What the unloader valve does is that is responds to the compressor pressure switch turning the power off to the motor and allows any air that may be trapped over the piston or pistons on a multi cylinder air compressor to vent to atmosphere removing any load that the trapped air may have.
Volvo d13 air compressor unloader valve.
If your electrically powered air compressor is having a hard time starting try pulling the power cord and opening the drain valve to void all air from the tank.
Volvo 2014 d13 it says air dryer malfunction on dashboard i have replaced air dryer assembly.
The compressor s unloader mechanism and governor along with a synchro valve for the bendix duraflo 596 air compressor control the brake system air pressure between a preset maximum and minimum pressure level by monitoring the pressure in the service or supply reservoir.
As the system reservoir air pressure drops the force exerted by the air pressure on the piston will be reduced and the governor spring will push the piston down.
Plug the compressor back in.
In some cases the air compressor may have a cracked head or develop a hole in the cylinder wall.
Page service bulletin 2 2007 215 46 5 25 8 w2006005 loosen the clamps and remove the main fresh air pipe clamp from the air compressor fresh air hose the air filter.
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My air compressor is leaking coolant internally externally.
Reservoir air flows around the inlet valve through the passage in the piston and out through the unloader port 2 to the compressor unloading mechanism.
2009 international prostar purges air every 15 seconds already replaced governor purge valve air compressor head for the unloader valve and a new signal line from governor to the air compressor.
This will effectively emulate the operation of the unloader valve as any air trapped over the piston will flow into the tank as the tank pressure drops.
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