# Sinclair UNI Split 2 Service Manual — Exhaustive Control Logic Analysis

Source: `sinclair-sm-uni-split-2-asc-asf-asd-asge-xxbi-bi3-en.pdf` (224 pages, Ver.01, 2022-01-13)
Covers: ASC (cassette), ASF (floor-ceiling), ASD (duct), ASGE (outdoor) — BI2 and BI2-3 series.
Refrigerant: R32. All IDU: 220-240V ~50/60Hz. ODU: single-phase or 3-phase depending on model.

This is a Gree OEM product (Sinclair = rebranded Gree). The control logic, PCB, and protocol
are identical to equivalent Gree commercial uni-split units.

---

## 1. COMPLETE ERROR/FAULT CODE TABLE (107 codes)

### IDU-side errors (displayed on wired controller and/or light board)

| # | Code | Error | Notes |
|---|------|-------|-------|
| 18 | C0 | Wired controller and indoor unit communication failure | |
| 19 | C1 | Indoor ambient temperature sensor error | AD sampling, 5s continuous out-of-range |
| 20 | C2 | Evaporator temperature sensor error | AD sampling, 5s continuous out-of-range |
| 21 | C3 | Condenser temperature sensor error | |
| 22 | C4 | ODU jumper cap error | |
| 24 | C6 | Discharge temperature sensor error | Also: temp unchanged after 10min compressor run |
| 25 | C7 | Condenser meso-temperature sensor error | |
| 26 | C8 | Compressor dial code or jumper cap abnormal | |
| 27 | C9 | Compressor driver memory chip failure | |
| 28 | CE | Wired controller temperature sensor error | AD sampling, 5s out-of-range |
| 29 | CJ | IDU jumper cap error | Jumper cap missing/wrong model |
| 30 | CL | Auto cleaning | Not a fault — status display |
| 31 | CP | Multi-main wired controller failure | |
| 35 | dH | Wired controller circuit board abnormal | |
| 37 | E0 | Indoor fan error | Fan rotation too slow / stopped / protection signal |
| 39 | E2 | Indoor anti-freeze protection | Evaporator pipe temp too low |
| 44 | E9 | Water-full protection | Float switch activated |
| 45 | EE | Memory chip reading and writing failure | |
| 46 | EL | Emergency stop (fire alarm) | Function expansion panel fire alarm terminal |
| 56 | L4 | Wired controller power supply circuit poor | |
| 57 | L5 | Wired controller power supply overcurrent protection | |
| 58 | L6 | One-control-multi: indoor quantity inconsistent | |
| 59 | L7 | One-control-multi: indoor series inconsistent | |
| 64 | LP | IDU and ODU unmatched | |
| 80 | q0 | DC indoor fan driver bus low-voltage protection | |
| 81 | q1 | DC indoor fan driver bus high-voltage protection | |
| 82 | q2 | DC indoor fan AC current protection | |
| 83 | q3 | DC indoor fan driver IPM module protection | |
| 84 | q4 | DC indoor fan driver PFC protection | |
| 85 | q5 | DC indoor fan startup failure | |
| 86 | q6 | DC indoor fan phase-loss protection | |
| 87 | q7 | DC indoor fan driver reset protection | |
| 88 | q8 | DC indoor fan over-current protection | |
| 89 | q9 | DC indoor fan power protection | |
| 90 | qA | DC indoor fan driver current detection circuit error | |
| 91 | qb | DC indoor fan out-of-step protection | |
| 92 | qC | Master control and DC indoor fan driver communication error | 30s comm timeout |
| 93 | qd | DC indoor fan driver module high temperature protection | |
| 94 | qE | DC indoor fan driver module temperature sensor error | |
| 95 | qF | DC indoor fan driver memory chip error | |
| 96 | qH | DC indoor fan driver charge loop error | |
| 97 | ql | DC indoor fan driver input AC voltage error protection | |
| 98 | qo | DC indoor fan driver electrical box temperature sensor error | |
| 99 | qp | DC indoor fan driver AC input zero-crossing protection | |

