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Emerson Electronic Unit Controller
(accessed through base side panel)
Note
: Self-Contained units only with Copeland Condensing units.
If equipped, Emerson Electronic Unit Controller (all models except the
ECSS40) has a low side pressure cut-out of 20 PSI and low side cut-in of
80 PSI, to protect the compressor from low pressure or low charge in the
system.
Pressure Control
If equipped (ECSS40SC only), Has a reset button that may be tripped due
to high head pressure or low pressure cut-out if the unit is low on
refrigerant.
Condenser Fan Is Wired To Run
100%
Do not assume the compressor is on because the condenser fan motor is
on, you must check power at the compressor as the condenser fan motor is
wired to run 100% of the time.
Head Pressure Too High
Check that the condenser coil is not restricted.
Check that the condenser filter is not restricted.
Check that condenser fan motor is working and the condenser fan is not
damaged.
Check that refrigerant is not overcharged.
Check the sub-cooling.
Check that the service valves are fully open.
Head Pressure Too Low
If equipped, check the sight glass for flashing
.
Check unit for refrigerant leaks.
Perform pump-down procedure to verify the valves are pumping.
Low Suction Pressure
If equipped, check
if sight glass is flashing or showing low charge.
Check that evaporator fan motors are working.
Check that the air flow is being directed through the evaporator coil. (All
interior panels and must be in place as well as the evaporator fan shroud.)
Check that the Evaporator Coil is clear of ice and debris.
High Suction Pressure
Check for refrigerant being overcharged.
Check for refrigeration restrictions.
Perform pump-down procedure to verity the valves are pumping.
Emerson Electronic Unit Controller
Errors
(DLL, DLT and HP)
If equipped, Emerson Electronic Unit Controller (all models except the
ECSS40) have an automatic pressure cutout. Any of the
D
ischarge
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ine
L
imit /
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ischarge
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ine
T
emperature or
H
igh
P
ressure alarm codes will lock
the compressor out of operation to protect it.
This is typically caused due to a restricted condenser coil or a restricted
condenser filter. Cycle power off to clean the obstruction, clean obstruction,
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20