Trane

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 Trane YHC 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

YHC
Precedent high-efficiency G/E · Reliatel · under 15 t
Diagnose YHC — Sign in
YSC
Precedent packaged · Reliatel · 3–10 t class
Diagnose YSC — Sign in

Same number, other makers

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