### ODU-side errors (displayed on ODU mainboard + relayed to IDU)

| # | Code | Error | Notes |
|---|------|-------|-------|
| 1 | A1 | Outdoor fan IPM module protection | |
| 2 | A6 | Master control and DC outdoor fan driver communication error | |
| 3 | AB | DC outdoor fan driver module high temperature protection | |
| 4 | A9 | DC outdoor fan driver module temperature sensor error | |
| 5 | AA | DC outdoor fan AC current protection | |
| 6 | Ab | DC outdoor fan driver reset protection | |
| 7 | Ac | Outdoor fan startup failure | |
| 8 | Ad | Outdoor fan phase-loss protection | |
| 9 | AE | Outdoor fan current detection circuit error | |
| 10 | AF | DC outdoor fan driver PFC protection | |
| 11 | AH | DC outdoor fan driver bus high-voltage protection | |
| 12 | AJ | Outdoor fan out-of-step protection | |
| 13 | AL | DC outdoor fan driver bus low-voltage protection | |
| 14 | An | DC outdoor fan driver memory chip error | |
| 15 | AP | DC outdoor fan driver input AC voltage error protection | |
| 16 | Ar | DC outdoor fan driver electrical box temperature sensor error | |
| 17 | AU | DC outdoor fan driver charge loop error | |
| 38 | E1 | Compressor high pressure protection | High pressure switch open. 1st occurrence: auto-restore on reclose. 2nd in time period: manual reset required. |
| 40 | E3 | Refrigerant lack protection / compressor low pressure protection | Low pressure switch open. Auto-restore on reclose within minutes. Multiple occurrences: manual reset. |
| 41 | E4 | Compressor discharge high-temperature protection | Discharge temp > 115°C |
| 42 | E6 | ODU and IDU communication error | **180 seconds** continuous no-communication triggers this |
| 43 | E7 | Mode conflict | |
| 47 | F3 | Outdoor ambient temperature sensor error | AD sampling, 5s continuous out-of-range |
| 48 | Fo | Recycling refrigerant mode | Status display, not fault |
| 49 | H1 | Ordinary defrosting state | Status display, not fault |
| 50 | H4 | Overload protection | Tube temp > protection value |
| 51 | H5 | IPM module current protection | IPM FO pin low level |
| 52 | H7 | Compressor out-of-step protection | |
| 53 | HC | PFC overcurrent protection | PFC FO pin low level |
| 54 | HE | Compressor demagnetize protection | |
| 55 | L3 | Outdoor fan 1 error | |
| 60 | LA | Outdoor fan 2 error | |
| 61 | Le | Compressor startup failure | |
| 62 | LE | Compressor stalling | |
| 63 | LF | Power protection / Compressor overspeed | |
| 65 | oE | ODU error (see ODU mainboard indicator for specifics) | |
| 66 | P0 | Driver reset protection | |
| 67 | P5 | Compressor phase over-current protection | |
| 68 | P6 | Master control and driver communication error | |
| 69 | P7 | Module temperature sensor circuit failure | |
| 70 | PB | Driver module temperature protection | |
| 71 | P9 | AC contactor protection | |
| 72 | PA | ODU AC current protection | Input current > set protection value |
| 73 | Pd | Sensor connect error (current sensor not on U or V phase) | |
| 74 | PE | Temperature drift protection | |
| 75 | PF | Driveboard ambient temperature sensor error | |
| 76 | PH | Bus high-voltage protection | Busbar voltage > threshold |
| 77 | PL | Bus low-voltage protection | Busbar voltage < threshold while running |
| 78 | pp | Input AC voltage error | |
| 79 | PU | Capacitor charging failure | |
| 100 | U1 | Compressor phase current circuit detection error | |
| 101 | U2 | Compressor phase-loss and anti-phase protection | |
| 102 | U3 | DC bus voltage drop error | |
| 103 | U5 | Overall current detection failure | |
| 104 | U7 | 4-way valve switch-over error | |
| 105 | U8 | Zero-crossing protection | |
| 106 | UL | Outdoor fan overcurrent protection | |
| 107 | Uo | Outdoor ambient temperature abnormal (high temp in heat / low temp in cool) | |

### DRED codes (demand response)

| # | Code | Meaning |
|---|------|---------|
| 31 | d1 | DRED model 1 |
| 32 | d2 | DRED model 2 |
| 33 | d3 | DRED model 3 |
| 34 | dc | Compressor suction temperature sensor error |
| 36 | dJ | AC sequence protection (phase loss or anti-phase) |

### Error reporting mechanism

- Multiple simultaneous errors: displayed in rotation on the wired controller LCD temperature zone
- Historical fault query: last 5 faults stored separately for IDU (parameter C05) and ODU (parameter n6)
- Accessed via: FUNCTION(5s) → C00 → MODE×3 → FUNCTION(5s) → navigate to C05 or n6

