Honeywell ERM5220R1018 - Page 15

15 33-00135EFS—05
No outdoor
temperature shown on
thermostat
No wired outdoor
temperature sensor
connected to ERM, or
device configured as
boiler
Connect outdoor
temperature sensor to
S1/S1 terminals.
Device only reports
outdoor temperature
temperature when
configured as
compressor.
Thermostat shows “—”
for outdoor
temperature
Wired outdoor
temperature sensor
failed
Check sensor for short
circuit or open circuit.
Outdoor temperature
reading at thermostat
is too high
Sun load on sensor Verify outdoor
temperature sensor is
not in direct sunlight.
May need to use
longer wire to mount in
ideal location.
Compressor doesn’t
turn on, “Y” LED is
blinking
5-minute compressor
lockout after power
cycle
Wait 5 minutes,
compressor will turn
on after safety timeout.
Emergency backup
control doesn’t function
(if configured as boiler)
No valid indoor
temperature sensor
Check sensor for short
circuit or open circuit,
or install indoor
temperature sensor on
S1/S1 terminals.
Symptom Possible Cause Action
33-00135EFS_C.book Page 15 Monday, May 2, 2016 1:52 PM