Jackson Dishwasher Error Code F12: Booster Probe
F12 on a Jackson DishStar HT-E means the booster temperature probe has failed. The manual's single action is to replace the probe that connects to P13. Switch the machine off and arrange service.
High: without a working booster probe the final rinse temperature cannot be controlled.
- Code
- F12
- Maker
- Jackson
- Equipment
- Dish machines
- Applies to
- DishStar HT-E undercounter dishmachines (same F-code table is also printed in the DynaTemp door-type manual 07610-004-29-29-D, pp. 22-24, where F12 is 'Not Used
What does Jackson error code F12 mean?
F12 is the booster-side partner of F11. The booster probe, T3, tells the control how hot the final rinse water is. When the control finds that probe has failed, it shows "F12 Service needed - check booster thermostat". The manual lists one cause, a failed temperature probe (T3), and one action, to replace the probe that connects to P13. The connector number is the useful detail: P13 is where the booster probe plugs into the IO module, so the technician knows which of the two probes is meant without guessing. Note the difference from F2 and F5, which also involve T3 but with other possible causes such as the contactor, the heater and the IO input. F12 covers the probe alone. The manual does not provide a resistance value for it, and it does not describe what the machine does while the code is shown. In the DynaTemp door-type manual the same table lists F12 as Not Used, so this code is specific to the DishStar HT-E.
Affected models and control systems
Jackson DishStar HT-E undercounter dishmachines. The DynaTemp door-type manual 07610-004-29-29-D, pp. 22-24, prints F12 as Not Used.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- Display reads F12 Service needed - check booster thermostat
- Booster temperature shown wrongly or not at all
- Final rinse that does not behave as usual
Possible causes
Listed in Jackson's documentation
- Booster temperature probe (T3) failed
Other likely causes — what usually sits behind error code F12 on this control. A technician confirms which one it is before any part is replaced.
- A probe that has aged in the hot, wet booster area
- A probe lead that has been bent or pinched during cleaning behind the machine
- A connector at P13 with a corroded contact
Safe checks before calling for service
- Turn the machine off, wait a minute, and turn it back on to see whether F12 returns.
- Do not touch the probe or its wiring.
- Check whether the final rinse looks and feels normal.
- Give the technician the exact screen text and the model name.
How a technician diagnoses error code F12
- Confirm F12 and that the probe in question connects to P13.
- Inspect the probe lead and the plug at P13.
- Measure the probe resistance against the manual's table.
- Replace the probe that connects to P13.
- Heat the booster and confirm the temperature reading rises and the code stays clear.
- The probe plugs into the IO module, which is a live control board.
- The booster tank holds hot water, which is a scald hazard when a probe is removed.
- A resistance check against the maker's table is needed to prove the probe is the failed part.
How error code F12 differs from similar codes
F12 is the booster probe; F11 is the wash probe. The same table lists F12 as Not Used in the DynaTemp door-type manual.
Technical reference
- Document
- DishStar HT-E Installation, Operation, and Service Manual
- Edition
- 07610-004-43-79-J (Rev J)
- Models / control
- DishStar HT-E undercounter dishmachines (same F-code table is also printed in the DynaTemp door-type manual 07610-004-29-29-D, pp. 22-24, where F12 is 'Not Used
- Section
- Fault Codes / Troubleshooting, printed pp. 26-28 (PDF pp. 33-35)
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related Jackson dish machine error codes
What is the difference between F12 and F2?
F12 means the booster probe itself failed. F2 means the booster heater is staying on, with the probe as one possible cause.
Is F12 always shown on every Jackson machine?
No. In the DynaTemp door-type manual the same table lists F12 as Not Used.
Can I keep washing?
The control cannot read the booster temperature reliably, so we advise getting the probe replaced first.
Need help with Jackson error code F12?
A technician confirms the cause on site and gives you the price in writing before any work starts.