E8: Compressor High Temperature Protection. Low Indoor Airflow.
Safety Note: Before any component is electrically disconnected in the unit, shut off the main power. Inverter board DC bus voltage can take up to 15 minutes to discharge.
Caution: Do not plug or unplug components while electrical power is present, as this can damage the equipment and control boards.
E8 IS HIGH TEMPERATUE PROTECTION, PRIMARILY IN HEATING MODE INDICATING HIGH INDOOR COIL TEMPERATURE OR COIL SENSOR (THERMISTOR) READING INCORRECTLY.
E8 TROUBLESHOOTING STEPS:
Step 1: Evaluate the installation
Don't overlook the obvious. Check that indoor filters, coils, and blower wheel are clean. Ensure the unit has adequate space for airflow.
For MULTI-zone units, verify that wiring and linesets match the correct ports outside for each indoor unit. Check if additional charge was required.
DISCONNECT POWER FROM UNIT
Step 2: Check indoor coil temperatue sensor and indoor ambient sensor.
If the indoor coil sensor is reading out of range (low resistance indicating high temperature), the system may interpret it as high indoor coil temperature in heating mode.
RESTORE POWER TO UNIT
Step 3: Turn system on in Fan mode
Check that the indoor fan operates, and there is adequate airflow.
Before moving on to the next steps, collect and record all data, including temperatures, pressures, charge amounts, outdoor ambient, indoor ambient, voltages, ohm readings, etc.
TURN SYSTEM ON IN HEAT MODE
Step 4: Check that the indoor and outdoor units come on and operate and perform Delta T measurments on indoor unit(s)
Verify there is a call for heat by adjusting the set point above indoor ambient using the remote control. Confirm HEAT mode on the remote. In heating mode, if high pressures or improper Delta T are observed, proceed to Step 6.
IF OUTDOOR AMBIENT ALLOWS AND IT IS HELPFUL, TEST IN COOLING MODE
Step 5: Check that the indoor and outdoor units come on and operate and perform Delta T measurments on indoor unit(s).
Verify there is a call for cool by adjusting the set point below indoor ambient using the remote control. Confirm COOL mode on the remote. In cooling mode, if Delta T or low pressures are observed, there may be a restriction. If high pressures are observed, perform Step 6.
Step 6: If previous steps have not identified the problem verify proper refrigerant charge.
If improper Delta T and pressures were observed, recover and weigh out the charge. Perform a triple evacuation using dry nitrogen and vacuum below 300 microns before weighing the proper charge into the system. Repeat Steps 4 and/or 5 to check Delta T.
Step7: If a restriction is suspected perform a 4 point temperature check.
Step8: If the 4 point temperature check did not reveal the restriction then the restriction could be internal to the equipment.
The restriction could be internal to the equipment, requiring temperature drops across components like Electronic Expansion valve(s), capillary tubes, 4-way valve (Reversing Valve), strainers, accumulators, and coils. If guidance is needed, reach out to our Team of Technical Support Advisors.