Lennox

Uv

Lockout

Uv / LU — undervoltage

Keypad example: Uv (Yaskawa) or LU. DC bus dropped. Incoming power or a missing phase.

2 plates — walk the one on the cabinet

First check

1 Read the drive before you cycle power

On Lennox LGH photograph the VFD keypad or the unit-board fan alarm (OC, LU, OU, GF, OH, limp). Power-cycle wipes what you needed. Three legs at the drive line terminals, under load. A single-phased 3-phase drive nuisances Uv / oC.

Expect: Live drive code written down. Line voltage at L1/L2/L3 of the drive.

The rest of the walkthrough is Diagnose.

On the plates

Three legs at the drive line terminals, under load. A single-phased 3-phase drive nuisances Uv / oC.
Do not ignore Uv on a 480 V roof with a 208 V drive, or the reverse.

Plates that use Uv

LGH
Landmark packaged G/E · Prodigy · 3–15 t
Diagnose LGH — Sign in
LGT
Enlight / Model L packaged · under 15 t
Diagnose LGT — Sign in

Same number, other makers

Uv on Lennox is not the same code on these plates.