Jackson Glasswasher Error Code F2: Check Booster Thermostat
F2 on a Jackson Delta HT-E-SEER glasswasher means the booster heater is staying on when it should have shut off at set temperature. The manual points to the contactor, the booster temperature input or the booster probe. Turn the machine off and call for service.
High: a heater that will not switch off at set temperature needs a fix before use.
- Code
- F2
- Maker
- Jackson
- Equipment
- Glasswashers
- Applies to
- Delta HT-E-SEER glasswasher dishmachines
What does Jackson error code F2 mean?
A glasswasher's final rinse has to be hot, but it must not overshoot. The control switches the booster heater off once the set temperature is reached, using the booster probe T3 as its reference. If the heater keeps running past that point, it shows "F2 Service needed" with "Check booster thermostat". The manual lists three causes: a booster heater contactor that is not turning off, a failed booster temperature input (P12) on the IO module, or a failed booster probe (T3). Whichever one it is, the effect is the same: the heater has no working off signal. In a busy bar that may show up as rinse water that steams more than usual or a machine that feels hot to the touch. The manual does not say what the glasswasher does while F2 is on screen, so we do not state it, and it gives no temperature figure for the set point.
Affected models and control systems
Jackson Delta HT-E-SEER glasswasher dishmachines. The error table is on printed pp. 25-27 of the Delta HT-E-SEER manual.
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
- Very hot final rinse water
- Steam rising from the glass rack area after a cycle
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 contactor whose contacts have fused after years of cycling
- A probe that reads low because its tip has scaled over
- A probe lead pulled loose while the machine was moved for bar cleaning
Safe checks before calling for service
- Turn the glasswasher off at its switch and let it cool before opening the door.
- Do not put your hands into the rinse spray area while it is hot.
- Restart later and see whether F2 returns.
- Tell the technician how hot the rinse felt compared with normal.
How a technician diagnoses error code F2
- Confirm F2 and check the actual rinse temperature with a thermometer.
- Check the booster heater contactor for welded contacts.
- Verify the IO module output turns off above set temperature.
- Substitute a 1.2 kOhm resistor for T3 and verify the booster heater turns off; otherwise replace the IO module.
- Verify T3 resistance against the manual's table and replace T3 if it is wrong.
- A booster heater that does not switch off can overheat the water, and the tests are done on live parts.
- Separating a bad probe from a bad IO input needs the manual's resistor method and a meter.
- Hot rinse water can scald, so testing starts with the machine cooled.
How error code F2 differs from similar codes
F2 is the booster heater that stays on. F5 is the opposite on the same circuit, and F7 is the wash tank version of F2.
Technical reference
- Document
- Delta HT-E-SEER Installation, Operation, and Service Manual
- Edition
- 07610-004-54-86-E (Rev E)
- Models / control
- Delta HT-E-SEER glasswasher dishmachines
- Section
- Fault Codes / Troubleshooting, printed pp. 25-27 (PDF pp. 32-35)
- 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 glasswasher error codes
Is F2 safe to ignore for one shift?
We advise against it. The booster heater is not shutting off at set temperature.
Why does the manual list three causes?
The probe, the IO module input and the contactor are all links in the chain that switches the heater off.
Is the glasswasher F2 the same as the dishmachine F2?
The meaning and causes match. Only the machine and the manual differ.
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.