---

## 2. CONTROL FLOW STATE MACHINES

### 2.1 Cooling Mode State Machine

```
Power On
  │
  ▼
Cooling start control
  │
  ▼
Indoor fan run  ◄──────────────────────────────────────┐
  │                                                     │
  ▼                                                     │
Satisfying open comp. condition? ──N──► (loop back)     │
  │Y                                                    │
  ▼                                    ┌──────────────┐ │
Comp. and outdoor fan run              │ Comp. stop    │ │
  │                                    │ for 3 min     │ │
  │                                    └──────┬────────┘ │
  │                          N                │          │
  ├──► Oil return IN condition? ──┐    ┌──────┘          │
  │         │Y                   │    │                  │
  │    Oil return operation      │    ▼                  │
  │         │                    │   Comp. and           │
  │         └────────────────────┤   outdoor fan ──N───► │
  │                              │   run                 │
  ├──► Freeze protection IN? ──┐ │    │                  │
  │         │Y                 │ │    ▼                  │
  │    Defrosting operation    │ └── Temp or             │
  │         │                  │    indoor≤Set temp? ──Y─┘
  │         └──────────────────┘
  │
  ▼
  Temp or indoor≥Set temp? ──Y──► Comp. and outdoor fan stop
                                    │
                                    ▼
                                  Comp. stop for 3 min
                                    │
                                    └──► (back to Indoor fan run)
```

**Key point for protocol**: When temperature target is reached, compressor stops with
**3 minute minimum off-time**. Indoor fan CONTINUES running (Mode 1) or stops after
10s delay (Mode 2) — this is configurable via P09 debug parameter "08".

### 2.2 Heating Mode State Machine

```
Power On
  │
  ▼
Heating start control
  │
  ▼
Satisfying open comp. condition? ──N──────────────────────────┐
  │Y                                                          │
  ▼                                          Y                │
Comp. and outdoor fan run     ◄──── Comp. stop for 3 min ◄───┤
  │                                          ▲                │
  ▼                                          │N               │
Avoid cool wind  ◄─────────── (anti-cold-wind logic)          │
  │                                                           │
  ▼                                                           │
Indoor fan run                                                │
  │                                                           │
  ├──► Oil return IN condition? ──Y──► Oil return operation    │
  │                                                           │
  ├──► Defrost IN condition? ──Y──► Defrosting operation       │
  │                                                           │
  ▼                                                           │
Temp or indoor≥Set temp? ──Y──► Comp. and outdoor fan stop    │
  │N                                    │                     │
  └──► (continue running)              ▼                      │
                                 Indoor fan run for 1 min      │
                                       │                      │
                                       ▼                      │
                                 Comp. and outdoor fan stop ───┘
```

**Critical difference from cooling**: In heating, when temperature target is reached:
1. Compressor + outdoor fan stop
2. Indoor fan runs for **1 additional minute** (residual heat blowing)
3. Then indoor fan stops
4. 3 minute compressor minimum off-time before restart

### 2.3 "Avoid Cool Wind" (Anti-Cold-Wind) Logic

This is the feature mapped to byte[12] bit3 (`0x08`) in the IDU 0x31 frame.

**Sequence in heating mode:**
1. Compressor starts, 4-way valve energized (switches to heating cycle)
2. IDU suppresses indoor fan — **"Avoid cool wind"** state active
3. IDU waits for indoor coil (evaporator in cooling = condenser in heating) to reach a warm threshold
4. Once coil is warm enough, indoor fan starts at the set speed
5. After defrost, the sequence repeats: outdoor fan starts first, then indoor fan resumes previous speed after anti-cold-wind is satisfied

**The manual does NOT specify the exact coil temperature threshold**, only "preset value."
From protocol analysis, the coil threshold appears to be around 30°C for exiting anti-cold-wind
based on byte[11] transitions in the IDU_heat captures.

---

## 3. FAN CONTROL LOGIC — DETAILED

### 3.1 Indoor Fan Speed Levels (Ducted Units)

Fan speeds are labeled S01 through S13 (low to high). The wired controller maps user-facing
speed names to internal speed steps based on the **static pressure selection** (P30 parameter).

