Is a very low humidity reading an indication of a problem

[Dave Walker]

Over the past 2-3 weeks the rel humidity reading from my fine offset station (as shown on both the unit console and on Cumulus, which is set to calculate the dew point itself) has varied in the range 30 - 80%. It's now 1430 and is at 26%. Earlier this morning at about 0600 cumulus detected a jump from 33 to 70% (which it logged as erroneous). Temp is 13.1, dew point -6.0 Indoor humidity is 57%

I've tried a reset of both console and the sender but it still shows 26%. Could this be a true value or is it unreasonably low and indicative of a fault. I don't know what a 'normal' range would be.

Dave

[AllyCat]

Hi Dave,

That sounds rather low for Somerset at the moment, and a sudden jump of 37% certainly suggests a problem.

Firstly, does the Console LCD confirm the current Cumulus value? Secondly, is your transmitter/sender reasonably accessible?

Just "breathing" over the sender for a few seconds should raise the humidity reading. But better, bring the transmitter indoors beside the Console for an hour or so and see if the internal and external readings agree (within a few percent).

Cheers, Alan.

[beteljuice]

Presumeably like the rest of the UK you've had some rain in the past week ?
If your RH hasn't reached late 90's = problem.

As a general rule of thumb, the outside RH is substantially greater than internal RH.

[Dave Walker]

Thanks for the responses.

Alan, tried your suggestion and brought the transmitter indoors for an hour. Still showed RH of 25% whilst the indoor RH was 57% so I have to assume the transmitter unit has a fault.
Still under warranty (just ) so rang Maplin and replacement unit being sent.

Dave

Just to round this post off - New transmitter received and RH readings now correct, so old one definitely had some issue with RH although everything else was reading sensible values.