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Reversing Valve Description/Operation
The Reversing Valve controls the direction of
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consists of a pressure-operated, main valve and
a pilot valve actuated by a solenoid plunger. The
solenoid is energized during the heating cycle
only. The reversing valves used in the PTAC
system in a 2-position, 4-way valve.
The single tube on one side of the main valve
body is the high-pressure inlet to the valve from
the compressor. The center tube on the opposite
side is connected to the low pressure (suction)
side of the system. The other two are connected
to the indoor and outdoor coils. Small capillary
tubes connect each end of the main valve
cylinder to the "A" and "B" ports of the pilot valve.
A third capillary is a common return line from the
ports to the suction tube on the main valve body.
Four-way reversing valves also have a capillary
tube from the compressor discharge tube to the
pilot valve.
The piston assembly in the main valve can only
be shifted by the pressure differential between
the high and low sides of the system. The pilot
section of the valve opens and closes ports for
the small capillary tubes to the main valve to
cause it to shift.
Testing The Coil
The solenoid coil is an electromagnetic type coil
mounted on the reversing valve and is energized
during the operation of the compressor in the
heating cycle.
1. Turn off high voltage electrical power to GE
Vertical Zoneline.
2. Unplug line voltage lead from reversing valve
coil.
3. Check for electrical continuity through the coil.
If there is no continuity, replace the coil.
4. Check from each lead of coil to the copper
liquid line as it leaves the GE Vertical
Zoneline or the ground lug. There should be
no continuity between either of the coil leads
and ground; if there is, coil is grounded and
must be replaced.
5. If coil tests OK, reconnect the electrical leads.
6. Make sure coil has been assembled correctly.
NOTE
: System operating pressures must be near
normal before the valve can shift.
NOTE
: Do not start the GE Vertical Zoneline
with solenoid coil removed from valve, or do not
remove the coil after the GE Vertical Zoneline is
in operation. This will cause the coil to burn out.
Summary of Contents for GE Vertical Zoneline AZ90E09D C
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