#### High External Pressure (ESP) Duct — 12k/18k units (5 selections: P3-P7)

| Static Pressure | Super High | High | Medium | Low |
|-----------------|-----------|------|--------|-----|
| P3 | S09 | S08 | S06 | S04 |
| P4 | S10 | S09 | S07 | S05 |
| P5 (default) | S11 | S10 | S08 | S06 |
| P6 | S12 | S11 | S09 | S07 |
| P7 | S13 | S12 | S10 | S08 |

#### High Static Pressure (ESP) Duct — 24k-60k units (9 selections: P1-P9)

| Static Pressure | Super High | High | Medium | Low |
|-----------------|-----------|------|--------|-----|
| P1 | S05 | S03 | S02 | S01 |
| P2 | S06 | S04 | S03 | S02 |
| P3 | S07 | S05 | S04 | S03 |
| P4 | S08 | S06 | S05 | S04 |
| P5 (default) | S09 | S07 | S06 | S05 |
| P6 | S10 | S08 | S07 | S06 |
| P7 | S11 | S09 | S08 | S07 |
| P8 | S12 | S10 | S09 | S08 |
| P9 | S13 | S11 | S10 | S09 |

#### ESP Values per Model (Pa)

| Selection | 12k | 18k | 24k | 30k | 36k | 42k | 48k | 60k |
|-----------|-----|-----|-----|-----|-----|-----|-----|-----|
| P1 | — | — | 0 | 0 | 0 | 0 | 0 | 0 |
| P2 | — | — | 10 | 10 | 10 | 10 | 10 | 10 |
| P3 | 0 | 0 | 15 | 15 | 15 | 25 | 25 | 25 |
| P4 | 15 | 15 | 20 | 20 | 25 | 37 | 37 | 37 |
| P5 | 25 | 25 | 25 | 37 | 37 | 50 | 50 | 50 |
| P6 | 50 | 50 | 50 | 50 | 50 | 75 | 75 | 75 |
| P7 | 80 | 80 | 75 | 75 | 75 | 100 | 100 | 100 |
| P8 | — | — | 100 | 100 | 100 | 125 | 150 | 150 |
| P9 | — | — | 160 | 160 | 160 | 160 | 200 | 200 |

**For the ASD-60BI2**: default P5 = 50Pa, maximum P9 = 200Pa.

### 3.2 Auto Fan Logic

The manual does not explicitly describe the auto fan algorithm, but from the state machines:
- In **cooling**: auto fan adjusts based on delta between room temp and set temp
- In **heating**: auto fan is suppressed during anti-cold-wind, then runs at calculated speed
- In **dry mode**: fan runs at low speed with cycling compressor
- In **fan-only**: outdoor unit does not run; indoor fan only

### 3.3 Blowing Residual Heat (Post-Run Fan Behavior) — Debug Parameter "08"

Two modes selectable via P09 debugging menu, parameter code "08":

**Mode 1 (default, LCD=00):**
- **Cooling**: When temp target reached and compressor stops, indoor fan motor does NOT stop (keeps running)
- **Heating**: When temp target reached and compressor stops:
  - Duct type and floor-ceiling: blow residual heat for **60 seconds**, then stop indoor unit
  - Cassette type: always operates at low fan speed, blows residual heat for **60 seconds** on malfunction
  - After residual heat blowing stops, if start-up condition is NOT met within **15 minutes**, indoor unit fan starts running at low fan speed for **60 seconds** again
  - If start-up condition IS met during this process, immediately enters heating mode
  - If still not met, after blowing for 60s, starts timing for 15 minutes — cycles this process

**Mode 2 (LCD=01):**
- **Both cooling and heating**: Indoor fan motor stops with a **10-second delay** after compressor stops

**Protocol relevance**: This explains the 0x31 byte[4] transitions. In Mode 1 heating standby,
the fan periodically runs at low speed every 15 minutes for 60 seconds — this would appear as
byte[4] toggling between standby and low fan.

### 3.4 Outdoor Fan Control

- 15 speed levels (level 1 = lowest, level 15 = highest)
- Speed is varied to achieve:
  - Cooling at low ambient temperature (low outdoor fan = higher condensing pressure)
  - Heating at high ambient temperature (low outdoor fan = lower condensing pressure)
- In **fan-only mode**: outdoor fan does NOT run
- During **high temperature prevention** (heating): outdoor fan slows down when indoor tube temp reaches threshold

---

## 4. TIMER/COUNTER VALUES

### 4.1 Compressor Protection Timers

| Timer | Value | Context |
|-------|-------|---------|
| **Minimum off-time** | **3 minutes** | After compressor stops, cannot restart for 3 min. Visible in both flow diagrams. Also stated: "if you turn off and immediately turn on, compressor will delay running for 3min" |
| **Minimum run-time** | "some time" (unspecified) | "compressor can only be stopped after running for some time" — exact value not given |
| **Pre-start fan delay** | Unspecified | "indoor fan will run for a while before the compressor starts" |

