--- title: "Traulsen SN3: the liquid line sensor has failed" description: "What SN3 means on Traulsen SN3: the liquid line sensor has faileds, what to check before booking, and when it is not a failure at all." url: "https://commercialappliancerepair.center/error-codes/traulsen-sn3/" --- # Traulsen SN3: the liquid line sensor has failed Traulsen's R & A Series controls read a third sensor on the liquid line of the cooling system, which the control lists as its own readout. ## What SN3 actually means. Traulsen's R & A Series controls read a third sensor on the liquid line of the cooling system, which the control lists as its own readout. SN3 says that sensor is no longer giving a valid reading. It is a service message. Traulsen commercial appliance display What to do when SN3 shows on the commercial appliance ### Kind of code Sensors and probes A probe is handing the controller a reading it cannot trust, or none at all: a box or coil sensor torn loose from its clip, a fryer probe coated in carbon from oil left too long between filterings, a combi core probe with a kinked cable, or a connector gone green from steam and cleaning chemicals. The unit then runs on, stops, or shuts the heat or the cooling off to protect itself. Letting it cool and restarting it as the manual describes is fair; a probe that still reads wrong sits behind a panel, 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 Traulsen A Traulsen cabinet that starts to drift gets its visit as soon as the food inside has a safe place to go. ### Source Traulsen All Series quick reference guide, owner's manual TR35924 rev. C (2015), linked from traulsen.com owner's manuals Shown by the control on R & A Series cabinets, as listed in Traulsen's quick reference guide TR35924 (rev. C, 2015). Units built after July 2025 carry the Smart Control, which keeps alarms in a menu instead (see PFA). ## Before you book, in this order. Each step comes from Traulsen's own guidance for SN3 on its commercial appliances. Follow it to the end: the last card says whether this is a visit. 01 Check that the cabinet is still holding temperature and log it. 02 Keep the condenser clean and the doors closed so the system is not stressed while you wait. 03 Book a visit and mention SN3. ### 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 SN3 is not a refrigerant leak and not a cabinet temperature alarm. It concerns a sensor the control uses to watch the cooling side, so the box can still be cold. ## What you may notice with it. The commercial appliance problem SN3 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/) Problem ### Commercial Appliance Error Code on a Combi, Fryer, Dish Machine or Laundry Display 8 causes, cheapest first Where SN3 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/) ## Traulsen commercial appliances. A Traulsen cabinet that starts to drift gets its visit as soon as the food inside has a safe place to go. [Traulsen commercial appliance repair](https://commercialappliancerepair.center/brands/traulsen/) More Traulsen codes [ELE LOS](https://commercialappliancerepair.center/error-codes/traulsen-ele-los/) [DOR OPN](https://commercialappliancerepair.center/error-codes/traulsen-dor-opn/) [CHI](https://commercialappliancerepair.center/error-codes/traulsen-chi/) [CLO](https://commercialappliancerepair.center/error-codes/traulsen-clo/) [CLN FIL](https://commercialappliancerepair.center/error-codes/traulsen-cln-fil/) [SN1](https://commercialappliancerepair.center/error-codes/traulsen-sn1/) [SN2](https://commercialappliancerepair.center/error-codes/traulsen-sn2/) [DEF ERR](https://commercialappliancerepair.center/error-codes/traulsen-def-err/) [RUN ERR](https://commercialappliancerepair.center/error-codes/traulsen-run-err/) [PFA](https://commercialappliancerepair.center/error-codes/traulsen-pfa/) Sensors and probes on other makes [Alto-Shaam E20](https://commercialappliancerepair.center/error-codes/alto-shaam-e20/) [Beverage-Air E01](https://commercialappliancerepair.center/error-codes/beverage-air-e01/) [Blodgett Cavity Probe Error](https://commercialappliancerepair.center/error-codes/blodgett-cavity-probe-error/) [Continental Refrigerator E0](https://commercialappliancerepair.center/error-codes/continental-refrigerator-e0/) [Delfield E01](https://commercialappliancerepair.center/error-codes/delfield-e01/) [Dexter TEMP SENSOR SHORT](https://commercialappliancerepair.center/error-codes/dexter-temp-sensor-short/) [Frymaster E13](https://commercialappliancerepair.center/error-codes/frymaster-e13/) [Garland E21](https://commercialappliancerepair.center/error-codes/garland-e21/) [All 60 codes of this kind](https://commercialappliancerepair.center/error-codes/#family-sensor) Traulsen 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. Traulsen 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 Traulsen's own words > SN3: Indicates liquid line sensor has failed.* [Traulsen All Series quick reference guide, owner's manual TR35924 rev. C (2015), linked from traulsen.com owner's manuals](https://cdn2.webdamdb.com/md_JHTi7CKsiksA.jpg.pdf?1487671030) [Traulsen All Series quick reference guide, owner's manual TR35924 rev. C (2015), linked from traulsen.com owner's manuals](https://cdn2.webdamdb.com/md_JHTi7CKsiksA.jpg.pdf?1487671030) Every code on this site is taken from the manufacturer's documentation, never from a forum or a parts listing. Shown by the control on R & A Series cabinets, as listed in Traulsen's quick reference guide TR35924 (rev. C, 2015). Units built after July 2025 carry the Smart Control, which keeps alarms in a menu instead (see PFA). ## Traulsen SN3 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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Check that the cabinet is still holding temperature and log it. If it comes back, it needs a visit. ### Is my Traulsen still safe to use with SN3? Often yes, as long as the food stays cold. Watch the log and book a visit so the sensor is replaced. ### What does the liquid line sensor do on a Traulsen? It gives the control a temperature reading from the cooling system itself, separate from the cabinet air and the coil. ### Can I see the sensor readings on a Traulsen control? Traulsen lists cabinet air, coil and liquid line sensor readouts in the customer access menu of R & A Series controls. --- **[Read on the site: Traulsen SN3: the liquid line sensor has failed](https://commercialappliancerepair.center/error-codes/traulsen-sn3/)** **[Book a visit with CommercialApplianceRepair.center](https://commercialappliancerepair.center/schedule/)**