T-stat Model 200 & 201 Lead/Lag Controllers

Optimize Operation & Reduce Energy Consumption

Low cost and easy replacement for ineffective lead/lag controllers

Add lead/lag HVAC control to sites that currently have separate thermostats

Reduce energy consumption through advanced control sequences

Prevent short cycling of HVAC equipment.

LLC_T-Stat_150966_-1_150966-2

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.

Setpoint Name
Value
Normal mode - Lead cool stage 1 on80
Normal mode - Lead cool stage 2 on82
Normal mode - Lag cool stage 1 on84
Normal mode - Lag cool stage 2 on86
Normal mode - All cooling off75
Normal mode - Lead heating on45
Normal mode - Lag heating on43
Normal mode - All heating off 50
Comfort mode - Lead cool stage 1 on76
Comfort mode - Lead cool stage 2 on
78
Comfort mode - Lag cool stage 1 on80
Comfort mode - Lag cool stage 2 on
82
Comfort mode - All cooling off
71
Comfort mode - Lead heating on
55
Comfort mode - Lag heating on53
Comfort mode - All heating off60
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

Specifications

Model 200 Quest Part number: 150966-3
Model 201 Quest Part number: 150966-4

Outputs: Eight solid state digital outputs designed to switch

24VAC

Alarm Output: 2 normally closed relays for high temp and low temp

Input: Thermistor temperature sensor ±1°F (0.5°C)

Dry Contact to inhibit HVAC operation

Display: LCD backlit 2-line by 16-alphanumeric character display

Keypad: Five-button; directional arrows plus enter button

Mounting: Wall mount directly or standard single gang electrical box

Power: 24VAC

Enclosure: 2-piece thermal molded plastic enclosure. All wiring is done on the mounted base and the controller is pull-off

Ambient Operating Temp: 23° to 131°F (-5° to 55°C), 0-95% RH non-condensing

Size: 5.32”W x 3.5”H x 1”D (135 x 89 x 25 mm)

Weight: 0.5 lb. (227 g)