What It Means
- VHEC***S4-4P, VHTC***S4-4P: Error on room temperature sensor of Hydro unit / Hydro unit HT (Short or Open)
- V36C***S4-4P: Open or short circuit error of the indoor-temperature sensor
Lennox VRF / VRV
Lennox VRF / VRV Error Code E121
VRF / VRV
E121 means different things on different VRF / VRV models. Enter your model number to see only your reading, or find your model below.
Causes & actions from Lennox
Error on room temperature sensor of Hydro unit / Hydro unit HT (Short or Open)
Models: VHEC***S4-4P, VHTC***S4-4P
Hydro unit (indoor)
How it shows
- hydro main pcb display: E121
- hydro wired controller display: E121
This manual entry does not list further causes or actions.
Applicable models & manual sources
- VHEC***S4-4P
Error on room temperature sensor of Hydro unit / Hydro unit HT (Short or Open)
VHEC***S4-4P, VHTC***S4-4P
Open or short circuit error of the indoor-temperature sensor
Models: V36C***S4-4P
VRF indoor unit (indoor)
How it shows
- vrf 360 fault code: E121
- vrf 360 indoor indicator: ice_blue: off, yellow_green: off, blue: off, red: flashing (blue: off, ice_blue: off, red: flashing, yellow_green: off)
This manual entry does not list further causes or actions.
Applicable models & manual sources
- V36C***S4-4P
Open or short circuit error of the indoor-temperature sensor
Disclaimer: This information is for general reference. Code wording and instructions vary by model. Always follow the service manual for your exact unit.
What should you check next?
Continue in ACLogics with guided diagnosis for your equipment and symptoms.
