After much research I learned the H.A.C. altitude compensator units on 95-98 Summits should have the calibration checked annually, at least for the first few years. The calibration is easy to adjust.
You can test general operation by placing unit in the freezer for an hour or so, then measure the needle position. After it warms up to room temp it should move 1-2mm approx.
Here is a close estimate of needle position at 20 degrees F, 30.08 barometric pressure:
1184 ft = 10.5mm from top of tube
7266 ft = 7.4mm
8554 ft = 6.6mm
10,000 ft = 5.6mm
1184 ft at 73 degrees F = 9.1mm
PM me if you need figures for other altitudes or temps.
You can test general operation by placing unit in the freezer for an hour or so, then measure the needle position. After it warms up to room temp it should move 1-2mm approx.
Here is a close estimate of needle position at 20 degrees F, 30.08 barometric pressure:
1184 ft = 10.5mm from top of tube
7266 ft = 7.4mm
8554 ft = 6.6mm
10,000 ft = 5.6mm
1184 ft at 73 degrees F = 9.1mm
PM me if you need figures for other altitudes or temps.
