--- title: "Traulsen SN2: the coil sensor has failed" description: "What SN2 means on Traulsen SN2: the coil sensor has faileds, what to check before booking, and when it is not a failure at all." url: "https://commercialappliancerepair.center/error-codes/traulsen-sn2/" --- # Traulsen SN2: the coil sensor has failed The coil sensor tells the control when the evaporator has shed its frost during defrost. ## What SN2 actually means. The coil sensor tells the control when the evaporator has shed its frost during defrost. With SN2 showing, defrost timing is no longer guided by the coil, so frost and ice can build up. Traulsen marks SN2 as a service message. Traulsen commercial appliance display What to do when SN2 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 SN2 on its commercial appliances. Follow it to the end: the last card says whether this is a visit. 01 Keep logging food temperatures twice a shift. 02 Look through the grille for heavy frost on the coil and note what you see. 03 Book a visit before the coil ices over and airflow stops. ### 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 SN2 does not mean the cabinet is warm yet. It is also different from DEF ERR, which reports a defrost that did not finish. ## What you may notice with it. The commercial appliance problems SN2 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 - [**Walk-In Freezer Icing Up on the Coil, Floor and Door Frame**](https://commercialappliancerepair.center/problems/walk-in-freezer-icing-up/) - [**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 SN2 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/) [SN3](https://commercialappliancerepair.center/error-codes/traulsen-sn3/) [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 > SN2: Indicates coil 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) 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 SN2 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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Keep logging food temperatures twice a shift. If it comes back, it needs a visit. ### Why does my Traulsen show SN2 and frost on the coil? Without the coil sensor the control cannot tell when defrost is done, so ice can collect. The sensor needs replacing. ### Can I defrost a Traulsen by hand while I wait? Traulsen's control has a manual defrost setting under customer access. If you are not sure how, leave it and book a visit. ### Will SN2 on a Traulsen stop the unit? Not straight away. The risk grows as frost builds, so do not leave it for weeks. --- **[Read on the site: Traulsen SN2: the coil sensor has failed](https://commercialappliancerepair.center/error-codes/traulsen-sn2/)** **[Book a visit with CommercialApplianceRepair.center](https://commercialappliancerepair.center/schedule/)**