Tecnologic TLZ 12
4-digit cooling/heating thermostat like the TLZ 11 with added defrost interval and length, defrost display lock and defrost control from the digital input.
What it is: Refrigeration controller with defrost. Same keypad, probe and alarm settings as the TLZ 11, plus timed defrost.
Key combo: Hold P about 5 s for parameters. Hold UP/DEFROST about 5 s for a manual defrost.
Tecnologic TLZ 12 error codes
| Code | Meaning | Likely cause | How to reset |
|---|---|---|---|
| E1 / −E1 | Probe fault | Probe open or shorted, or reading outside the allowed range | OUT follows tonE / toFE. Check wiring and the probe. |
| EEPr | Memory error | Internal memory fault | Check and re-enter the parameters. |
| od | Power-on delay running | od time counting after power-up | Information only. |
| dEF | Defrost running (dLo = Lb) | Timed, manual or input-started defrost | Information only. |
| PdEF | After-defrost period (dLo = Lb) | Display held until the reading comes back within Etdu of the set point | Information only. |
| HI | High temperature alarm | Above SP + HAL | Clears below the threshold less dAL. |
| LO | Low temperature alarm | Below SP − LAL | Clears above the threshold plus dAL. |
| AL | Digital input alarm | Input set as external alarm (diF = 3) active | Clears when the input returns to normal. |
How to enter service / parameter mode
- Hold P for about 5 seconds until the SET LED lights and the first code shows.
- If a password is set (PASS), enter it with up/down and press P.
- Hidden level: switch off, hold P, switch on still holding P, keep holding about 5 s.
Parameter list
| Code | What it does | Range | Default / typical |
|---|---|---|---|
| SPLL | Lowest set point | −58.0 to SPHL | −50.0 |
| SPHL | Highest set point | SPLL to 302.0 | 100.0 |
| SEnS | Probe type | Ptc / ntc | Ptc |
| OFS | Probe offset | −30.0 to 30.0 | 0.0 |
| Unit | Units | °C / °F | °C |
| dP | Decimal point | On / OFF | On |
| FiL | Reading filter | OFF to 20.0 s | 2.0 |
| HSEt | Differential | 0.0 to 30.0 | 2.0 |
| tonE | OUT on time with probe fault | OFF to 99.59 min.s | OFF |
| toFE | OUT off time with probe fault | OFF to 99.59 min.s | OFF |
| Func | Output mode | HEAt / CooL | CooL |
| dint | Defrost interval (OFF = none) | OFF to 24.00 h.min | 6.00 |
| dEFE | Defrost length | 0.01 to 99.59 min.s | 30.00 |
| dCt | Interval counts | rt clock time, ct OUT on time | rt |
| dLo | Display in defrost | OFF live, On frozen reading, Lb dEF / PdEF labels | OFF |
| Etdu | Unlock display within this of SP after defrost | 0.0 to 30.0 | 2.0 |
| PSC | Compressor protection type | 1 delay at switch-on, 2 delay after switch-off, 3 delay between starts | 1 |
| PtC | Compressor protection time | OFF to 99.59 min.s | OFF |
| od | Output delay at power-up | OFF to 99.59 min.s | OFF |
| HAL | High alarm, offset above SP | OFF to 100.0 | OFF |
| LAL | Low alarm, offset below SP | OFF to 100.0 | OFF |
| dAL | Alarm differential | 0.0 to 30.0 | 2.0 |
| ALd | Alarm delay | OFF to 99.59 min.s | OFF |
| PAL | Alarm delay at power-up | OFF to 24.00 h.min | 2.00 |
| dALd | Alarm and display hold after defrost | OFF to 24.00 h.min | 1.00 |
| USrb | U key function | OFF none, 1 on / stand-by | OFF |
| diF | Digital input | 1 start defrost, 2 end defrost, 3 external alarm, 0 none (negative values also listed) | 0 |
| PASS | Parameter password (OFF = none) | OFF to 9999 | OFF |
| SP | Set point | SPLL to SPHL | 0.0 |
How to change and save a setting
- Pick a code with up/down and press P.
- Change it with up/down and press P to store.
- Wait about 20 s, or hold up or down, to exit.
Other useful key presses
| Task | How |
|---|---|
| Manual defrost | Hold UP/DEFROST about 5 s outside programming; DEF LED lights |
| Change set point | Tap P, adjust, tap P or wait 15 s |
Notes
- Temperature alarms stay blocked during defrost and for dALd afterwards.
For licensed technicians only. This equipment can involve mains voltage, high-voltage microwave circuits, gas and refrigerant. Isolate power (and gas) before opening panels, follow the manufacturer's manual and your local licensing rules (for example ARC refrigerant handling and electrical or gas licences). Wrong settings can spoil food or damage equipment. Check every value on the unit in front of you before changing it.
Based on: Tecnologic TLZ 12 operating instructions (ISTR 06416, Vr.01), Tecnologic UK copy. Always check the manual for your exact model and software version.
ServiceModes is not affiliated with Tecnologic or any other manufacturer. Written in our own words from the manufacturer's documentation.