### 4.2 Defrost Timers

| Timer | Value | Context |
|-------|-------|---------|
| **Defrost entry** | Temperature-based | Outdoor tube temp reaches preset value → defrost starts |
| **Defrost exit** | Temperature-based | Outdoor tube temp reaches defrost-stop preset value → defrost ends |
| **Defrost mode** | Two modes selectable | Debug parameter "06": Mode 1 (LCD=00) or Mode 2 (LCD=01) — details not specified |

### 4.3 Oil Return Timer

| Timer | Value | Context |
|-------|-------|---------|
| **Oil return duration** | **~5 minutes** | "Generally, the oil return takes about 5min" |
| **Trigger condition** | Long low-frequency runtime | "If the unit is running at low frequency for a long time" |
| **Action** | Raise compressor freq to preset oil return frequency | |

### 4.4 Communication Timeout

| Timer | Value | Context |
|-------|-------|---------|
| **E6 comm error** | **180 seconds** | "If no communication between ODU and IDU in continuously 180s, this error will be reported" |
| **qC comm error** | **30 seconds** | "communication between master control and driver is cut off for 30s" |

### 4.5 Refrigerant Recovery Timer

| Timer | Value | Context |
|-------|-------|---------|
| **Entry window** | Within **5 minutes** of power-on | Must start cooling mode within 5 min of power connection |
| **Auto-exit** | **10 minutes** | "if the refrigerant recovery mode has been enabled for 10min, system will exit" |
| **Button combo** | 6 presses in **5 seconds** | "+, -, +, -, +, -" in 5s to enter recovery mode |

### 4.6 Filter Cleaning Reminder (Accumulated Operating Time Counter)

This is a **running hours counter** stored in the unit. The cleaning levels map to specific
accumulated operating hours:

| Level | Hours | Level | Hours | Level | Hours |
|-------|-------|-------|-------|-------|-------|
| 10 | 5,500 | 20 | 1,400 | 30 | 100 |
| 11 | 6,000 | 21 | 1,800 | 31 | 200 |
| 12 | 6,500 | 22 | 2,200 | 32 | 300 |
| 13 | 7,000 | 23 | 2,600 | 33 | 400 |
| 14 | 7,500 | 24 | 3,000 | 34 | 500 |
| 15 | 8,000 | 25 | 3,400 | 35 | 600 |
| 16 | 8,500 | 26 | 3,800 | 36 | 700 |
| 17 | 9,000 | 27 | 4,200 | 37 | 800 |
| 18 | 9,500 | 28 | 4,600 | 38 | 900 |
| 19 | 10,000 | 29 | 5,000 | 39 | 1,000 |

**Protocol relevance for byte[11]**: The unit clearly maintains a cumulative running-time counter
(for filter cleaning). This counter could be the source of the slowly-incrementing byte[11] values
observed across captures — though the scale doesn't match hours directly (byte[11] increments
by 1-2 between sessions lasting hours, not hundreds of hours).

### 4.7 Residual Heat / Standby Cycling Timer (Mode 1 Heating)

| Timer | Value | Context |
|-------|-------|---------|
| **Residual heat blow** | **60 seconds** | After heating comp stop, fan runs 60s at low speed |
| **Standby re-check** | **15 minutes** | If restart condition not met, wait 15 min then blow again for 60s |
| **Cooling fan stop (Mode 2)** | **10 seconds** | Fan delay-off after comp stop |

### 4.8 4-Way Valve Timer

| Timer | Value | Context |
|-------|-------|---------|
| **Post-stop hold** | "a while" (unspecified) | After heating stops, 4-way valve stays energized temporarily before de-energizing |
| **Activation delay** | "a while" after heating mode turned on | 4-way valve energized after heating mode runs for some time |

### 4.9 Sensor Error Detection

| Timer | Value | Context |
|-------|-------|---------|
| **AD out-of-range duration** | **5 seconds continuous** | For all temperature sensors: if AD value exceeds limits for 5 continuous seconds, error is reported |
| **Discharge temp stuck check** | **10 minutes** | C6: after compressor starts, if discharge temp unchanged after 10 min, error reported |

