Thermo King SLXi Spectrum, Maintenance Manual

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Operating Instructions 6-17
DEFROST TIMER.
A solid-state defrost timer automatically places the unit on Defrost every 2, 4, 8 or 12 hours, depending on
the interval selected. On TG-VI, MT µP-IV, µP-V, µP-VI , SR-2 and SR-3 controllers, the defrost timer function is built into the
controller menu display.
HEAD PRESSURE CONTROL SWITCH (HPCS).
On SPECTRUM models with a Multi-Temp MT µP-IV controller, this
switch confirms the operation of the receiver tank pressure solenoid and purge valve to control the refrigerant discharge pressure
when a zone is in the Heat or Defrost mode.
DISCHARGE PRESSURE SENSOR.
This sensor monitors refrigerant pressure in the discharge line to control the discharge
pressure when a zone is in the Heat or Defrost mode. (Not available on some units)