Senasys manufacturers two different lines of sealed thermal switches, 431 series and 2570 series, which are UL873 approved to be hermetically sealed. Our sealed snap disc thermostats are commonly found in environments where condensation, water, dust or other material may be present.
Senasys performed a series of tests with our sealed thermostat switches by submerging them into fresh water and salt water. Our testing found after almost 2 years under 6 feet of fresh and salt water, all fresh water switches operated as intended with minimal corrosion; and the salt water test showed similar results with more corrosion to our 431 series thermostat. Continue reading below for complete test results.
By performing this test, Senasys sealed thermostat switches have proven to be a great product for hazardous environments where water may be present.
If you have an application where condensation or other fluid may be present, please click here to contact our direct technical support team.
Sealed Thermal Switch Water Test
January 2015
We made eight thermal switches (four 431 series and four 2570 series) to submerge in water. Two 431 snap disc thermostats (small – 1/2″) and two 2570 thermostats (larger – 3/4″) in fresh water and two 431 thermostats and two 2570 thermostats in salt water. All thermostat switches were made with a 100°F open on rise. For the 2570 series epoxy sealed thermostat switches, two were made with aluminum caps 2570WT2 and 2 with stainless caps 2570WT1. For the 431 series epoxy sealed thermostat switches, since the caps are the same (Aluminum), we went with different epoxies. Two have black epoxy 431WT1 and the others have blue 431WT2. All were put in 6′ long x 6” diameter PVC pipes.
Water Resistant Thermal Switch Review
February 2, 2015
Pulled a sample from salt water and tested for continuity, which was good. Also tested dielectric and passed that as well. Pictures were taken for a comparison of possible corrosion and all switches looked good. No noticeable corrosion as you can see below.
Switch samples from the fresh water. No corrosion or deterioration.
Switch samples from the salt water. No corrosion or deterioration. Salt residue present, but not destructive.
March 2, 2015
Pulled all thermostat switches and all passed continuity. Put them on heat plate and all snapped really well. However, one 2570WT2 from the fresh water wouldn’t close. Put it in the freezer and it closed and is now operating fine. Will check it on next test. Ran all through 1.5KVAC dielectric tests and no abnormalities.
Fresh water. Again no change in appearance. 4th switch is back in water and will be tested again. The switch performed well.
Salt water. No difference in appearance from February. Salt residue wipes off. Wiring is still good and the boots are fine.
July 10, 2015
Pulled all switches put them on heat plate and all snapped. No signs of corrosion which is a positive. Passed continuity tests and hotplate tests with strong dial snap. Also passed 1.5KVAC dielectric tests with no abnormalities.
Fresh Water. Cosmetically switches looked the same as in March. Also passed 1.5KVAC dielectric tests with no abnormalities.
Salt Water. Cosmetically very minimal saltwater deposit by appearance but easily wiped off with cloth.
November 12, 2015
Pulled all eight thermostat switches out and tested them on a hotplate. The switches tested very well for open/close with nice loud audible snapping sound and simultaneous dial. There were beginning signs of corrosion; one each of the 431 caps for salt & freshwater. Ran all through 1.5KVAC dielectric tests and no abnormalities.
Fresh Water. Cosmetically there was minor corrosion on the aluminum caps but can be wiped off with rubbing alcohol.
The stainless steel cap didn’t have any noticeable signs of corrosion.
Salt Water. Cosmetically there are signs of corrosion on each of the 431 samples. But wipes off by using rubbing alcohol.
August 11, 2016
All eight switches were pulled out from the water and tested on a hotplate. Six thermostat switches tested very well for open/close with nice loud audible snapping sound and simultaneous dial. There was corrosion all of the 431 caps for salt & freshwater. The fresh water caps cleaned up as seen in the photos below. The two salt water switches however did have some internal water causing a failure.
Fresh Water. Cosmetically there was minor corrosion on the aluminum caps but can be wiped off with rubbing alcohol.
The stainless steel cap didn’t have any noticeable signs of corrosion.
Salt Water corrosion on the 431 causing a failure.
Are the sealed thermal switches water resistant?
After almost 2 years under 6 feet of fresh or salt water, all 4 of the freshwater switches are still operating as intended with some signs of corrosion on the Aluminum caps of both the 431 and the 2570 snap disc thermostats. The Stainless Steel cap of the 2570 looks like new.
The 431 series caps did corrode in the salt water enough to fail, however the 2570’s both still work great with minimal to no corrosion on the stainless steel cap.
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