Jackson Dishwasher Error Code F2: Check Booster Thermostat
F2 on a Jackson DishStar HT-E means the booster heater is staying on when it should have shut off at set temperature. The cause is in the heater switching or the booster temperature sensing. This needs a technician; switch the machine off if the water is overheating.
High: a heater that will not switch off at set temperature needs a fix before use.
- Code
- F2
- 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 F2 mean?
The booster heater is meant to switch off once the final rinse water reaches its set temperature. The control decides that from the booster probe, T3. When the heater keeps running after it should have stopped, the control shows "F2 Service needed" with the line "Check booster thermostat". The manual lists three causes: the booster heater contactor is not turning off, the booster temperature input (P12) on the IO module has failed, or the booster probe (T3) has failed. Those three sit in a chain. The probe tells the IO module how hot the booster is, the IO module decides when to drop the heater output, and the contactor is the switch that actually cuts power. A break anywhere in the chain gives the same code. The manual does not say what the machine does while F2 is showing, so we only describe what it states: the heater stays on when it should be off, and the operator cannot see which link has failed.
Affected models and control systems
Jackson DishStar HT-E undercounter dishmachines. The F-code table is the same one printed in the DynaTemp door-type manual, pp. 22-24.
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 F2 Service needed, Check booster thermostat
- Rinse water that feels hotter than usual
- Steam from the machine after the cycle ends
Possible causes
Listed in Jackson's documentation
- Booster heater contactor not turning off
- Booster temperature input (P12) on the IO module failed
- Booster probe (T3) failed
Other likely causes — what usually sits behind error code F2 on this control. A technician confirms which one it is before any part is replaced.
- A probe that has aged and now reads colder than the real booster temperature
- A contactor whose contacts have stuck from repeated heavy switching
- A loose probe lead giving a falsely low reading
Safe checks before calling for service
- Switch the machine off at its control and let it rest.
- Note whether the rinse water was unusually hot or the machine ran longer than usual.
- Restart after a few minutes to see whether F2 returns.
- Tell the technician what the final rinse temperature reading was, if the display showed one.
How a technician diagnoses error code F2
- Confirm F2 and check the booster for overheating before touching anything.
- Check the booster heater contactor for welded contacts.
- Verify that the IO module output turns off above set temperature.
- Substitute a 1.2 kOhm resistor for T3 and confirm the booster heater turns off; if not, replace the IO module.
- Verify T3 resistance against the manual's table and replace T3 if it is wrong.
- Checking contactors and IO outputs means working inside a panel with line voltage present.
- A heater that will not switch off can overheat the booster tank, which makes testing time-sensitive.
- Telling a bad probe from a bad IO input takes the resistor substitution method and a meter.
How error code F2 differs from similar codes
F2 is the heater-stays-on code for the booster; F7 is the same condition for the wash tank. F5 is the reverse, a booster that fails to heat.
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
Is F2 dangerous?
The heater is staying on when it should be off, so the water can run hotter than intended. Switch the machine off and call for service.
Can I wash while F2 is showing?
We advise against it, because the heater is not shutting off at set temperature.
What is the difference between F2 and F5?
F2 is a heater that stays on, F5 is a booster that is not heating as expected.
Need help with Jackson error code F2?
A technician confirms the cause on site and gives you the price in writing before any work starts.