CDI Control Devices P25 Pilot Unloader Valve - 110-130 and 160-175 PSI
CDI Control Devices P25 series pilot unloader valves. On a constant run or engine driven compressor the pilot valve is what the pressure switch is on an electric start machine: it senses tank pressure and sends the control air signal that unloads the pump at cut out and loads it again at cut in. The motor or engine never stops, so the pilot valve is doing the controlling.
Pressure ranges
- S1010, CDI P25SJ: 110 to 130 PSI
- S1604, CDI P25S-T: 160 to 175 PSI
Picking the range
Match the pilot valve range to the working pressure of the machine, not to the tank rating. A 175 PSI two stage package wants the 160 to 175 PSI valve. A single stage unit running a shop at 125 PSI wants the 110 to 130. Fitting a 160 to 175 valve to a single stage pump will run the pump well past where it should be working, and fitting a 110 to 130 valve to a two stage package means it unloads long before the machine has done its job.
What a failing pilot valve looks like
The pump will not unload at cut out, so the engine screams against a loaded pump or the motor labours and the safety valve lifts. Or the opposite, it unloads and will not load again, so the machine runs on and never makes pressure. Hunting rapidly between loaded and unloaded is also a pilot valve symptom, and so is a slow lazy response that makes a perfectly good bullwhip or engine idler look worn out. Check the pilot before you condemn the idler.
Installation
Pipe the sense port to tank pressure and keep the control line to the unloader or idler as short and as clear as you reasonably can. Use thread sealant rather than tape on the control fittings, because tape shreds and a fragment in a pilot valve seat will make it leak down. After fitting, run the machine through at least two full cycles and confirm both the cut out and the cut in points before you leave it.
Related parts
We also stock Conrader discharge unloaders with toggle and with shutoff, bullwhip idler throttle controls, engine idler assemblies for Honda and Kohler engines, the complete KD diesel idler kit, and Lefoo pressure switches with unloader for electric machines.
Not sure which one
Tell us the compressor make and model and the pressure the machine is set to run at, and the Warthog Air Compressor Store team will confirm the right valve before you order.
CDI Control Devices P25 pilot unloader valves for constant run and engine driven air compressors, in 110 to 130 PSI and 160 to 175 PSI ranges.
NOTE: Actual product may be different from pictured!
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