Friedrich PTAC ZONEAIRE SELECT Service & Parts Manual page 61

Malfunction Analysis
Malfunction
"E4 indoor air outlet temperature sen-
sor failure/air blow out over
heat in electric heat mode"
E5 Outdoor coil temperature sensor
failure.
E8 Overheat protection/defrosting
E9 High pressure protection.
61
TROUBLESHOOTING
Possible Reasons
"Indoor air outlet temperature sensor
open circuit or short circuit;
Indoor filter gets dirty or something
blocks the air intake."
Outdoor coil temperature sensor open
circuit or short circuit
"Indoor fan failure/dirty filter/refrig-
erating system failure/indoor coil
temperature sensor failure"
"Outdoor fan failure/refrigerating sys-
tem failure/high pressure switch fail-
ure/outdoor coil temp sensor broken"
How to solve
"Check the sensor connection. If the
sensor is broken, replace with a new
one.Clean the filter and clean the air
way." See figures 703 and 704.
Check the sensor connection. If the
sensor broken, replace with a new one.
See figure 703.
Check the indoor fan/clean filter/refill
refrigerant/replace indoor coil sensor.
See figure 705 -710
"Check outdoor fan/refrigerating pipe
system/high pressure switch/outdoor
coil temp sensor."