---
title: "Alto-Shaam E109: the high-limit safety switch has opened"
description: "What E109 means on Alto-Shaam E109: the high-limit safety switch has openeds, what to check before booking, and when it is not a failure at all."
url: "https://commercialappliancerepair.center/error-codes/alto-shaam-e109/"
---

# Alto-Shaam E109: the high-limit safety switch has opened

The high-limit switch is a safety device that cuts heating if the oven gets too hot.

## What E109 actually means.

The high-limit switch is a safety device that cuts heating if the oven gets too hot. E109 is called out when its input to the control board is open. The manual lists an overheat, a failed cooling fan, a stuck heat relay, or wiring and switch trouble.

Alto-Shaam commercial appliance display

What to do when E109 shows on the commercial appliance

### Kind of code Temperature and alarms

The controller has seen a temperature outside the band it was set for and is saying so: a box above its alarm point, a fryer vat or an oven cavity that tripped its high-limit, or a dish machine rinse that never came up to heat. Often the cause sits outside the unit, such as a door left open during a delivery, a coil packed with grease, a kitchen far hotter than the maker allows or a booster fed cold water. Checking the door, the coil and the air around the unit is fair; move the product if a cold box stays above 41°F, and book the visit.

### Usually leads to Reach-in and prep table repair

Reach-ins, pass-throughs, prep tables and blast chillers: gaskets, hinges, fans, thermostats, condensers and compressors.

### 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 Alto-Shaam

An Alto-Shaam call is usually booked for the hours between the last plate and the prep crew, so the cabinet can cool and the tech can open it without holding up service.

### Source Alto-Shaam Combitherm CT PROformance Series operator's manual, MN-35948 Rev 21 (10/21) (Wayback copy)

Combitherm CT PROformance (CTP) combi ovens, error code table in operator's manual MN-35948 Rev 21.

## Before you book, in this order.

Each step comes from Alto-Shaam's own guidance for E109 on its commercial appliances. Follow it to the end: the last card says whether this is a visit.

01

Let the oven cool fully with the door closed.

02

Press the high-limit reset switch once, as the manual instructs, and no more.

03

If E109 remains, book a visit; the cause of the overheat has to be found.

### Still there?

It usually turns into [reach-in and prep table repair](https://commercialappliancerepair.center/services/reach-in-and-prep-table-repair/). Book with the code and the model number.

### What not to do

E109 is not the relay board overheating, which is E02 or E108. It is also not a probe failure; the switch works independently of the temperature probes.

## What you may notice with it.

The commercial appliance problems E109 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

- [**Restaurant Equipment Burning Smell: Scorched Oil, Hot Wiring or Lint**](https://commercialappliancerepair.center/problems/commercial-burning-smell/)

Problem

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

8 causes, cheapest first

Where E109 usually leads

## Reach-in and prep table repair.

**Reach-in, pass-through or prep table gasket, hinge, fan motor, thermostat or controller, defrost heater, leak repair or compressor · moderate.**

Book a visit [What the job involves](https://commercialappliancerepair.center/services/reach-in-and-prep-table-repair/)

## Alto-Shaam commercial appliances.

An Alto-Shaam call is usually booked for the hours between the last plate and the prep crew, so the cabinet can cool and the tech can open it without holding up service.

[Alto-Shaam commercial appliance repair](https://commercialappliancerepair.center/brands/alto-shaam/)

More Alto-Shaam codes

[E01](https://commercialappliancerepair.center/error-codes/alto-shaam-e01/) [E02](https://commercialappliancerepair.center/error-codes/alto-shaam-e02/) [E03](https://commercialappliancerepair.center/error-codes/alto-shaam-e03/) [E13](https://commercialappliancerepair.center/error-codes/alto-shaam-e13/) [E20](https://commercialappliancerepair.center/error-codes/alto-shaam-e20/) [E21](https://commercialappliancerepair.center/error-codes/alto-shaam-e21/) [E34](https://commercialappliancerepair.center/error-codes/alto-shaam-e34/) [E36](https://commercialappliancerepair.center/error-codes/alto-shaam-e36/) [E57](https://commercialappliancerepair.center/error-codes/alto-shaam-e57/) [E89](https://commercialappliancerepair.center/error-codes/alto-shaam-e89/) [E92](https://commercialappliancerepair.center/error-codes/alto-shaam-e92/) [E100](https://commercialappliancerepair.center/error-codes/alto-shaam-e100/)

[All 15 Alto-Shaam codes](https://commercialappliancerepair.center/error-codes/#codes-alto-shaam)

Temperature and alarms on other makes

[Beverage-Air Hi](https://commercialappliancerepair.center/error-codes/beverage-air-hi/) [Blodgett Cavity High Temp Error](https://commercialappliancerepair.center/error-codes/blodgett-cavity-high-temp-error/) [Cleveland RESET light](https://commercialappliancerepair.center/error-codes/cleveland-reset-light/) [Continental Refrigerator HI](https://commercialappliancerepair.center/error-codes/continental-refrigerator-hi/) [Delfield Hi](https://commercialappliancerepair.center/error-codes/delfield-hi/) [Frymaster E16](https://commercialappliancerepair.center/error-codes/frymaster-e16/) [Garland E04](https://commercialappliancerepair.center/error-codes/garland-e04/) [Hatco Control Board Overtemp](https://commercialappliancerepair.center/error-codes/hatco-control-board-overtemp/)

[All 70 codes of this kind](https://commercialappliancerepair.center/error-codes/#family-temperature)

Alto-Shaam 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.

Alto-Shaam 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 Alto-Shaam's own words

> Press the high-limit reset switch only once.

[Alto-Shaam Combitherm CT PROformance Series operator's manual, MN-35948 Rev 21 (10/21) (Wayback copy)](https://web.archive.org/web/20220509173647/https://www.alto-shaam.com/en/media-library/widen-assets/technical-literature/operators-manual/operators-manual_combitherm_ctp_mn-35948-en-18-pdf.pdf) [Alto-Shaam Combitherm CT PROformance Series operator's manual, MN-35948 Rev 21 (10/21) (Wayback copy)](https://web.archive.org/web/20220509173647/https://www.alto-shaam.com/en/media-library/widen-assets/technical-literature/operators-manual/operators-manual_combitherm_ctp_mn-35948-en-18-pdf.pdf)

Every code on this site is taken from the manufacturer's documentation, never from a forum or a parts listing. Combitherm CT PROformance (CTP) combi ovens, error code table in operator's manual MN-35948 Rev 21.

## Alto-Shaam E109 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](https://commercialappliancerepair.center/locations/)

[Tampa Bay](https://commercialappliancerepair.center/locations/tampa-bay/) FL · 31 areas

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For the heart of your home.

## Questions about E109.

### Can I clear E109 myself?

Let the oven cool fully with the door closed. If it comes back, it needs a visit.

### How many times can I reset E109 on an Alto-Shaam?

Once. The manual says to press the high-limit reset switch only once and contact service if the condition remains.

### What trips the high limit on an Alto-Shaam combi?

An overheat, often from a failed cooling fan or a heat relay stuck closed. A technician finds which it was.

### Is E109 on an Alto-Shaam dangerous?

The switch has already cut the heat. Should smoke or a burning odor appear, shut the oven down and leave its cabinet closed.

---

**[Read on the site: Alto-Shaam E109: the high-limit safety switch has opened](https://commercialappliancerepair.center/error-codes/alto-shaam-e109/)**

**[Book a visit with CommercialApplianceRepair.center](https://commercialappliancerepair.center/schedule/)**