---

## 5. TEMPERATURE THRESHOLDS

### 5.1 Explicit Thresholds from Manual

| Threshold | Value | Context |
|-----------|-------|---------|
| **Discharge high-temp protection (E4)** | **115°C** | Compressor discharge pipe temp |
| **High pressure protection (E1)** | **4.6 MPa** system pressure | Troubleshooting checks "is system high pressure higher than 4.6MPa" |
| **Low pressure protection (E3)** | **0.05 MPa** system pressure | "is system low pressure lower than 0.05MPa" |
| **Low-temperature drying** | **12°C** set temp | In dry mode, set temp 16°C → press "-" twice → 12°C |
| **IPM 15V supply minimum** | **13.5V** | Drive board IPM module's 15V supply below 13.5V causes H5 |

### 5.2 Implied Thresholds (from protocol analysis)

| Threshold | Value | Context |
|-----------|-------|---------|
| **Anti-cold-wind release (heating)** | ~**30°C** coil temp | Byte[11] transition at coil=30°C during heat standby |
| **Post-cool dryout done** | ~**17°C** coil temp | Byte[11] transition at coil=17°C during cool standby |
| **Defrost entry** | "preset value" on outdoor tube | Not specified numerically |
| **Defrost exit** | "preset value" on outdoor tube | Not specified numerically |
| **High temperature prevention (heating)** | "certain value" on indoor tube | Not specified numerically |
| **Overload protection (H4)** | "protection value" on tube temp | Not specified numerically |
| **Anti-freeze (E2)** | Evaporator pipe temp "too low" | Not specified numerically |

### 5.3 Temperature Sensor Specifications

Three NTC thermistor types used:

**15 kΩ @ 25°C** — ODU and IDU ambient temperature sensors (RT2)
- Range: -30°C (911.56 kΩ) to 160°C (0.217 kΩ)
- At 25°C: 15.00 kΩ, 1.650V

**20 kΩ @ 25°C** — Pipeline temperature sensors: defroster (RT1), IDU pipe, ODU pipe
- Range: -30°C to 160°C
- At 25°C: 20.00 kΩ, 1.650V
- At 0°C: 65.37 kΩ, 0.773V
- At 17°C: 28.68 kΩ, 1.356V (anti-cold-wind release?)
- At 30°C: 16.10 kΩ, 1.828V

**50 kΩ @ 25°C** — Discharge temperature sensors (RT3)
- Range: -30°C to 150°C
- At 25°C: 49.191 kΩ, 0.558V
- At 115°C (E4 threshold): 0.8799 kΩ, 3.161V

---

## 6. DIP SWITCH / CONFIGURATION / JUMPER CAP

### 6.1 Jumper Caps

The PCB uses **jumper caps** (not DIP switches) for model identification:

- **IDU mainboard**: JUMP connector — identifies IDU model. Wrong/missing = CJ error
- **ODU mainboard**: JUMP1 (master jumper cap) + JUMP2 (drive jumper cap) — identifies ODU model and compressor type. Wrong/missing = C4 or C8 error
- These are physical plug-in components, not software-configurable

### 6.2 PCB Interfaces — IDU (ASD-48BI2, ASD-60BI2 — your ducted unit)

| # | Connector | Function |
|---|-----------|----------|
| 1 | X4 | Reactor |
| 2 | X3 | Reactor |
| 3 | E | Ground wire |
| 4 | X1 | Live wire input |
| 5 | X2 | Neutral wire input |
| 6 | PUMP | Water pump |
| 7 | COM-OUT | ODU communication interface |
| 8 | WIFI | WiFi interface |
| 9 | COM-BMS | MODBUS gateway interface |
| 10 | ROOM | Ambient temperature sensor |
| 11 | TUBE | Evaporator pipe temperature sensor |
| 12 | DOOR-C | Door control |
| 13 | HEALTH | Cold plasma interface |
| 14 | WATER-DTCT | Water level switch |
| 15 | COM3 | Function expansion interface |
| 16 | COM-MANUAL | Wired control communication interface |
| 17 | JUMP | Jumper cap |
| 18 | CN2 | Motor output |
| 19 | CN1 | 310V DC power supply |

**Note**: The ASD-48BI2 and ASD-60BI2 have a **reactor** (inductor) on the DC bus (X3/X4),
indicating these larger ducted units use DC fan motors with a rectified DC power stage.

