Delta Mobrey 772 Series Temperature Switch

Delta Mobrey 772 Series Temperature SwitchPressure Temperature Switch has a flexible thermal system and is suitable for setpoints between -50°C and 150°C with maximum working temperatures up to 250°C.

Designed in the mid-1970s and developed over subsequent years, the Performance Series switch range offers users the broadest range of options, the highest levels of set-point repeatability and the confidence of long term performance that a mature product such as this can prove.

The model 77 Performance Series Vapour Pressure Temperature Switches comprise an armoured capillary attached to the sensing bulb via a semi-rigid extension on which a compression gland slides to enable various depths of thermowell (pocket) to be accomodated. This sensor is coupled to the microswitch via a precision stainless steel mechanism, the combination of which helps deliver the market leading performance customers can expect from the Series.

Delta Mobrey 772 Series Features:

  • Precision stainless steel mechanism for arduous atmospheres and high humidity.
  • Set point adjustable over whole range against calibrated scale with tamperproof adjuster.
  • Weatherproof and Flameproof models ATEX and IECEx
  • Hermetically sealed microswitch option
  • Models for fixed switching differential, adjustable differential and HI-LO operation.
  • Ranges available up to 230 to 300°C (450 to 580°F).
  • Maximum working temperature up to 310°C (600°F).


The 772 Performance Series is suitable for a wide range of applications in:

  • Oil & Gas
  • Chemical
  • Petrochemical
  • Refining
  • Power
  • Food Industry

The choice of models available ensures that the 772 Performance Series is suitable for use in:

  • Corrosive atmospheres
  • Resistant to chemical attack

Delta Mobrey 772 Series Specification:


  • Set point repeatability ± 0.5% of span at 20°C / 68°F ambient.
  • Scale accuracy ± 2% of full scale.
  • For models 721-3, 781 scale accuracy will be effected by relative position of head and sensing bulb i.e., sensing bulb 1 metre above/below head = set point shift ± 1% of full scale approx.

Storage Temperature: -25 to +60°C / -13 to +140°F

Ambient Temperature:

  • -25 to +60°C / -13 to +140°F
  • Models 771-4. A 10°C (18°F) rise in ambient temperature will on average result in a 1°C (1.8°F) fall in set point. On models 721-3, 781 it is advisable to avoid the condition where the ambient temperature is within ± 5°C (± 9°F) of the set point. Under this condition the liquid/vapour phase becomes less well defined and the switching differential increases. Where this condition is unavoidable refer to Models 740/760 Liquid Expansion Temperature Switches or 771-4.

Maximum Working Pressure: System sensing probes for both the capillary and rigid stem version are designed to withstand 100 bar (1500psi) without thermowell.

Enclosure classification: IP66 / NEMA 4X / Flameproof Ex d

Switch output:

  • SPDT or DPDT snap action microswitch (standard)
  • Hermetically sealed (optional)

Process Connection: 3/8 NPT External Sliding Gland, ½ NPT External Direct mounting.

Approximate Weight:

  • Enclosures: “W & N” 2.5kg / 5.5lb (models 731-4 2.2kg/4.8lb); “A & O”
  • 3.5kg /7.7lb (models 731-4 3.2kg/7.0lb); “H” 4.0kg/8.8lb; “K” 8.7kg/19.1lb

Download Data Sheet: Temperature Switch 772


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