What is the recommended furnace blower off delay time? The times available are, 60, 100, 140 & 180 seconds. The unit came set at 140 but it blows cold air after about 120 seconds. I changed it to 100 and now it still blows a little warm before it shuts off. I'd like to set it to 60 seconds but I don't know if that's too short of an off delay.

A 1 minute (60 secs) run should extract most of the heat from the exchanger. Try it there and go back to 100 if you think the air stream is too hot. You don't want to waste heat. Have you ever checked the air temperature at 90 secs? Should be near body temp or it will always feel cool due to skin evaporation. Small dial thermometers are $5 at Harbor Freight and other stores. Put it in the vent nearest to your normal sitting position in a room and time to 90 seconds after the flame goes out. What does it read?

Great information! I have digital thermometer with a probe, I 'll place the probe in the vent and check the temperature at 90 seconds per your recommendation. My concern is two fold, I don't want cold air blowing out the vents but I want to make sure the heat exchanger is cooled down enough so as not to cause any damage to the furnace. What's your recommendation on furnace filters? I try to use the lowest restriction filter I can find. I avoid the blue/green fiberglass and get the low restriction pleated filters. The furnace originally came with a very nice white spun filer media filter that seemed to filter quite well with little or no restriction but I haven't been able to locate any filters like that locally.

Glad to be of assistance. Newer filters are rated in MERV's (efficiency ratios) using a variety of dusts. Most people find a MERV 6 or so to be a good general use filter ratio. Less than that they don't filter well and above that they can get dirty fast if you have pets, keep windows open etc. PS-you can "tip' me by clicking YES is this helpful. Thanks, Brian (ma0641)