The Quest T-stat Model 200 & 201 Lead/Lag Controllers are a smart control system designed to replace conventional lead/lag controllers that do not offer wide temperature control windows for advanced optimization of HVAC operation.
The T-stat LLC works with most standard HVAC systems whether they have built-in economizers or no economizers to control up to two stages of cooling per HVAC system. The T-stat LLC provides lead/lag operation with automatic switching based upon time interval and a comfort/occupied mode to change the temperature setpoints for a defined time period.
The compact controller includes separate alarm output contacts for high and low temperature alarms and an input to inhibit HVAC operation. The inhibit function can be used to coordinate with separate stand-alone airside economizer systems. The system has a built-in 2 line by 16-character display for status monitoring of the current temperature and operating mode of the HVAC equipment. All setpoints are factory preset per the customer’s requirements and are not field changeable.
Model 200 & 201 Features
- Controls two HVAC systems for Fan, Cool Stage 1, Cool Stage 2 and Heat.
- Powered from both HVAC’s 24VAC transformers.
- Automatic lead change based on time.
- LCD display for current operating mode and shelter temperature readings.
- Comfort mode to allow “Occupied” temperature settings for defined time period.
- High & Low temp alarm contacts.
- Five button keypad for navigation to other status screens.
- Built-in zone temperature.
- The Model 200 setpoints are factory set to customer’s specifications and are not field changeable.
- The Model 201 setpoints are factory set to customer’s specifications and are field changeable via password.
Setpoints
The Model 200 setpoints are factory set.
The Model 201 setpoints are field changeable via password.
| Normal mode - Lead cool stage 1 on | 80 |
| Normal mode - Lead cool stage 2 on | 82 |
| Normal mode - Lag cool stage 1 on | 84 |
| Normal mode - Lag cool stage 2 on | 86 |
| Normal mode - All cooling off | 75 |
| Normal mode - Lead heating on | 45 |
| Normal mode - Lag heating on | 43 |
| Normal mode - All heating off | 50 |
| Comfort mode - Lead cool stage 1 on | 76 |
| Comfort mode - Lead cool stage 2 on | 78 |
| Comfort mode - Lag cool stage 1 on | 80 |
| Comfort mode - Lag cool stage 2 on | 82 |
| Comfort mode - All cooling off | 71 |
| Comfort mode - Lead heating on | 55 |
| Comfort mode - Lag heating on | 53 |
| Comfort mode - All heating off | 60 |
| Lead Switch time | 24 Hours |
| Comfort mode time | 1 Hour |
| Lead unit fan operation | Automatic |
| High Temp Alarm | 88 |
| Low Temp Alarm | 40 |
Applications
- Utilities/Telecommunication/Cable & Broadband – Remote Cabinets & Shelters
- Data / Switching / Computer Centers / COs / Headends & Hubs
