Unit Description
50
Inverted Heat Mode
When the unit switches from cooling in all
running zones to reverse heat, there is a
one-minute period where the purge valve is
energized, while all running zones remain in cool.
This is followed by a two-minute period where
the hot gas solenoid in the zone calling for heat is
energized along with the condenser inlet solenoid.
Finally, the suction line solenoid in the zone
calling for heat is energized. This process
pre-conditions the evaporator in the zone calling
for heat.
The heating system increases the capacity of the
Heat mode by making more refrigerant available
for use in the Heat mode. This is accomplished by
the Purge Valve, which opens during the
beginning of the Heat mode to move liquid
refrigerant from the condenser to the accumulator
where it can be used in the Heat mode. The Purge
Valve controls the flow of refrigerant through the
Purge Valve line. The Purge Valve line runs from
the liquid line upstream of the Condenser Check
Valve to the accumulator inlet. The Condenser
Check Valve is located in the liquid line after the
condenser outlet.
Defrost Mode
The delayed switching of the Hot Gas Solenoid,
Condenser Inlet Solenoid, and Suction Line
Solenoid does not occur before the Defrost mode.
The Purge Valve, Hot Gas Solenoid and
Condenser Inlet Solenoid are all energized at he
same time. The Purge Valve remains open while
the unit is in the Defrost Mode.
Start Up and Sweeping Unit
Evaporator Coils
For the first 30 seconds following unit start up, the
Hot Gas Solenoids in all zones are energized as
well as the Liquid Line Solenoid in Zone 1. This
sweeps refrigerant from the coils and returns it to
the compressor along with oil trapped in the
evaporators. High speed diesel operation is
delayed for 2 minutes after startup and the
alternator excitation output is delayed for 30
seconds after startup to reduce the load on the
engine.
To Next Page
Loading...
Need help?
General
