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The open door of a cold stainless combi oven in a commercial kitchen, its empty racks in view and a thin core temperature probe hanging on its holder inside the cavity, nobody at the combi oven.

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.

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Mon–Sat, 8am–8pm

  • Sensors and probes
  • Commercial controls and board repair
  • Source: Traulsen

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Three short steps, about a minute.

or call (844) 571-4566

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 codeSensors 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 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.

MakeTraulsen

A Traulsen cabinet that starts to drift gets its visit as soon as the food inside has a safe place to go.

SourceTraulsen 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. 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

Before you call

Commercial Appliance Error Code on a Combi, Fryer, Dish Machine or Laundry Display

All 8 causes, cheapest first
Close view of the dark touch control panel on the front of a stainless combi oven in a commercial kitchen, one abstract amber warning indicator glowing among unlit icons, the steam-fogged glass door blurred beside it. 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

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

More Traulsen codes

ELE LOSDOR OPNCHICLOCLN FILSN1SN2DEF ERRRUN ERRPFA

Sensors and probes on other makes

Alto-Shaam E20Beverage-Air E01Blodgett Cavity Probe ErrorContinental Refrigerator E0Delfield E01Dexter TEMP SENSOR SHORTFrymaster E13Garland E21
All 60 codes of this kind
A row of three stainless steel reach-in cabinets with solid doors along the wall of a working restaurant kitchen, the reach-ins clearly the subject, one door open showing sheet pans of prepped vegetables on wire shelves, a walk-in cooler door with a clear strip curtain visible at the far end, a cook seen only from behind in a white jacket passing in the soft background, bright even kitchen light. 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.

 A working restaurant cooking line under a stainless ventilation hood, two stainless gas fryers with baskets hanging above the oil, a flat griddle and a combi oven with a glass door beside them, the equipment clearly the subject, a cook seen only from behind and shoulders down at the far end of the line, warm kitchen light, small blue flames visible under the griddle. 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 Traulsen All Series quick reference guide, owner's manual TR35924 rev. C (2015), linked from traulsen.com owner's manuals

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.

All service areas

Tampa BayFL · 31 areas

OrlandoFL · 30 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

San Francisco Bay AreaCA · 74 areas

A restaurant team working a busy commercial kitchen line.
For the heart of your home.

Questions
about SN3.

Can I clear SN3 myself?
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.

Back to your everyday

Still showing SN3?

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.

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