True uLi: the supply voltage is too low
The Danfoss controls True fits watch the line voltage and warn when it sags below their limit.
Mon–Sat, 8am–8pm
- Controls and power
- Commercial controls and board repair
- Source: True Residential
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What uLi
actually means.
The Danfoss controls True fits watch the line voltage and warn when it sags below their limit. Low voltage makes a compressor struggle to start and run hot. The problem is usually on the building side: a long extension cord, a shared circuit or a weak outlet.
True Residential commercial appliance display · also shown as uLo, Ulo
What to do when uLi shows on the commercial applianceKind of codeControls and power
The controller itself is reporting trouble, or the supply behind it is: a display with dead segments, a keypad that stopped responding after steam or degreaser got behind it, relays that stick, stored recipes or cycles that vanished overnight, a blown control fuse, or one leg of a three-phase feed missing so half the heat or the pump is gone. A full power cycle at the breaker, done as the manual describes, clears a passing glitch; a code that returns, a scorched smell or any sign of moisture behind the panel means the breaker stays off, and that is a visit.
Usually leads toCommercial controls and board repair
Controllers, touch panels, relays, contactors and interlocks tested, and replaced only when the evidence says so.
Shows up asCommercial Appliance Error Code on a Combi, Fryer, Dish Machine or Laundry Display
A commercial appliance error code appears as letters or numbers on a combi, fryer, reach-in controller, dish machine or laundry machine display, or as a flashing light or an alarm tone.
MakeTrue Residential
A True cooler or prep station in a restaurant is looked at once the kitchen confirms where the held food is sitting for now.
SourceTrue Commercial Refrigeration General Control Guide, P#811072, rev. C (09/2025)
uLi or uLo (Danfoss ERC) and Ulo (Danfoss ETC) are listed as low voltage alarms in True's general control guide (rev. C, 2025).
Before you book,
in this order.
Each step comes from True Residential's own guidance for uLi on its commercial appliances. Follow it to the end: the last card says whether this is a visit.
Make sure the unit is plugged straight into its own outlet and not into an extension cord or power strip.
Ask whether other heavy equipment on the same circuit started at the same time the message appeared.
If uLi stays after those checks, have an electrician check the circuit and book a visit for the unit.
Still there?
It usually turns into commercial controls and board repair. Book with the code and the model number.
What not to do
uLi is not a failure of the control. Its opposite, uHi or UHi, warns of high voltage and has the same first checks.
What you may
notice with it.
The commercial appliance problems uLi tends to arrive with. Answer these at the commercial appliance before anyone is booked.
All problems
Where uLi usually leads
Commercial controls and board repair.
True Residential
commercial appliances.
A True cooler or prep station in a restaurant is looked at once the kitchen confirms where the held food is sitting for now.
True Residential commercial appliance repairMore True Residential codes
All 14 True Residential codesControls and power on other makes
Commercial cold storage
Reach-in and pass-through cabinets, walk-in coolers and walk-in freezers, prep and sandwich tables, undercounter units and blast chillers that hold a kitchen's food at safe temperatures.
Commercial cooking equipment
Fryers, griddles, charbroilers, restaurant ranges, convection and combi ovens, steamers, kettles, holding cabinets and toasters, on gas or electric, that make up the hot side of a kitchen line.
In True Residential's own words
uLi or uLo Low voltage alarm
Every code on this site is taken from the manufacturer's documentation, never from a forum or a parts listing. uLi or uLo (Danfoss ERC) and Ulo (Danfoss ETC) are listed as low voltage alarms in True's general control guide (rev. C, 2025).
True Residential uLi commercial appliance repair,
where we come out.
The same visit in every metro below: the code, the model number, and a diagnosis before any part is ordered.
All service areasTampa BayFL · 31 areas
Miami / South FloridaFL · 47 areas
New York MetroNY · 75 areas
HoustonTX · 36 areas
ChicagoIL · 50 areas
Los AngelesCA · 95 areas
San DiegoCA · 31 areas
Questions
about uLi.
Can I clear uLi myself?
Why does my True show uLi only at lunch?
Can low voltage damage my True?
Is uHi the same problem on a True?
Back to your everyday
Still showing uLi?
A booking with a code goes further when it has the code as shown, the model and serial from the data plate, and a word on whether the unit still holds temperature, heats, rinses or spins. With those three, the office can match the likely part to your unit the same day.