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Instromet wet bulb issues - Resolved

Posted: Sun Aug 19, 2018 7:10 am
by Chapel
Not really C1 or MX related however it took me a while to realise what the issue with my Instromet wet bulb readings was.

The system uses an air sensor and wet bulb sensor within a Stevenson type stacked case with a water bottle suspended underneath. The wick of the wet bulb side has a clear plastic sleeve and if pushed up too high it covers not only the wick but also the thermocouple so preventing evaporation and accordingly giving temperature readings virtually the same as the air sensor. The height of the clear plastic sleeve is not really clear when casually inspected so it is worth taking a very close look or sticking your fingers through a gap and feeling for the top of the tube. The thermocouple is around 30,0mm long so make sure the tube ends below this or you will get issues.

Embarrassingly obvious when you look closely.