Air Circulation And Cooling; Compass Safe Distance - Garmin GTN 625 Installation Manual

3.8 Air Circulation and Cooling

CAUTION
To avoid damage to the GTN, take precautions to prevent Electro-Static Discharge (ESD)
when handling the GTN, connectors, fan, and associated wiring. ESD damage can be
prevented by touching an object that is of the same electrical potential as the GTN before
handling the GTN itself.
The GTN unit meets all TSO requirements without external cooling. However, as with all electronic
equipment, lower operating temperatures extend equipment life. Reducing the operating temperature by
27° to 36°F (15° to 20°C) greatly reduces the mean time between failures (MTBF).
Units tightly packed in the avionics stack heat each other through radiation, convection, and sometimes by
direct conduction. Even a single unit operates at a much higher temperature in still air than in moving air.
Fans or some other means of moving the air around electronic equipment are usually a worthwhile
investment.
The GTN has a cooling fan integrated into the backplate to draw forced-air cooling through the unit. There
are inlets along the left, right, and bottom sides of the GTN bezel that allow air to flow through the unit.
Ensure that there are no obstructions to the air inlets or fan exhaust. Air should be able to freely flow from
the bezel inlets to the backplate fan outlet on the rear of the unit.

3.9 Compass Safe Distance

After reconfiguring the avionics in the cockpit panel, if the GTN unit is mounted less than 12 inches from
the compass, recalibrate the compass and make the necessary changes for noting correction data.
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Rev. F
GTN 625/635/650 TSO Installation Manual
Page 3-11