WMR-100: erratic exterior temperature - affected by humidity

The exterior temperature in my WMR-100 was showing excessively high temperatures at night when the humidity was high. The unit was 2 years old. I took apart the head and coated the glass bead sensor with epoxy and sprayed shellac over the circuit board. All is fine now. The shellac is a Testor’s spray can, use to seal enamel paints, the kind used in plastic model making hobbies. I do not know which solved the problem, preventing humidity from affecting the reading, but it could have been a crack in the glass sensor.

Hope this helps some.

www.watchobs.com

Hi,
I am having the same problem at the moment, over night the temp climbed to 50c. We had fog and high humidity, so expect water/moisture may be a problem. I have tried to take the unit apart but was unable to get the fins off my WMR100 unit.

I managed to get the 6 little screws off and the top part but was unable to get any furhter. Any pointers?

Would it be worth tying to get an external temp sensor and using this instead???

Any ideas?
Steven.

Sorry, I’m very late in replying to this - the fins needs some coaxing - if I recall, they have a small spring tab that needs to be lifted.

Hi Steven,

Did you ever resolve your issues with erratic temperature? I have exactly the same issue, and the original WTGR-800 sensor unit for the WMR-100 is not available as a spare part in Australia. I’ve pulled apart my sensor, but cannot see any physical damage to the thermistor.

Cheers
Rod

To remove the two ‘fins’ from the sensor pack, you need to remove two ‘slide’ clips, that slip in vertically behind the fins. The clips press against pins inside the fins and prevent the fins rotating out of their locating slots. You will see two small rectangular tabs, attached to the tops of the clips. Push these away from the fins, vertically upward, quite sharply. They were a tight fit on mine, but did submit eventually. You can then rotate the fins slightly out of their slots, and slide them upwards and off the sensor pack barrel.

Keith

quote
coated the glass bead sensor with epoxy and sprayed shellac over the circuit board
unquote

By epoxy do you mean a two part GRP pack?

I bought a WMR100 after whatever the earlier model was called failed when the wind cups (I can’t spell anemometer [anenomes are a pleasant flower] ) blew away in a gust. This replacement model is awful, the control wheel is a very weak, inaccurate and sloppy way of selecting data. Now we have 21.9 degs C with 88% RH. Daft. Thanks for the tipsin this thread…further helpwould be appreciated.

Thanks/out.

Just started to have this strange experience - external temperature reading about 10C high compared with other local stations. Have changed batteries, reset etc. Need to investigate inside the external unit I think. Anyone else had this calibration error?

Is it midsummer, or midwinter where you are?

I have a wmr928 and the external temp reads 3-4 degrees high but doesn’t seem to be humidity dependant. No real idea what causes this but when the snow stops I may take it apart again, last time it made no difference.

I’ve had a WMR100 for over two years and it worked flawlessly. Suddenly, one day after a cold rainstorm, the temperature spiked and stayed erroneously high by 20 degrees. Resetting by itself did not fix the problem. After reading posts on this thread I decided to try dismantling the WMR100, cleaning it, and sealing with “Testors” as others have suggested. It appears to have worked. Thanks for all the tips, especially the one about the tabs that need to be pushed upwards to release the fins.

Warning: lots of spiders and other stuff to clean out in my case. Best to do this outdoors. Then bring it in to dry completely. I assisted with a hair dryer. Then coated all the circuit boards with “Silicone Conforming Coating” (the Fry’s generic equivalent of Testors) and let it air dry overnight. Temperature and humidity readings are now correct and have been working for 2 days through a rainstorm. Will post again if this fix doesn’t hold. Better than purchasing a new weather station!

I am also experiencing the same problem with my WMR100 which I have had for nearly 3 years. The outside temperature one day just started to rise to about 10 deg higher than the actual temp.

I have re set the base but has made no difference I have yet to look at the tower which is on the house roof. The weather here in England is cold and damp at the moment so I may put off going onto the roof until the weather improves as it’s quite slippy up their.

I have been reading the other posts about using Shallac or Testors to seal the circuit bored etc I have also read that silicone was used. Would this be the type which you can buy in tubes like mastic??

Adz.

Hello,

This post is pretty old and I

Very old indeed… Eventually I threw out the MWR-100 and bought the fabulous Davis Vantage pro, even after 10 years and more, it still works as it did when new. Can’t say the same for the WMR which had to be thrown out after three years - the plastics had degraded and were flaking away. Sure, the Davis is 3x the price, but it has already outlived the WMR over 3x, so it’s money in the bank from now on.