On Thursday, December 15, 2005 at 7:52:34 AM UTC-6, wrote:
We just had a complete new Carrier system installed. Top of the line
high efficiency gas furnace (96%) and central air condenser (18 SEER).
The thermostat is an Infinity Control model which is supposed to
eliminate the hot/cold syndrome of forced hot air heat.

Well, it sure as hell hasn't done that. This unit doesn't recognize a
change in the room temperature until it's changed by at least three
degrees. That means it gets very cold before the furnace kicks on. It
stays on for a long time - sometimes twenty minutes or more, then goes
off for as long as an hour. It's four degrees outside right now and
the furnace came on once in the past hour. When it does go on and off
it "thinks" that the inside temp has changed by one degree when in fact
the swing is about five degrees.

The guy who installed it agrees there is a big problem but he is having
trouble convincing Carrier.

Does anyone else have a similar problem with this new model? It's very
frustrating considering the little sucker cost about $400.

Thanks

Jane

Those thermostats have what's called an adjustable offset which means the temperature difference at which it turns on the HVAC system. It can actually be programed for a one degree difference even though most I've seen were set to 3 degrees. The offset keeps the system from turning on and off too many times per hour. You may also see it referred to as hysteresis. It can also be adjusted to come on at exactly your setpoint and cut off at a temperature 3 to 4 degrees higher than what you set it for. Electronic thermostats can be programmed to operate in many different situations but it takes someone who understands what is needed. 8-)

[8~{} Uncle HVAC Monster