The Mark 82 is an internally piloted regulator offering better accuracy than a direct acting temperature regulator.  The MK82 is available in two configurations, reverse and direct. The internal pilot valve seats and the main valve seats, in resting position, are up and closed. As the process temperature rises, the fluid in the sensing bulb vaporizes to apply pressure to the pilot diaphragm, opening the pilot valve. The upstream pressure passes through the pilot valve and the pilot port, opening the main valve to provide the required cooling action.
 
The Mark 82FS features a controlled failure option which allows you to predetermine the position of the valve in the event of thermal system failure. It utilizes a vacuum to insure that, if the thermal system fails, the spring pulls down the pilot diaphragm to open the main valve seats on reverse acting valves and close the main valve seats on direct acting valves.

• Sliding gate seats provide straight-through flow for reduced turbulence and quiet operation

• Short stroke for fast response and accurate regulation

• Easily interchangeable CV’s

• Tight shutoff