Recommended Installation Guidelines - E-Type Systems
The air compressor is an engine driven, piston type compressor which supplies compressed air to operate air activated
devices. The compressor operates continuously but has a loaded and unloaded operating mode. The operating mode
is controlled by a pressure activated governor and the compressor unloading assembly. Intake air can come from the
intake manifold or near the engine air cleaner.
For an E-Type unloader system used with an air dryer, an Econ valve, and check valve with makeup line must be
installed in the air system, or an approved dryer incorporating all valves must be used. The Econ valve must be
mounted in a position and altitude to avoid collecting condensation which can freeze during cold weather. The Econ
valve must be installed with its inlet port above the outlet port to avoid condensation traps in the discharge line or
fittings, per normal recommended installation practice for air compressor discharge lines.
The air inlet temperature for the Econ valve must not exceed the inlet air maximum temperature recommendation of
the air dryer manufacturer. When possible, the Econ valve must be 2 to 7 feet from the air compressor or the air dryer
must be 8 to 10 feet from the air compressor. The air discharge line must be downward sloping from the air
compressor outlet air port to the air dryer inlet air port.
The differential check valve must be installed either on the upper part of the wet tank, or on the side of the dryer outlet
fitting to avoid condensed moisture (see option diagrams below).
It is critical to have the poppet end of the differential check valve installed toward the wet
tank or toward the air dryer outlet.
Use of a differential check valve other than the identified part, can result in system
malfunction. Contact the dryer manufacturer for recommendation.
To prevent overnight or shutdown freeze-ups of the Econ valve not confirming to the 2 to
7 foot Econ valve location, make sure that the vehicle wet tank is drained to below
governor cut-in pressure (via wet tank drain valve) following vehicle shutdown. This
action will open the Econ valve and allow compressor air flow at vehicle start-up.
Air Compressors Installation Diagram with Turbocharger Air Dryer and E-Type