Operation Manual P750/P1500/P3000
Cold Jet, LLC Page 26
o Check the hydraulic cylinder proximity switch lights. All must be on to determine
the piston position and switch power status. The rear switch light must be red
(indicates the piston is at the home position).
o Locate the hydraulic directional control valve solenoids. In the center of the
solenoid is a manual override brass button. With the system switched OFF, and
the hydraulic motor running, depress the manual override to retract the piston
until the proximity switch light on the hydraulic cylinder illuminates red. Turn the
system ON again. If the Pelletizer still does not run, repeat the procedure on the
other solenoid. (All the proximity switches must have the indicator light
illuminated or it will not operate).
• Disconnect the yellow cable from the hydraulic directional control valve solenoid and
measure the solenoid resistance. It should be 33-35 ohms. If either solenoid is
defective, neither cylinder will operate.
• If neither proximity switch is illuminated then its cable may have failed. Disconnect the
proximity switch cable and check for 115 VAC. If power is present the proximity switch
has failed and must be replaced.
Pellet Quality
• Pellet quality is determined by extrusion speed and moisture content of the CO
2
supply.
• Dirty collector screens degrade pellet quality because the gas cannot rapidly escape.
This results in reduced production and brittle pellets.
• If connected to a gas recovery system and the backpressure exceeds 20 psig (1.4 bar),
then pellet quality diminishes.
• When brittle pellets are transported, they can break into “fines” or snow then form a
solid CO
2
“snow cake” within a few hours.
To avoid these problems check the following:
• The extrusion cycle should be between 12 and 13 sec.
• The pump shift point, from high volume to low volume, should be between 1000 to
1500 psig (68.9 to 103.4 bar).
• Check the condition of the collector screens.
Low Pellet Output
(Less than 1200 lb/hour (545.5 kg/hour))
Low pellet production can be caused by several factors:
• Poor insulation of the liquid supply line.
• The size of the supply line compared to the distance and number of Pelletizers being
supplied.
• The capacity of the gas recovery system versus the back pressure.
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