wrote in message
ups.com...
Lately I had been noticing that the temperature of the "heated" air
coming out of my gas furnace was barely above room temperature, 75
degrees by my infrared thermometer. Filter is nearly new, flame is a
perfect blue.

Turns out that the problem was I'd opened up the registers to a couple
of rooms, and the "redumbdant" register in the living room. After I
closed the registers again, the temperature of the heated air shot up
to 110+ degrees at the furnace.

Is it able to maintain a decent temperature in the house with outside at
zero or 10 below that would be common in your area? is the infrared
giving the air temperaure or hte d uct temperature? The purpose of an
ifrared thermometer is to get a reading of "things" that it targets so your
reading may not be accurate. Try a probe or bulb and see what you get.

There is also a specificatio for the heater saying what hte temperature rise
will be. You measure both entering and leaving air and see the difference.
That will tell you if the heater is functioning at capacity.