Middleby Marshall PROBE_TL_FAULT: the CTX top left zone probe reads open
A CTX oven divides its infrared panels into zones above and below the belt, each with its own temperature probe.
Mon–Sat, 8am–8pm
- Sensors and probes
- Commercial controls and board repair
- Source: Middleby Marshall
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What PROBE_TL_FAULT
actually means.
A CTX oven divides its infrared panels into zones above and below the belt, each with its own temperature probe. The manual labels this message Probe Open: Top Left and says it appears when that zone reports more than 1400°F for over 5 seconds, a reading the control treats as a broken probe circuit. The same table has matching messages for the other three zones.
Middleby Marshall commercial appliance display · also shown as PROBE_TL_FAULT, PROBE_TR_FAULT, PROBE_BL_FAULT, PROBE_BR_FAULT
What to do when PROBE_TL_FAULT shows on the commercial applianceKind 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.
MakeMiddleby 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.
SourceMiddleby 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. The other zones print PROBE_TR_FAULT (top right), PROBE_BL_FAULT (bottom left) and PROBE_BR_FAULT (bottom right) with the same explanation.
Before you book,
in this order.
Each step comes from Middleby Marshall's own guidance for PROBE_TL_FAULT on its commercial appliances. Follow it to the end: the last card says whether this is a visit.
Acknowledge the message and look at the zone temperatures on the screen for one that reads far off the others.
Run a test item and compare how it browns on the top left side with the rest.
Hold product for that lane if the item comes out pale or scorched on one side.
Book a visit if the message comes back; the probe or its wiring behind the panels is a technician repair.
Still there?
It usually turns into commercial controls and board repair. Book with the code and the model number.
What not to do
PROBE_TL_FAULT does not mean the oven is actually at 1400°F; the number is how the control recognizes an open probe. It is also separate from the limit board messages, which watch for real overheating.
What you may
notice with it.
The commercial appliance problems PROBE_TL_FAULT tends to arrive with. Answer these at the commercial appliance before anyone is booked.
All problems
Where PROBE_TL_FAULT usually leads
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 repairMore Middleby Marshall codes
Sensors and probes on other makes
In Middleby Marshall's own words
Probe Open: Top Left
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. The other zones print PROBE_TR_FAULT (top right), PROBE_BL_FAULT (bottom left) and PROBE_BR_FAULT (bottom right) with the same explanation.
Middleby Marshall PROBE_TL_FAULT 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 areasTampa BayFL · 31 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
Questions
about PROBE_TL_FAULT.
Can I clear PROBE_TL_FAULT myself?
What do TL, TR, BL and BR mean in CTX probe messages?
Is my CTX oven really at 1400°F when PROBE_TL_FAULT shows?
Can a CTX keep cooking with one zone probe out?
Back to your everyday
Still showing PROBE_TL_FAULT?
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.