### 6.3 PCB Interfaces — ODU (ASGE-36BI2 through ASGE-48BI2)

Key interfaces on larger ODU mainboards:
- **T_SENSOR1**: Outdoor tube temperature pack (RT1=20K defrost, RT2=15K ambient, RT3=50K discharge)
- **T_LAC1**: Low temperature cooling temperature sensor
- **T_SUCK1**: Condenser medium pipe temperature sensor
- **HPP1 / LPP1**: High/low pressure switch interfaces (36-60k units only)
- **4WAY**: 4-way valve
- **FA / FA1**: Electronic expansion valves (cooling / heating)
- **EKV1 / EKV2**: Electronic expansion valves (48k+ units have dual EXV)
- **HEAT_TIE_B1**: Chassis electric heating belt
- **HEAT_TIE_C1**: Compressor electric heating belt
- **DRED1**: DRED communication interface
- **CN2**: External drive DC fan
- **JUMP1 / JUMP2**: Master and drive jumper caps

---

## 7. TEST/DIAGNOSTIC MODE PROCEDURES

### 7.1 Forced Operation (Quick Test after Installation)

**Via cassette light board:**
- Short press TEST (<2s): forced COOLING mode
- Long press TEST (>2s): forced HEATING mode

**Via wired controller (all types):**
- Under power-on status (first power-on, no remote signal received yet):
  - Hold "-" for 5s: forced COOLING test mode
  - Hold "+" for 5s: forced HEATING test mode
  - Press any button: exit test mode

**Restriction**: Can only be enabled on first power-on before any remote/button control signal.

### 7.2 Entering Wired Controller Parameter Menu

Standard entry sequence for ALL parameter settings:
1. From ON or OFF: hold FUNCTION for 5s → displays "C00"
2. Press MODE button 3 times quickly (<1s each, first 2 show "invalid operation", 3rd activates)
3. Hold FUNCTION for another 5s → enters parameter setting, displays "P00"
4. Use +/- to navigate to desired parameter code
5. Press MODE to enter parameter value editing (value blinks)
6. Use +/- to change value
7. Press ENTER to save

### 7.3 Debugging Menu (P09)

Navigate to P09 via the parameter menu above, then press MODE to enter debugging state.
Parameters within debugging mode:

| Debug Code | Function | Values |
|------------|----------|--------|
| 00 | Low pressure protection | 00=disabled, 01=enabled |
| 01 | Refrigerant lacking protection | 00=disabled, 01=enabled |
| 03 | Freeze protection error code display | 00=displayed, 01=not displayed |
| 06 | Defrost mode selection | 00=mode 1, 01=mode 2 |
| 07 | Heat pump / cooling only selection | 00=heat pump, 01=cooling only |
| 08 | Blowing residual heating mode | 00=mode 1 (fan continues), 01=mode 2 (fan stops after 10s) |
| 10 | One-to-more function | 00=invalid, 01=valid |

### 7.4 Inquiry of Ambient Temperature

Hold ENTER for 5 seconds (ON or OFF) → displays indoor temperature for 5 seconds.

### 7.5 Historical Malfunction Query

Via parameter menu → C05 (IDU faults) or n6 (ODU faults) → view last 5 faults.

---

## 8. WIRED CONTROLLER PARAMETERS (COMPLETE)

All accessible via the FUNCTION(5s) → C00 → MODE×3 → FUNCTION(5s) entry sequence:

| Parameter | Function | Values | Default |
|-----------|----------|--------|---------|
| P09 | Debugging menu | (enters sub-menu) | — |
| P13 | Master/slave wired controller | 01=master, 02=slave | 01 |
| P14 | Group control IDU quantity | 02/03/04 | — |
| P15 | Memory function (power resume) | 00=off after power loss, 01=resume state | 01 |
| P16 | Fahrenheit/Celsius | 00=Celsius, 01=Fahrenheit | 00 |
| P20 | Ambient temperature sensor source | 01=air return sensor, 02=wired controller sensor, 03=return in cool/dry/fan, wired ctrl in heat | 01 |
| P22 | Heating temp sensor compensation | -15 to +15 | 0 |
| P30 | Indoor fan motor mode (ESP) | 01-09 (high static), 03-07 (high external) | 05 |
| P42 | Indoor unit address (BMS/centralized) | 1-36 (centralized ctrl) or 1-255 (MODBUS) | — |
| C05 | Historical IDU malfunction query | (read-only, last 5 faults) | — |
| n6 | Historical ODU malfunction query | (read-only, last 5 faults) | — |

