Grizzly T21888 instruction manual Pressure Switch, To adjust the pressure switch

Pressure Switch

The pressure switch ensures the compres- sor will turn ON (cut-in) when the tank pressure drops to approximately to 85 PSI. The compressor will shut OFF (cut-out) when the air tank reaches maximum of 115 PSI. Should the cut-out switch fail, the pressure relief valve will open at 130 PSI, preventing tank explosion.

NOTICE

The cut-in and cut-out settings have been factory set at the proper PSI range. Only adjust the pressure switch if your air compressor is cut- ting-in or cutting-out at the incorrect pressures.

To adjust the pressure switch:

1.Operate compressor and record com- pressor cut-in and cut-out pressures.

2.DISCONNECT THE COMPRESSOR FROM POWER, AND DRAIN ALL AIR FROM THE TANK.

3.Make sure the compressor switch is in the OFF position.

4.Using a #2 Phillips screwdriver, remove the switch cover shown in Figure 21 and hinge back the cover and set it aside.

Figure 21. Pressure switch cover.

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If only the maximum tank pressure needs to be adjusted, then turn the cut-out adjustment screw (Figure 22) a half turn clockwise to increase the tank pressure, or a half turn counter- clockwise to decrease the tank pres- sure. The cut-in setting will remain unchanged. However, keep in mind that the allowable pressure differential between the cut-in pressure and cut-out pressure must be kept between 30-40 PSI. Exceeding this range can cause the compressor to overheat.

Cut-Out	Cut-In and
Adjustment	Cut-Out
Only	Adjustment

Figure 22. Pressure adjustment screws.

If the minimum and maximum tank pressure settings both have to be raised or lowered at the same time, then the cut-in and cut-out adjustment screw must be adjusted. Turn the cut-out adjustment screw (Figure 22) a half turn clockwise to increase both pres- sure settings or a half turn counterclock- wise to decrease both settings.

5.Reinstall the cover, connect the com- pressor to the power supply, and start the compressor. Cycle the compressor through the cut-in and cut out pres- sures. If the compressor does not auto- matically turn OFF at 115 PSI, flip the ON/OFF switch to OFF before the pressure reaches 120 PSI. If the tank pressure is too high, or any settings are out of specification, readjust the pres- sure switch until all are correct.

Model T21888 (Mfg. since 2/10)