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Low coolant level detector PRC7925

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Hi, all,

I've just bought a coolant low level detector, as above, which arrived in a blue box! How should this work? Using my multimeter connected to the two terminals I can't detect any difference - continuity or non-continuity - when I raise and lower the float. Am I missing something, or has the "blue box syndrome" struck again?


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I think the sensor should change from a few meg ohms to about 680 ohms, but it will not like switching a relay, even assuming you can get one to react to this sort of change. I used a transistorised relay from Interface Solutions, part IS M 12T, which will sense the change without loading the sensor and will drive an indicator. Cost me about £13 a couple of years ago, and has worked fine since.

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Just for balance, the last prc7925 I bought which was either Beramach or Almakes was a simple reed switch operated by a magnet in the float, it measures open circuit when the float is at the bottom ( no coolant) and zero ohms when the float is at the top (coolant full)

wave a compass near it and you should see the magnet make the needle flicker.


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