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CommStat™ 3 SC Lead/Lag Controller (Patent Pending)

The CommStat 3 SC lead/lag thermostat/controller by Marvair¨ is a solid state thermostat/controller designed to operate two, 2-stage Marvair air conditioners in a fully or partially redundant air conditioning system in a telecommunications shelter. When used in this application, the CommStattm 3 SC controls four steps of cooling. This can provide substantial energy savings compared to a conventional four step thermostat by maximizing the run time of the air conditioners in 1-stage (higher efficiency) stages. In addition, there is better control of the temperature and humidity by matching the cooling requirement in the shelter with the performance of the air conditioners.

Specifications/Features Thermostats

  • Thermostat Range:
  • Cooling: 72° - 95°F (22° - 35°C)
  • Heating: 50° - 80°F (10° - 27°C)
  • Programmable in °F or °C
  • Four stages of cooling and four stages of heating
Differential
  • Insensitive to phasing of units
  • 24 VAC
  • No additional power source required
  • Built-in temperature sensor with up to three optional remote sensors
Ease of Installation
  • Adjustable on-off differential of each stage
  • Adjustable interstage differential
Ease of Operation
  • Easy to change set points
  • Push button to change lead and lag unit
  • LED's indicate
  • Control power
  • Function (heating or cooling)
  • Lead unit
  • High or low refrigerant pressure lockout
  • Digital display of temperature
  • Comfort button temporarily overrides set points for 90 minutes
  • If one A/C loses power, the other A/C automatically advances to the lead position
  • Indefinite program retention if power is lost
Alarm Relays
Dry contacts can be used for remote alarm. Relays can be wired either for Normally Open or Normally Closed
  • Power
  • Low building temperature
  • High building temperature
  • Refrigerant pressure lockout
  • Smoke detector input
  • Smoke detector output

See Product Data Sheet for installation information and detailed operational specifications.

Downloadable literature
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