Full Gauge MT-512Ri / MT-512Ri plus
Single-relay cooling controller with timed off-cycle defrost (the compressor simply stops), min/max log and key lock.
What it is: Refrigeration temperature controller. MT-512RiL / MT-512RiL plus are the 12/24 V versions. The plus adds an RS-485 port for Sitrad.
Key combo: Hold ▲ and ▼ together 2 s for the F menu (F01 asks for the access code). Hold ▼ 4 s for manual defrost.
Full Gauge MT-512Ri / MT-512Ri plus error codes
| Display | Meaning |
|---|---|
| Err | Probe disconnected or reading out of range |
| OFF | Control switched off (works as a thermometer only) |
| dEF On / dEF OFF | Defrost or cooling started by hand |
| LOC On / LOC OFF | Keypad locked / unlocked |
| Hot | Shown when F08 is set to its minimum: unit works in heating mode |
| rst | Min/max log cleared |
| dEL / rEF / dEF | Status view: start-up delay / cooling / defrost (press ▲) |
How to enter service / parameter mode
- Set point: hold SET 2 s until SEt shows, adjust with ▲/▼, press SET to store.
- Parameters: hold ▲ and ▼ together 2 s until Fun, then F01 shows. Press SET and enter the access code from the manual.
- Pick a function with ▲/▼, tap SET to see it, change it, tap SET to store.
- Hold SET until --- shows to leave.
- °C/°F: enter F01 with the separate unit code from the manual, then choose the unit (settings return to factory values).
- Unlock a locked keypad: power up while holding ▲ for 10 s until LOC OFF shows.
Parameter list
| Code | What it does | Range | Default / typical |
|---|---|---|---|
| F02 | Display offset | -5.0 to 5.0 °C | 0 |
| F03 / F04 | Lowest / highest set point the user may choose | -50 to 200 °C (plus: to 75 °C) | -50 / 75 °C |
| F05 | Differential | 0.1–20.0 °C | 1.0 |
| F06 | Compressor restart delay | 0–999 s | 20 s |
| F07 | Cooling time between defrosts | 1–999 min | 240 min |
| F08 | Defrost time (minimum = heating mode) | 0–999 min | 30 min |
| F09 | Start in cooling (0) or defrost (1) at power-up | 0 / 1 | 0 |
| F10 | Hold the display during defrost | no / yes | no |
| F11 | Delay before control starts at power-up | 0–240 min | 0 |
| F12 | Extra time added to the first cycle | 0–240 min | 0 |
| F13 (Ri) | Compressor with a failed probe: off / on | 0 / 1 | 0 |
| F13 (Ri plus) | RS-485 network address | 1–247 | 1 |
| F14 (Ri) | Probe filter (slows the reading) | 0–9 | 0 |
| F15 (Ri) | Hold time to lock the keys (14 = locking disabled) | 14–60 s | 14 |
| F16 (Ri) | Allow switching control off: never / only when unlocked / always | 0–2 | 0 |
Notes
- F13–F16 differ between the two versions as shown; the plus sheet has no filter, key-lock or control-off settings.
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: Full Gauge MT-512Ri (Ver.11) and MT-512Ri plus instruction sheets. Always check the manual for your exact model and software version.
ServiceModes is not affiliated with Full Gauge or any other manufacturer. Written in our own words from the manufacturer's documentation.
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