Author Topic: Intermittent humidity  (Read 1394 times)

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Offline DaleReid

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Intermittent humidity
« on: January 30, 2016, 10:13:08 PM »
I have a Mark III LR system that has started to give me zero for a humidity reading.

As I understand it, but haven't taken it down from it's perch and operated on it yet, the humidity and temp sensors, while separate devices, are on the same board that sticks up into the little radiation shield.

The temp is always transmitted, and in agreement with the other thermometers I have out there.

A few times a day, for a few minutes to hours (no pattern to any of this) the humidity drops to zero, and it of course goofs up the dew point, etc.

Has anyone encountered this before,and if so, what is the problem you've run in to causing this?

I have a relatively new (1 year old ) battery and the telemetry says all is well with voltages, etc.  The barometer and wind speed and wind direction continue to work just fine, too.

I hope it is something as simple as a bad connection that can be seen and verified, but I know sometimes just playing with the plugs and cleaning up the contacts might help, as may a wee bit of dielectric grease.

I'm just looking for some other users who may have had a problem similar to mine before I venture onto a snow covered and slippery roof to haul the thing down for analysis.  Forewarned is forearmed. 

Thanks for any thoughts.  Dale
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Offline VaJim

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Re: Intermittent humidity
« Reply #1 on: February 01, 2016, 07:42:48 PM »
Hi Dale

What you describe sounds like a failing RH sensor.  I have the non-LR MKIII (similar to yours) and I've replaced the Temp/RH sensor a few times.  Both sensors/calculations are on one small board that drops in under the anemometer.  The trick (as I found out) is making sure you get the replacement down into the shielded area.  Another  concern is lining up the single screw that holds the anemometer in place.

How old is your temp/RH sensor?

I believe the replacement runs about $70 which includes shipping.

Offline DaleReid

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Re: Intermittent humidity
« Reply #2 on: February 01, 2016, 08:45:30 PM »
Jim,
Thanks for the reply.  You confirm what I've been thinking, but didnt know how closely the function of the humidity is to the temperature, as far as the circuitry is concerned.

I think this unit is at least five years old.  I will give RainWise a call to see if the whole sheebang needs to be replaced (easiest?) or the humindity is independent from the temperature unit.

Thanks.

Dale
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Offline VaJim

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Re: Intermittent humidity
« Reply #3 on: February 01, 2016, 09:28:31 PM »
If it's like mine...the temp/rh is all on one small board.  About 3".


Offline DaleReid

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Re: Intermittent humidity
« Reply #4 on: February 01, 2016, 09:47:28 PM »
I assume it is, never had that part of the unit open.  But I've had some previous models to work on and things are reasonably the same.

My thoughts are that it was very well designed to start with and not a lot of slipstreaming or fiddling with stuff was needed.

Thx again, when I get it down I'll try to post a follow up.
Dale
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