Does anyone know where in the UK I might get hold of a proper - preferably adjustable, or fixed at 125psi - pilot valve? at least, I _think_ that's what it's called; basically, once the air pressure in the receiver reaches the set pressure, this valve pops open; and sends a small amount of pressure to the valves on the top of the compressor which stop it compressing. I thought it was called an unloader valve, but that does something else...
Basically, my compressor is engine driven, so rather than trying to stop/start the engine when the pressure varies, the pilot valve simply shoves a pair of small valves open on the compressor head which prevents it from adding more air to the tank. When the pilot valve drops shut, the compressor kicks in again.
I recently bought a 3phase compressor which had such a device on it, but that's over with the racing cars (and is in use on the compressor); I've been relying on a safety valve, but it's not ideal.
