Grizzly T21888 - Manual (Page 22)

model t21888 (mfg. since 2/10) - 20
-
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.
pressure switch 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.
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.
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.
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.
NOTICE
figure 22. pressure adjustment screws.
Cut-in and
Cut-out
Adjustment
Cut-out
Adjustment
only
figure 21. pressure switch cover.