Electrical: General tips (part 2 of 2)

Short, practical technician tips on electrical for general. Check each one against the manual for your exact model before acting.

Thermistor types

Generic

NTC: resistance falls as temp rises. PTC: resistance rises with temp. PTC in series with a motor cuts current when it overheats.

Thermostat height and stratification

Generic

Stat mounted high reads warmer/more humid than occupants feel; too low reads cooler. Room with no air movement stratifies (e.g. 70°F floor → 78°F ceiling).

Unloaders vs cap-tube systems

Generic

Systems with capillary tubes equalize pressure on the off cycle and don't need an unloader; TXV/AXV systems without bleed ports start against load and need a high-torque motor or hard-start.

Wattmeter vs VA rating

Generic

Manufacturers list VA; a wattmeter reads true watts and self-corrects for power factor; a motor drawing more than rated watts is costing money.