this video has tons of information thanks guys!!!!

thx, enjoyed the jazz music too

That tee flue connector for that water heater no longer meets code. You must install a Y now instead of the Tee. Otherwise, it is correct, in that the smaller BTU appliance is connected to the highest vertical point on the common flue vent.

Well met!

then all the aspects of trouble shooting might have been lost........as far a thinking "out-of-the-box". Like you said, a quality video

This is a quality video. On the other hand i believe that you are using some dated methods when it comes to checking the heat exchanger. With a flash light and mirror you are only able to check about 10% of that heat exchanger. Also I would have have checked the gas pressure way before I thought the orifice size was the problem. That is a old furnace that has been running for many years with those orifices. I will not talk about the flue situation i am just going to leave that one alone.

Wow..back to the 70’s...mercury in that thermostat bulb...the heat exchanger Test is ok..you can see up there pretty good..turn the fan on and see if a match or taper blows around...it should stay steady. The water heater flue must be installed in the larger diameter flue pipe....cantgo into the same pipe size as the furnace.must increase in size..the tee or y has to be lowered. The water heater relief valve drop leg is up too high...I believe it should be 12” from the floor.. Furnace..not boiler.. flame rollout.???...that’s usually a cracked heat exchanger. Not being critical..just my observations.

I'd have no hair if I didn't use a drill