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EAS pressure switch. Normal function?

6.5K views 3 replies 3 participants last post by  dougburgy  
#1 ·
One would think the pressure switch would be very simple;
-If pressure falls below "X", compressor turns on.
-If pressure builds to "Y", compressor shuts off.

However, with the ECU and all of the things going on, I am sure it is not as simple as my shop compressor (which is as simple as above example).

Example of What mine does:
My gauge never gets to 150psi. Always stops around 140psi. Doesn't seem to have a specific "kick on" pressure. Might kick on at 100 psi, or maybe 120, 130, etc. Sometimes, it will kick on for 30 seconds or so and stop (even though not up to the 140psi) for a couple adjustments (click, click of the solenoids) and then kick on again for another minute or so. Just seems kind of "random" to me.

Does this sound OK or should it be more black and white (ie: kicks on at 110 psi and off at 140 psi, period)?

Thanks!
 
#2 ·
It can stop as a result of heat in addition to pressure, but ultimately the EAS computer controls its operation.

PRESSURE SWITCH
The pressure switch is located in the valve block on both New Range Rover and Classic with the exception of Classic with a VIN up to SA654292. The pressure switch on these models is located on the air reservoir. The pressure switch contacts should be open at pressures below 7.6 BAR (110 psi). The pressure switch contacts should be closed at a pressure of 10.1 BAR (154. Psi) A deviation of ±0.4 BAR (5.6 psi) is allowable for all pressure measurements.
 
#3 ·
pretty much normal,

depending on where you have the gage plumbed in, and how quickly it's using air you'll see different kick-on pressures, but it will be at the same point on the switch. I've seen a pretty big range from switch to switch. some keep the tank at 125psi, others at 150psi and everywhere inbetween. I think it's just manufacturing tolerances.

When the system adds a little air to one spring the pressure at the switch will drop below setpoint, then when the valves close the pressure will come back up, (mainly because of the long/small line between the block and the tank) so the compressor will cycle on/off quickly.