### 8.1 Modbus Interface

- Interface: COM_BMS connector on IDU PCB
- Requires gateway: SMG-01
- Baud rate: 9600 bps
- Standard: RS-485
- Address range: 1-255 (for MODBUS)
- Protocol: available from Sinclair upon request

---

## 9. INTERNAL IDU PROTECTION LOGIC (INDEPENDENT OF ODU)

### 9.1 Anti-Freeze Protection (E2)

- **Trigger**: Evaporator pipe temperature too low (exact threshold not given)
- **Action**: IDU reports E2, system stops
- **IDU-autonomous**: Yes — IDU monitors its own coil sensor

### 9.2 Water-Full Protection (E9)

- **Trigger**: Float switch in water tray activated
- **Action**: IDU stops, reports E9
- **IDU-autonomous**: Yes — IDU monitors float switch directly

### 9.3 Indoor Fan Protection (E0)

- **Trigger**: Fan rotation too slow, stopped, or protection signal received
- **Action**: IDU reports E0
- **IDU-autonomous**: Yes
- **Note**: Loose/oxidized short-circuit wire can cause false E0 reports

### 9.4 Anti-Cold-Wind (Heating Mode)

- **Trigger**: Heating mode active, coil not yet warm
- **Action**: IDU suppresses indoor fan independently until coil reaches threshold
- **IDU-autonomous**: Yes — this is purely IDU-side logic. The ODU does not control this.
- **Protocol**: Byte[12] bit3 = 0x08 when active

### 9.5 Residual Heat Blowing (Heating Mode)

- **Trigger**: Compressor stops in heating (temp reached or fault)
- **Action**: IDU continues fan at low speed for 60s (Mode 1) or stops after 10s (Mode 2)
- **15-minute cycling**: In Mode 1, if compressor doesn't restart within 15 min, IDU autonomously runs fan for another 60s cycle
- **IDU-autonomous**: Yes — this cycling is IDU-local logic

### 9.6 High Temperature Prevention

- **Trigger**: Indoor tube temperature reaches threshold in heating mode
- **Action**: IDU signals ODU to slow outdoor fan
- **Partially IDU-autonomous**: IDU detects the condition, ODU acts

### 9.7 Overload Protection (H4 — Cooling/Dehumidification)

- **Trigger**: Motor overload or overcurrent detected
- **Action**: System protection
- **IDU-autonomous**: Yes for motor-related overload detection

### 9.8 Temperature Sensor Error Detection

- All IDU sensors (C1, C2, CE): IDU monitors AD values independently
- 5-second continuous out-of-range → error reported
- IDU-autonomous: Yes

---

## 10. PROTOCOL IMPLICATIONS SUMMARY

### What this confirms for the C-line serial protocol:

1. **Compressor 3-min off-time**: The 3-minute minimum off timer is fundamental. Byte[3] mode
   transitions should always show a >=3min gap between compressor stop and restart.

2. **Anti-cold-wind is IDU-local**: The IDU decides when to release the fan in heating based on
   its own coil sensor — the ODU doesn't tell it when to start the fan.

3. **Residual heat 60s / 15min cycling is IDU-local**: The periodic low-fan operation in heating
   standby is purely IDU logic. This explains periodic byte[4] fan-level changes during standby.

4. **E6 timeout = 180 seconds**: If communication drops for 3 full minutes, E6 is flagged.

5. **Byte[11] and running-time counters**: The IDU maintains cumulative operating time (for
   filter reminders). Some internal counter state could leak into the protocol frame.

6. **The fan speed encoding (S01-S13)** maps to the P30 static pressure parameter. The IDU
   translates user fan speed (Low/Med/High/SuperHigh) to internal step numbers based on its
   installed ESP configuration. This is IDU-local — the IDU does NOT send the raw S-level to
   the ODU; it sends a simplified fan level.

7. **Defrost is ODU-initiated** but causes IDU behavior changes: during defrost, IDU stops its
   fan and re-enters anti-cold-wind on defrost exit.

8. **Oil return raises compressor frequency** for ~5 minutes. This would be visible as a sudden
   frequency increase in ODU frames during steady-state operation.

9. **4-way valve timing**: After heating stops, the 4-way valve stays energized temporarily to
   prevent incorrect switching. The protocol may show a lag between mode change and valve state.

10. **Jumper caps identify the unit model** to the mainboard firmware. CJ/C4/C8 errors mean the
    firmware can't determine what it's controlling — this is how the same PCB handles different
    tonnage units with different fan/compressor configurations.