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Diagnostics
The Friedrich Smart Center continuously monitors the PTAC unit
operation and will store service codes if certain conditions are
witnessed. In some cases the unit may take action and shut the
unit off until conditions are corrected.
To access the error code menu press the ‘Heat’ and ‘High Fan’
buttons simultaneously for three seconds. If error codes are
present they will be displayed. If multiple codes exist you can
toggle between messages using the temp button. To clear
all codes press the temp button for three seconds while in
the error code mode. To exit without changing codes press the
‘Low Fan’ button.
Error
Code
Code Translation Action Taken by Unit Possible Cause
01
NOT USED NONE
02
An extreme low voltage condition
exists <198V for 230V units and
<239V for 265V units.
Shut down unit. Display Error code and fl ash.
Once voltage rises to normal level system power
is restored.
• Inadequate power supply
• Defective breaker
• Blown fuse
03
Return air thermistor sensor open
or short circuit
Set return air sensor = 75
°F. Alternate fl ash set
point and error code. Leave unit running.
• Defective sensor
04
Indoor coil thermistor sensor open
Or short circuit
Set ID coil temp = 40
°F. Alternate fl ash set point
and error code. Leave unit running.
• Defective sensor
05
Outdoor coil thermistor sensor
open Or short circuit
Set OD coil temp = 20
°F. Alternate fl ash set point
and error code. Automatically change over to
Electric heat Mode only. Leave unit running.
• Defective sensor
06
If O.D. coil Temperature > 175 Deg
F for 2 consecutive minutes. (Heat
Pump models only)
Alternate fl ash set point and error code. Shut unit
down for 5 minutes, then try again 2 times, if fails
the 3rd time, then shut down unit.
• Dirty coil
• Fan motor failure
• Restricted air fl ow
• Non-condensables in
refrigeration system
07
I.D coil temperature <30 Deg F for
2 consecutive minutes.
Alternate fl ash set point and error code. Continue
fan operation while the compressor is locked out
until the indoor coil thermistor reaches 45° F, and
then energize the compressor. However, com-
pressor must still wait a lockout time of 180 to 240
seconds.
• Dirty fi lters
• Dirty coil
• Fan motor failure
• Restricted airfl ow
• Improper refrigerant charge
• Restriction in refrigerant circuit
10
Room Freeze Protection triggered
Alternate fl ash set point and error code. Keep unit
running.
• Room temperature fell below 40°F
Test Mode
For service and diagnostic use only, the built-in timers and
delays on the PTAC may be bypassed by pressing the ‘Cool’
and ‘Low Fan’ buttons simultaneously for three seconds while
in any mode to enter the test mode.
TE
will be displayed when
entering test mode, and
DE
will be displayed when exiting. The
test mode will automatically be exited 30 minutes after entering it
or by pressing the ‘Cool’ and ‘Low Fan’ buttons simultaneously
for three seconds.
Digital Control Diagnostics and Test Mode
The chart below lists the possible error codes and their description: