Honeywell Home ERM5220R Guide D'installation page 14

Symptom
No outdoor
temperature shown
on thermostat
Thermostat shows "—"
for outdoor
temperature
Outdoor temperature
reading at thermostat
is too high
Compressor doesn't
turn on, "Y" LED is
blinking
Emergency backup
control doesn't
function
(if configured as
boiler)
33-00135EFS—11
Possible Cause
No wired outdoor
temperature sensor
connected to ERM, or
device configured as
boiler
Wired outdoor
temperature sensor
failed
Sun load on sensor
5-minute compressor
lockout after power
cycle
No valid indoor
temperature sensor
Action
Connect outdoor
temperature sensor
to S1/S1 terminals.
Device only reports
outdoor temperature
temperature when
configured as
compressor.
Check sensor for
short circuit or open
circuit.
Verify outdoor
temperature sensor is
not in direct sunlight.
May need to use
longer wire to mount
in ideal location.
Wait 5 minutes,
compressor will turn
on after safety
timeout.
Check sensor for
short circuit or open
circuit, or install
indoor temperature
sensor on S1/S1
terminals.
14