Honeywell T6812A1000 Digital Thermostat Installation Guide
CAUTION: ELECTRICAL HAZARD. Can cause electrical shock or equipment damage.
Disconnect power before removing cover.
Terminal Designations
| Terminal | Description |
L | Live |
Ch/Cc | Heating close / Cooling close |
W/Y | Heating open / Cooling open |
N | Neutral |
GI | Low fan speed |
Gm | Medium fan speed |
Gh | High fan speed |
Wiring
- Typical wiring for ON / OFF control in 2 pipe systems (VC4 valves)
- Typical wiring for ON / OFF control in 2 pipe systems (VC6 valves)
Thermostat Installation
Installer Parameters Table
| No | Parameter | Setting |
| 1 | System type | 0 = 2 pipe system, heat only |
| 1 = 2 pipe system, cool only | ||
| 2 = 2 pipe system, heat or cool, manual changeover (default) | ||
| 9 | Temperature Scale | 0 = °F |
| 1 = °C (default) | ||
| 13 | Cycles Per Hour value for HEATING | 1 – 12 (default = 4) |
| 14 | Cycles Per Hour value for COOLING | 1 – 6 (default = 3) |
| 18 | Temperature display offset | -2.0°C to +2.0°C increment 0.5°C / -4°F to +4°F increment 1.0°F (default = 0°) |
| 19 | Temperature display mode | 0 = Display room temperature (default) |
| 1 = Display setpoint | ||
| 20 | Heating range stops | 10 – 32°C (default maximum = 32°C) / 50 – 90°F (default maximum = 90°F) |
| 21 | Cooling range stops | 10 – 32ºC (default minimum = 10ºC) / 50 – 90ºF (default minimum = 50ºF) |
| 22 | Keypad lockout | 0 = All keys available (default) |
| 1 = All keys locked |
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