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Q: 1/2" Disc Thermostats - What is the standard differential (hysteresis or Delta T) for 1/2" Disc Thermostats?
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A : 30°F (17°C)
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Q: 1/2" Disc Thermostats - Are tighter or wider differentials available?
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A : Yes, 15°F to 100°F (8°C to 56°C)
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Q: 1/2" Disc Thermostats - What is the tolerance on opening and reset?
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A : Tolerances are as follows:
50°F to 249°F (10°C to 120°C)
OA Models
Open ±5.4°F (±3°C)
Close ±10.8°F (±6°C)
CA Models
Open ±10.8°F (±6°C)
Close± 7.2°F (±4°C)
250°F to 320°F (121°C to 160°C)
OA Models
Open ±7.2°F (±4°C)
Close ±10.8°F (±6°C)
CA Models
Open ±10.8°F (±6°C)
Close ±7.2°F (±4°C)
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Q: 1/2" Disc Thermostats - Can the thermostat withstand vibration?
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A : Yes, standard test is 2mm amplitude with a vibration frequency of 1,000 C.P.M. (Cycles per Minute) applied in the x, y and z direction for duration of 20 minutes.
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Q: 1/2" Disc Thermostats - Can the thermostats withstand DC voltages?
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A : Yes, tested by manufacturing only the following ratings apply:
12VDC 10 Amps 30,000+ Cycles
24VDC 7.5 Amps 30,000+ Cycles
48VDC 4.5 Amps 30,000+ Cycles
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Q: 1/2" Disc Thermostats - Are the OA and CA thermostats submersible?
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A : No, however Selco has the ability to over mold thermostats so that they are moisture resistant.
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Q: 1/2" Disc Thermostats - How do I know if I need gold contacts?
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A : If your application amperage is .250 Amp (250 mA) or less. Gold contact prevent premature failure due to oxidation of the contacts at low amperage levels. Oxidation forms an insulation layer on the contact and low current does not arc enough to burn off the oxidation.
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Q: 1/2" Disc Thermostats - At what rate of temperature rise will these devices remain accurate?
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A : Devices are tested at 1.8°F (1°C) per Minute, but can see a rate of temeprature rise as fast as 10°F and still remain accurate.
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Q: 1/2" Disc Thermostats - Will the thermostat fail open or closed?
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A : There is a 90% probability that the thermostat will fail open.
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Q: 1/2" Disc Thermostats - What is the Mean Time Between Failure (MTBF)?
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A : On a case study we estimated 132,000 hours of operation.
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Q: Bulb & Capillary - What Capillary length is available?
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A : Standard is 36 inches (915mm)
Customs can range from:
• In Copper: 18 inches to 8 feet (457mm to 2438mm)
• In Stainless Steel - 18 inches to 4.6 feet (457mm to 1420mm)
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Q: Bulb & Capillary - How many inches of capillary should I immerse in the media?
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A : Recommended is 2 inches (50mm)
• If less than or more than 2 inches, may vary from actual calibrated set point
• Manufacturing calibrates at 2 inches immeresed
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Q: Bulb & Capillary - What type of media is used in testing bulb and capillary thermostats?
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A : Water - 194°F (90°C) and lower
• Salt Bath - 196°F to 752°F (91°C to 400°C)
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Q: Bulb & Capillary - What is the rate of temperature rise while testing bulb and capillaries?
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A : 2°F to 3°F (1°C to 1.5°C) per Minute
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Q: Bulb & Capillary - At what rate of heat increase is the bulb and capillary most accurate?
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A : 7°F (4°C) per minute
The faster rate of temperature rise the less accurate the thermostat will be (another term for this would be Thermal Delay or Thermal Lag)
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Q: Bulb & Capillary - What is the differential (hysteresis) available on bulb and capillaries?
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A : Closes is 3°F to 4°F (2°C) on lower temperatures and 16°F (9°C) on high temperatures
Widest - Varies on temperature setting
• 40°F - 104°F (4°C - 40°C) Maximum Differential: 7°F - 9°F (4°C - 5°C)
• 85°F - 195°F (30°C - 90°C) Maximum Differential: 16°F - 21°F (9°C - 12°C)
• 120°F - 572°F (50°C - 300°C) Maximum Differential: 45°F - 54°F (25°C - 30°C)
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Q: Bulb & Capillary - Is the Stainless Steel used on Stainless Steel Bulb and Capillary 304?
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A : Yes, it is 304 Stainless Steel
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Q: Bulb & Capillary - Does the bulb and capillary loose accuracy with longer capillary lengths?
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A : No
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