of the filter frame
and the furnace. If I understand you correctly on how this is supposed
to operate then this can't possibly be right.

I'm not going to do anything until I install the roll out protection I
also have some high tenp insulation blanket that I use in my kilns and
I'm going to protect the wires with that. I'm going to use an incremental
approach to solving this Starting with improving the safety system and
sealing up the filter frame to furnace connection.
I'm not an idiot and I'm not out to kill my family. I've built two kilns
that both run on gas and reach temps in excess of 1500 degrees for days
at a time. They have redundant safety systems and are temperature
controlled via microprocessor units that feed real time data to a
central server in my shop. I've built two metal melting crucible
furnaces that reach temps of 2500 degrees for melting bronze.
I know you've taken some flack for helping me on this and I really
appreciate your help.
The quality of service technicians and tradesmen in all industries
including mine has diminished over the years for various reasons and has
made me into the do it myself person that I am. Also I'm really broke
right now! There's a difference between being cheap and being poor.
Thanks
Derek