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measured a temperature above 268 F (131 C) or the thermistor has
short circuited (jumpered out).
The DSC will de--energize the compressor contactor and unloader
solenoid, and the alarm relay contacts will close causing a T051
alert on the ComfortLink Control.
The compressor will be
allowed to restart after 30 minute delay and after the DTT reads
below 250 F (120 C). The flash code and alarm relay contacts will
be reset after the compressor has run for 60 minutes without any
other ALERTs.
If five discharge temperature ALERTs have
occurred within four hours, the DSC will lock out the compressor.
The lockout can only be reset by cycling the 24VAC power off and
on.
Flash Code 3
⎯
Compressor Protector Trip
This occurs when the demand signal from the system controller is
greater than 1.44VDC and there is no compressor current detected.
This could be due to the compressor’s internal overload protector
being open, fuse or breaker open, power disconnected to
compressor contactor, compressor power wiring not run through
DSC current transformer port or a compressor contactor failure.
The DSC will de--energize the compressor contactor and unloader
solenoid and the alarm relay contacts will close causing a T051
alert on the ComfortLink Control. The DSC will wait for the two
minute anti--short cycle timer to time out and if the system
controller demand signal is still greater than 1.44VDC, energize the
compressor contactor again. If compressor current is detected on
the restart, the ALERT code and alarm relay output will reset. The
DSC will attempt to restart compressor as long as the system
controller demand is above 1.44VDC. There is no lockout feature
for this ALERT.
Flash Code 4
⎯
Locked Rotor
A locked rotor condition in the compressor is sensed by the DSC
on four consecutive start ups. The DSC will de--energize the
compressor contactor and unloader solenoid and the alarm relay
contacts will close causing a T051 alert on the ComfortLink
Control. This code results in a lockout and can only be reset by
cycling the 24VAC power off and on.
Flash Code 5
⎯
Demand Signal Loss
This occurs when the demand signal input has dropped below
0.5VDC. The demand input signal wire may be disconnected or
the system controller providing the signal may not be powered.
The DSC will de--energize the compressor contactor and unloader
solenoid and the alarm relay contacts will close causing a T051
alert on the ComfortLink Control. Once the system controller
demand signal input has risen above 0.5VDC, the ALERT code
and alarm relay output will reset. If the demand signal is above
1.44VDC and the anti--short cycle timer has timed out, the
compressor will restart.
Flash Code 6
⎯
Discharge Thermistor Fault
This occurs when the DSC is not receiving a signal from the
discharge temperature thermistor (DTT). The thermistor may be
missing, disconnected or a wire broken. The alarm relay contacts
will close and the DSC will not increase the capacity of the
compressor beyond 50% loading. This ALERT code and alarm
relay output are reset by reconnecting the DTT.
Flash Code 7
⎯
Reserved for future use
Flash Code 8
⎯
Compressor Contactor Fault
This occurs when the compressor current is detected when the
system controller demand signal is below 1.44VDC. The
compressor contactor may have welded contacts or the contacts
may be mechanically jammed. The compressor will continue to run
in this condition since the DSC cannot open the compressor
contactor. The DSC will energize the compressor contactor and the
alarm relay contacts will close causing a T051 alert on the
ComfortLink Control. The unloader solenoid will remain
energized causing the compressor to run unloaded as long as the
system controller demand signal is less than 1.44VDC. If the
system controller demand is greater than 1.44VDC, the unloader
solenoid will de--energize causing the compressor to run loaded.
The ALERT code and alarm relay output are reset when current is
no longer detected while system controller demand signal is below
1.44VDC.
Flash Code 9
⎯
Low 24VAC Supply
This occurs when the supply voltage to the DSC has dropped
below 18.5VDC.
The DSC will de--energize the compressor
contactor and unloader solenoid. The alarm relay contacts may
close if the voltage is high enough for the alarm relay to pull in.
The ALERT code and alarm relay output are reset when the supply
voltage to the DSC rises above 19.5VAC.
Table 10 — DSC Red LED Flash Codes
LED Flash
Code
Description
Action Taken
by Control
Reset
Method
Probable Cause
1
Flash
Reserved for Future Use
N/A
N/A
N/A
2
Flash
High Discharge Temperature
Compressor
shutdown
Automatic
Compressor discharge temperature is greater then 268
degrees F or the DTT is shorted.
3
Flash
Compressor Protector Trip
Compressor
shutdown
Automatic
Compressor’s internal overload protector being open,
fuse or breaker open, power disconnected to compres-
sor contactor, compressor power wiring not run through
DSC current transformer port or a compressor contactor
failure.
4
Flash
Locked Rotor
Compressor
lockout
Manual
Four consecutive start ups with locked rotor.
5
Flash
Demand Signal Loss
Compressor
shutdown
Automatic
Signal wire may be disconnected or the system control-
ler providing the signal may not be powered
6
Flash
Discharge Thermistor Fault
Capacity Limited
Automatic
DTT may be missing, disconnected or a wire broken
7
Flash
Reserved for Future Use
N/A
N/A
N/A
8
Flash
Compressor Contactor Fault
Keep capacity
at 15%
Automatic
Compressor contactor may have welded contacts or the
contacts may be mechanically jammed
9
Flash
Low 24VAC Supply
Compressor
shutdown
Automatic
Bad connection or transformer.
48/
50P
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