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Home > Categories > Temperature & Pressure Pete's Plug > 310 Series P & T Plugs and Accessories

Temperature & Pressure Plugs and Accessories, Sizes: 1/4" TO 1/2", 310 Series

  • Quickly take a temperature or pressure reading
  • Self closing Neoprene or Nordel valves after probe removed
  • Cap to protect and additional seal
  • 1/8”, ¼”. & ½” NPT pipe connections
  • For 1/16” & 1/8” probes
  • Brass or Stainless-Steel housing

Neoprene Valve resists waxes, fats, oils, greases, petroleum products, and most refrigerants.
Nordel Valve is an ethylene-propylene based synthetic rubber for hot and cold water, low steam, detergents, phosphate esters, ketone, alcohols, and glycols.
This information is a general guide and product should be tested for applicability under actual conditions.

How to Operate:

These plugs are permanently installed in the line at recommended test points. The cap protects the valve and provides an additional seal. After the cap has been removed, either a test thermometer or a gauge adapter with the proper pressure gauge can be inserted through the two, self-closing valves in the plug. Readings are made, adjustments or test can be accomplished and when the probes are withdrawn, the two valves close. The protective cap is then reinstalled. Tests should be made as quickly as possible since the valve reseal time is dependent upon time of insertion, time, and pressure. Slower valve reseal time can be expected at lower temperature and lower pressures.


  • Available in 1/4" and 1/2" NPT sizes
  • Available in long length
  • Brass body material for non-corrosive service
  • Pressure limits to 1000 psi depending on application
  • Neoprene core (red cap) for temperature range of 0-200°F, for use with natural gas and petroleum products
  • Nordel core (blue cap) for temperature range of 0-275°F, for use with hot and chilled water systems
  • Valve core is self-sealing with pressure cup for superior sealing protection
  • Tested by an independent lab indicates no leaks at high or low pressure

Pete's Plug Instructions
Pete's Plug Chemical Compatability

310 Series Pressure and Temperature Plugs
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Cap retaining straps are standard on all brass plugs.

Pressure Gauge Probe Adapters

The pressure gauge adapter has a probe constructed of 304 stainless steel. The probe is 1/8" in diameter and extends 2" (1 1/2" exposed probe) on the 312-500 adapter and 3 1/2" (3" exposed probe) on the 312-500-XL adapter. The 1/8" diameter probe operates in either the 1/4" or 1/2" Plug. The 312-500-XL Pressure Gauge Probe Adapter will operate in any of the Plugs. Browse pressure gauge plug accessories below.

Pressure Gauge Probe Adapters
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Temperature Gauges

The analog thermometers are constructed of stainless steel, has a 1 3/4" dial and accuracy within 1/2% over the entire scale. Recalibrations is by turning the hex nut on the back of the dial case with stem immersed in a known temperature bath. Digital thermometers have the same specifications as above but can not be recalibrated in the field.

Pressure Gauges

The 3 1/2" pressure gauge plug has an ASME B accuracy of 3/2/3% (2% in middle of scale). It has an adjustable red altitude pointer with a psi and feet of water scale.

Bi-Metal Pocket Testing Thermometers, 5” Stem, 0.156” (4mm)
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Compound Pressure Gauges
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Pressure and Temperature Test Kits
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