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GregS[_3_]

In article , (GregS) wrote:
In article , krw
wrote:
In article ,
says...
On 2/27/2009 10:58 AM spake thus:

This is Hunter Fans Digital Thermostat Model 44360.

Lately its calibration is off by 2 to 4 degrees.

You've probably already looked for this, but are there any adjustments
(like trimmer pots) on the board?

There is often a "heat anticipator" setting that when whacked will
throw the calibration off. It's purpose is to compensate for the
thermal mass of the building and look at the rate of the
temperature rise so it doesn't overshoot. Some are better than
others.

On good thermostats the computer program adjusts the anticipation
or really looks at PID. Some also have fuzzy logic.

A thermister uses resistance to set temp calibration and gain to
adjust linearity. If any of these variables gets thrown off, they
need to be adjusted. They would be a pot of some kind.The
thermister is probably OK.

What I meant about the good thermostats, they look at the temperature
swing and adjust the programming to compensate. Its an on going
process. There is no way of knowing by reading the specs i just did,
to know how it opperates, unless it says.

Air currents around the thermostat can be tricky. The best method
I have found is to measure the thermostat with an IR gun. But
you said you dropped it, and I would suspect miscalibration.

greg