Product Literature

CommStat 3 Product Data Sheet (Rev. 10) - English (pdf - 1452 KB)
CommStat 3 Product Data Sheet (Rev. B) - Spanish (pdf - 293 KB)
CommStat 3 Product Data Sheet (Rev. B) - French (pdf - 360 KB)

CommStat 3™ Lead/Lag Controller commstat3new

A solid state control package designed to operate a fully or partially redundant air conditioning system.

The Marvair CommStat 3™ is factory programmed with industry standard set points to facilitate installation. If desired, each of the set points can be quickly and easily changed in the field by the installer. The lead/lag controller insures equal run time on each air conditioner and allows the lag unit to assist upon demand.

The CommStat 3™ controller can be used with Marvair's ComPac® I and ComPac® II air conditioners or environmental control units. The CommStat 3™ is housed in an aqua blue, corrosion resistant, polycarbonate enclosure.


  • Thermostat Range:
    • Cooling: 72° - 95°F (22° - 35°C)
    • Heating: 50° - 80°F (10° - 27°C)
  • Programmable in °F or °C
  • Two stages of heating and two stages of cooling

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
  • Adjustable on-off differential of each stage
  • Adjustable interstage differential

Ease of Installation
  • Insensitive to phasing of units
  • 24 VAC
  • No additional power source required
  • Built-in temperature sensor with up to three optional remote sensors

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

For detailed specifications, performance, and efficiency information, download the Product Data Sheet from the document list on this page.