Manufacturer reserves the right to change specifications or designs without notice.
10.2019
ESI (Ultra) Service Manual
55/68
1.
Error definition and method to check:
H1: The detected ambient temperature is absolutely prohibited for cooling.
TA<32
°
F or ≥140
°
F
H2: The detected ambient temperature is absolutely prohibited for heating.
TA ≥ 86
°
F or TA< forced heating stop temperature set by n01
2.
Possible causes:
The ambient temperature exceeds the set range of operation.
The system is running previous mode
Damaged ambient temperature sensor (TA)
Damaged main control board.
NO
Is the outside temperature within the range of operation
Check whether there are other heat sources around TA sensor
Display
or
Ambient temperature limit operation
NO
Check whether the ambient temperature sensor (TA) is seated to
the specified location and connected to
CN2
of PCB.
NO
YES
Turn off the power supply, unplug TA sensor to check if the
resistance is in the range of
Temperature sensor A
. *
NOTE
NO
YES
Replace the main control board
Replace the sensor
Reconnect the sensor
YES
Cool/Heat
has been selected from thermostat?
Is the unit running heating mode but the thermostat switches to
cooling mode, or the unit running cooling mode but the thermostat
switches to heating mode at that time.
YES
NO
YES
The unit will respond to mode
switch after 6 minutes’ stop.
Remove other heat sources
It’s normal control to protect the
system.