--- title: "True uLi: the supply voltage is too low" description: "What uLi means on True uLi: the supply voltage is too lows, what to check before booking, and when it is not a failure at all." url: "https://commercialappliancerepair.center/error-codes/true-uli/" --- # 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. ## 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 appliance ### Kind of code Controls 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 to Commercial controls and board repair Controllers, touch panels, relays, contactors and interlocks tested, and replaced only when the evidence says so. ### Shows up as Commercial 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. ### Make True 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. ### Source True 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. 01 Make sure the unit is plugged straight into its own outlet and not into an extension cord or power strip. 02 Ask whether other heavy equipment on the same circuit started at the same time the message appeared. 03 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](https://commercialappliancerepair.center/services/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](https://commercialappliancerepair.center/problems/) Before you call ### [Commercial Appliance Error Code on a Combi, Fryer, Dish Machine or Laundry Display](https://commercialappliancerepair.center/problems/commercial-error-code/) [All 8 causes, cheapest first](https://commercialappliancerepair.center/problems/commercial-error-code/) It also comes with - [**Reach-In Cooler Not Holding Temperature Through a Shift**](https://commercialappliancerepair.center/problems/reach-in-not-holding-temperature/) Problem ### Commercial Appliance Error Code on a Combi, Fryer, Dish Machine or Laundry Display 8 causes, cheapest first Where uLi usually leads ## Commercial controls and board repair. **Controller, touch panel, probe or sensor, relay, contactor, power supply, door switch or interlock, tested before anything is changed · moderate.** Book a visit [What the job involves](https://commercialappliancerepair.center/services/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 repair](https://commercialappliancerepair.center/brands/true/) More True Residential codes [HI](https://commercialappliancerepair.center/error-codes/true-hi/) [LO](https://commercialappliancerepair.center/error-codes/true-lo/) [dOr](https://commercialappliancerepair.center/error-codes/true-dor/) [dEF](https://commercialappliancerepair.center/error-codes/true-def/) [HA](https://commercialappliancerepair.center/error-codes/true-ha/) [P1](https://commercialappliancerepair.center/error-codes/true-p1/) [P2](https://commercialappliancerepair.center/error-codes/true-p2/) [E01](https://commercialappliancerepair.center/error-codes/true-e01/) [Con](https://commercialappliancerepair.center/error-codes/true-con/) [LEA](https://commercialappliancerepair.center/error-codes/true-lea/) [EoC](https://commercialappliancerepair.center/error-codes/true-eoc/) [EE](https://commercialappliancerepair.center/error-codes/true-ee/) [All 14 True Residential codes](https://commercialappliancerepair.center/error-codes/#codes-true) Controls and power on other makes [Alto-Shaam E02](https://commercialappliancerepair.center/error-codes/alto-shaam-e02/) [Beverage-Air uLi](https://commercialappliancerepair.center/error-codes/beverage-air-uli/) [Blodgett Com Error](https://commercialappliancerepair.center/error-codes/blodgett-com-error/) [Delfield uLi](https://commercialappliancerepair.center/error-codes/delfield-uli/) [Dexter F1](https://commercialappliancerepair.center/error-codes/dexter-f1/) [Frymaster E19](https://commercialappliancerepair.center/error-codes/frymaster-e19/) [Garland E01](https://commercialappliancerepair.center/error-codes/garland-e01/) [Hatco Communication Error](https://commercialappliancerepair.center/error-codes/hatco-communication-error/) [All 63 codes of this kind](https://commercialappliancerepair.center/error-codes/#family-board) True Residential builds this ### 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. True Residential builds this ### 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 [True Commercial Refrigeration General Control Guide, P#811072, rev. C (09/2025)](https://www.truemfg.com/wp-content/uploads/2025/09/811072_Commercial-Refrigeration-General-Control-Guide_REV_C_EN.pdf) [True Commercial Refrigeration General Control Guide, P#811072, rev. C (09/2025)](https://www.truemfg.com/wp-content/uploads/2025/09/811072_Commercial-Refrigeration-General-Control-Guide_REV_C_EN.pdf) 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. 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Make sure the unit is plugged straight into its own outlet and not into an extension cord or power strip. If it comes back, it needs a visit. ### Why does my True show uLi only at lunch? At peak hours other equipment draws heavily on the same supply, and voltage dips. A dedicated circuit usually solves it. ### Can low voltage damage my True? Repeated starts on low voltage stress the compressor. That is why the control warns you. ### Is uHi the same problem on a True? It is the opposite: voltage above the control's limit. Both call for an electrician to measure the circuit. --- **[Read on the site: True uLi: the supply voltage is too low](https://commercialappliancerepair.center/error-codes/true-uli/)** **[Book a visit with CommercialApplianceRepair.center](https://commercialappliancerepair.center/schedule/)**