--- title: "Middleby Marshall IO_COMM_LOST: the CTX touch screen stopped hearing from its I/O board" description: "What IO_COMM_LOST means on Middleby Marshall IO_COMM_LOST: the CTX touch screen stopped hearing from its I/O boards, what to check before booking, and when it…" url: "https://commercialappliancerepair.center/error-codes/middleby-marshall-io-comm-lost/" --- # Middleby Marshall IO_COMM_LOST: the CTX touch screen stopped hearing from its I/O board A CTX oven splits its brain in two: the touch screen you press, and an input/output board that actually drives the infrared panels, fans and conveyor motors. ## What IO_COMM_LOST actually means. A CTX oven splits its brain in two: the touch screen you press, and an input/output board that actually drives the infrared panels, fans and conveyor motors. If those two go 15 seconds without a message, the oven beeps and posts IO_COMM_LOST. The manual adds that this message takes priority over every other one, so any alarm that was active before it will show again once the link is restored. Middleby Marshall commercial appliance display · also shown as IO_COMM_LOST What to do when IO_COMM_LOST 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 Middleby Marshall Middleby Marshall ovens on this site are the kitchen's non-pizza baking and roasting work; pizza service calls belong to our pizza oven site. ### Source Middleby Marshall CTX DZ26T, DZ33T and DZ55T infrared conveyor oven owner's operating and installation manual (Rev G) CTX DZ26T, DZ33T and DZ55T infrared conveyor ovens with the touch screen (manual Rev G). The message shows only on the Manual Mode and Preset Mode main screens. ## Before you book, in this order. Each step comes from Middleby Marshall's own guidance for IO_COMM_LOST on its commercial appliances. Follow it to the end: the last card says whether this is a visit. 01 Touch the screen to acknowledge the message and watch whether the oven carries on normally. 02 Should it come back, switch the oven off, give it sixty seconds and turn it on again so both boards boot together. 03 Note any other message that shows up after the link returns, because the oven was hiding it while IO_COMM_LOST was active. 04 If IO_COMM_LOST keeps returning, book a visit; a loose harness, a failing I/O board or a power supply problem are technician checks. ### 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 IO_COMM_LOST does not say the infrared panels have failed, only that the screen cannot confirm what they are doing. It is different from MC1_COMM_LOST and MC2_COMM_LOST, which concern the belt motor controls. ## What you may notice with it. The commercial appliance problems IO_COMM_LOST 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 - [**Commercial Convection Oven Baking Unevenly Across the Racks**](https://commercialappliancerepair.center/problems/commercial-oven-uneven-bake/) Problem ### Commercial Appliance Error Code on a Combi, Fryer, Dish Machine or Laundry Display 8 causes, cheapest first Where IO_COMM_LOST 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/) ## Middleby Marshall commercial appliances. Middleby Marshall ovens on this site are the kitchen's non-pizza baking and roasting work; pizza service calls belong to our pizza oven site. [Middleby Marshall commercial appliance repair](https://commercialappliancerepair.center/brands/middleby-marshall/) More Middleby Marshall codes [MC1_COMM_LOST](https://commercialappliancerepair.center/error-codes/middleby-marshall-mc1-comm-lost/) [MC2_COMM_LOST](https://commercialappliancerepair.center/error-codes/middleby-marshall-mc2-comm-lost/) [PROBE_TL_FAULT](https://commercialappliancerepair.center/error-codes/middleby-marshall-probe-tl-error/) [FAN_HIGH_CURRENT](https://commercialappliancerepair.center/error-codes/middleby-marshall-fan-high-current/) [FAN LOW CURRENT](https://commercialappliancerepair.center/error-codes/middleby-marshall-fan-low-current/) [MC1_HIGH_CURRENT](https://commercialappliancerepair.center/error-codes/middleby-marshall-mc1-high-current/) [LIMIT BOARD HIGH TEMP](https://commercialappliancerepair.center/error-codes/middleby-marshall-limit-board-high-temp/) [LIMIT BOARD PROBE FAULT](https://commercialappliancerepair.center/error-codes/middleby-marshall-limit-board-probe-error/) [IO BOARD HIGH TEMP](https://commercialappliancerepair.center/error-codes/middleby-marshall-io-board-high-temp/) [CONTROL COMPARTMENT HIGH TEMP](https://commercialappliancerepair.center/error-codes/middleby-marshall-control-compartment-high-temp/) [HIGH TEMP CHECK FANS](https://commercialappliancerepair.center/error-codes/middleby-marshall-high-temp-check-fans/) [FAN FAULT](https://commercialappliancerepair.center/error-codes/middleby-marshall-fan-error/) [All 14 Middleby Marshall codes](https://commercialappliancerepair.center/error-codes/#codes-middleby-marshall) 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 65 codes of this kind](https://commercialappliancerepair.center/error-codes/#family-board) Middleby Marshall 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 Middleby Marshall's own words > Communication between the User Interface and Input/Output (IO) has been interrupted for 15 seconds. [Middleby Marshall CTX DZ26T, DZ33T and DZ55T infrared conveyor oven owner's operating and installation manual (Rev G)](https://www.middlebymarshall.com/wp-content/uploads/2022/01/CTX-DZ26T-DZ33T-DZ55T-Series-Electric-Oven-Rev-G.pdf) [Middleby Marshall CTX DZ26T, DZ33T and DZ55T infrared conveyor oven owner's operating and installation manual (Rev G)](https://www.middlebymarshall.com/wp-content/uploads/2022/01/CTX-DZ26T-DZ33T-DZ55T-Series-Electric-Oven-Rev-G.pdf) [Middleby Marshall CTX DZ26T, DZ33T and DZ55T infrared conveyor oven owner's operating and installation manual (Rev G)](https://www.middlebymarshall.com/wp-content/uploads/2022/01/CTX-DZ26T-DZ33T-DZ55T-Series-Electric-Oven-Rev-G.pdf) Every code on this site is taken from the manufacturer's documentation, never from a forum or a parts listing. CTX DZ26T, DZ33T and DZ55T infrared conveyor ovens with the touch screen (manual Rev G). The message shows only on the Manual Mode and Preset Mode main screens. ## Middleby Marshall IO_COMM_LOST 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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Touch the screen to acknowledge the message and watch whether the oven carries on normally. If it comes back, it needs a visit. ### Why did other alarms appear on my CTX oven right after IO_COMM_LOST cleared? The manual says the communication message replaces all others while it is active. Anything still wrong comes back into view once the screen and I/O board reconnect. ### Can a CTX oven keep cooking during IO_COMM_LOST? Do not count on it. With the screen unable to reach the I/O board, heat and belt time are no longer being checked, so hold product until the message clears. ### Does IO_COMM_LOST on a CTX mean the touch screen is broken? Not necessarily. The screen, the I/O board, the cable between them or the power feeding them can each cause it, which is why a repeat needs testing on site. --- **[Read on the site: Middleby Marshall IO_COMM_LOST: the CTX touch screen stopped hearing from its I/O board](https://commercialappliancerepair.center/error-codes/middleby-marshall-io-comm-lost/)** **[Book a visit with CommercialApplianceRepair.center](https://commercialappliancerepair.center/schedule/)**