I had a weak compressor on my car and bought a new one. I fitted it and now have a problem where it won't drop the ride hide and gives several codes for the high pressure valve. Before fitting the compressor, this was never a problem. The operation of the compressor seems fine and builds air must faster than it ever did .

I removed the valve assembly from the two air lines so they weren't connected to anything ,and when selecting the drop the ride height it will dump the air and settle in the normal driving position and stop the air release. Thinking this was somehow the valve playing up, I ordered a new one and fitted it, but the same problem persists.
Does anyone have any ideas, or is there a small chance the new valve is duff ?
Thanks

Valve p/n MAV500010

Could this thread explain your problem and offer a solution.

https://www.fullfatrr.com/forum/topic23038.html

Thanks, but hopefully shouldn't be as this is a new compressor, plus the one in that thread is a different compressor.
The valve I removed is the brass one in the spare wheel well. Removing the two air lines allows it to drop from off road to road normally. It vents and stops at the correct height and the dash switch stops blinking. As soon as I put the air lines back on the valve assembly, the switch blinks to drop but nothing vents and no drop.

Have I got it right that when selecting a lower ride height, the air is dumped from this brass valve, or is it on the compressor?

iirc that is the PRV - pressure relief valve .
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What should have been a simple job has turned in to a real pain in the arse. Had the new pump out several times and checked everything, nothing different happened except getting more trouble codes.

Put the old pump back on and the old weak pump raises the car and now lowers the car as before, except now i don't get the dash warning for off road mode, so probably out of calibration ?

Not sure what else to do but assume the new pump ( Aerosus brand ) is causing a fault and return it and hope I get a refund.

hi from what little i know ,the actual exhaust solenoid is mounted on the compressor head. this way the exhausted air is fed through the dessicant air filter .
Ive read on here that sometimes when they wont lower on the compressor wabco type theres a conical shaped brass filter that the exhaust air has to go through . These block so sometimes people drill a 3 mm hole in them .
If your original pump is "weak" you can buy a seall kit off the net for about £15-20 and its fairly easy to do with loads of videos on you tube

Thanks for the reply. Bought a new compressor head and seal from AliExpress and it works perfectly, all on the old frame/air release valve. Still have no idea a new compressor alone caused so many problems on the old original frame .

im no expert but that bi brass thing is an emergency relief valve . as someone said the ecu opens the valves and with the compressor off the air goes back through the dessicant and is vented to air . the cone shaped thing blocks often so yep drill a hole in it .
I thinkthe actual drop is achieved by the ecu switching off the compressor and opening the air suspension valves that are under the drivers door in the sill .