What It Means
- MS self-inspection error
- V33B: MS error in auto system-check mode
Lennox VRF / VRV
Lennox Error Code U4
VRF / VRV
U4 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
MS self-inspection error
13 models
V22B, V33B, VCFB, VHIB, VMDB, VOSB, VOWA, VRHC, VRHCVOS01-3P, VSCA, VSEA, VVCB, VWMB
Reheat coil (indoor), VRF indoor unit (indoor)
How it shows
- Indoor receiver display: U4
This manual entry does not list further causes or actions.
Applicable models & manual sources
- V22B
MS self-inspection error
V22B, V33B, VCFB, VHIB, VMDB, VOSB, VOWA, VVCB, VWMB
- V22B
MS self-inspection error
- V33B
MS self-inspection error
- VCFB
MS self-inspection error
- VHIB
MS self-inspection error
- VRHC
MS self-inspection error
VRHC, VRHCVOS01-3P
- VRHCVOS01-3P
MS self-inspection error
- VSCA
MS self-inspection error
VSCA, VSEA
- VSCA
MS self-inspection error
VSCA, VSEA
- VVCB
MS self-inspection error
- VVCB
MS self-inspection error
- VWMB
MS self-inspection error
MS error in auto system-check mode
Models: V33B
How it shows
- Indoor receiver display: U4
This manual entry does not list further causes or actions.
Applicable models & manual sources
- V33B
MS error in auto system-check mode
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.
