Steve Wiggins said:hmmm do you know if your unit has a two stage gas valve? It might be only on low stage, just a guess. Can you take a temp meausrement of the differential between the supply and return air?
BTW thanks for filling out your profile. Being an engineer with Lucent I am going to assume you have more than one system on the home? If so you might be able to compare temps. Question, do you also have cooling with your new system(s)?
Steve Wiggins said:with those temps it is definately on full fire. I don't know about your area or your R-values for sure but I suspect with the square footage that your furnace might be a little on the small side. It is only 75,000 btu input and 20% of that goes up the flue so you are only getting 60,000 btu in the house. To verify this theory you could run a heat load calculation or ask the builder if one was done when the house was built three yrs. ago.
Steve Wiggins said:Keep plenty of good airflow by not closing off vents. Keep mother earth out by filter changing but never use an electrostatic air filter. That spark ignition comfortmaker's pilot orfice will get dirty and cause the pilot flame to be weak. I would say about every 3-5 years take out the orfice and blow it out with compressed air. Also blow out the air intake to the pilot at the base of the orfice holder. Keep a close eye on the vent pipe and make sure it doesn't drip any white milky substance down on the controls. I see in your pic a brown stain on the heat sheild right above the left burner. I can't tell but it might be from water dripping above? I think I see a cooling coil in your pic (take another pic further back) so don't let it overflow on your delicate furnace controls, circuit board etc. no one ever adds a secondary overflow drain to those upflow units even though there is a plug for one and the code requires it. Inspectors never enforce it.....what a shame for the consumer. That coil can produce up to 10 gallons of water on a hot summer day and will ruin a hardwood floor before you realize there is a problem. If the unit is upstairs it can rain down havoc on the building contents below.
If I were a rich guy like you I would jerk that comfortmaker out and install a 96% Amana gas furnace with a lifetime warranty stainless steel tubular heat exchanger. This way only 4% of your heat would go out the flue instead of 20%.