Topic: Wireless ISS SIM cover leaking in strong winds

[hamlet]

Installed a wireless ISS (talking to a VP2 Envoy) 6 months ago (start of summer) and up until yesterday have only had 30mm (1.2") of rain from occasional showers.  Yesterday we had our first winter storm resulting in 21mm in 36 hours.  After a particularly heavy downpour (120mm/hr) the wind speed dropped more than half and then later in the day after another soaking it dropped to zero and stayed there despite the anemometer spinning at a great rate in the wind.

During a break in the weather today I took the cover off the SIM (Sensor Interface Module) and found a lot of water inside even though the foam insert was still firmly located in the cable access port.  It looked like the cover was a little warped so I guess that the cover wasn't sealing properly and the wind was forcing the rain into the SIM box.  Unplugged the wind cable connector and the socket was full of water.  Wiped out as much moisture as I could, replaced the cover and put gaffer tape around the cover joint.  Although the wind speed is no longer stuck on zero it's a lot less than I would expect.  It also goes straight from 0 to 1.6kph (2mph) so I guess there's still some moisture in the socket.

Is this a known problem with these units?

Is there a better solution than gaffer tape?

David

[wxtech]

Is this a known problem with these units?

Is there a better solution than gaffer tape?

David

It's easy to get the cover misaligned.  It feels tight but not sealed. 
Years ago mine wouldn't transmit.  Davis offered replacement, but I decided to dry it out first.  Three days with the SIM in my house and then it worked OK.
If your enclosure is defective, contact Davis for replacment.

[hamlet]

It's easy to get the cover misaligned.  It feels tight but not sealed. 
Years ago mine wouldn't transmit.  Davis offered replacement, but I decided to dry it out first.  Three days with the SIM in my house and then it worked OK.
If your enclosure is defective, contact Davis for replacment.
[/quote]

Thanks for the tip.  As I can reach the ISS with a long power cord I might try drying it with a hair dryer, once the rain has stopped!

[wxtech]

It's easy to get the cover misaligned.  It feels tight but not sealed. 
Years ago mine wouldn't transmit.  Davis offered replacement, but I decided to dry it out first.  Three days with the SIM in my house and then it worked OK.
If your enclosure is defective, contact Davis for replacment.

Thanks for the tip.  As I can reach the ISS with a long power cord I might try drying it with a hair dryer, once the rain has stopped!

Wait until the ground is dry or remove the ISS.  Don't stand in a puddle with a hair dryer.  But you knew that, just be careful.  What is the voltage in Australia?  110/220?

[hamlet]

What is the voltage in Australia?  110/220?
[/quote]
It's 240 VAC; although prior to 1985 in Western Australia it was around 250 VAC, which I recall reading somewhere was due to the state's first power utility getting a batch of transformers with non-standard ratios at rock bottom prices from some mining company in South Africa. 

[wxtech]

What is the voltage in Australia?  110/220?

It's 240 VAC; although prior to 1985 in Western Australia it was around 250 VAC, which I recall reading somewhere was due to the state's first power utility getting a batch of transformers with non-standard ratios at rock bottom prices from some mining company in South Africa.  

Twice the ouch of our 120VAC here in the states.  120 can be lethal but 240, scary.  Two phase 220 is on our air conditioners, electric ranges, big motors, etc.  Dangerous.

[hamlet]

Installed a wireless ISS ...  After a particularly heavy downpour (120mm/hr) the wind speed dropped more than half and then later in the day after another soaking it dropped to zero and stayed there despite the anemometer spinning at a great rate in the wind.

During a break in the weather today I took the cover off the SIM (Sensor Interface Module) and found a lot of water inside even though the foam insert was still firmly located in the cable access port.  It looked like the cover was a little warped so I guess that the cover wasn't sealing properly and the wind was forcing the rain into the SIM box....

I had a closer look at the SIM cover today and realised the what I thought was warping along the bottom edge was actually a slight bowing inwards at the centre designed to engage the cover latch (see attached pic.).

I think the culprit was actually the cable access port.  Although the cables a fairly tightly packed in by the foam insert there are still gaps which would fill with rain and a combination of surface tension and wind would force the water into the bottom of the SIM.

My first attempt at a fix for this is to pack blu-tak around the cables in the access port and then cover this with gaffer tape.  May have to wait a week or two to see if this works as there are no more storms forecast.

[hamlet]

Installed a wireless ISS ...  After a particularly heavy downpour (120mm/hr) the wind speed dropped more than half and then later in the day after another soaking it dropped to zero and stayed there despite the anemometer spinning at a great rate in the wind...  I took the cover off the SIM (Sensor Interface Module) and found a lot of water inside even though the foam insert was still firmly located in the cable access port.  It looked like the cover was a little warped so I guess that the cover wasn't sealing properly and the wind was forcing the rain into the SIM box....

... I think the culprit was actually the cable access port.  ... a fix for this is to pack blu-tak around the cables in the access port and then cover this with gaffer tape...

We've just had another pretty fierce winter storm and the same problem recurred, only this time, as well as the wind going to zero, the rain values started fluctuating wildly, far in excess of the actual rainfall.  Water had got into the RJ connectors of both sensor cables.  So I'm back to thinking it's the SIM cover that's the problem.  After drying out all the sockets and connectors I packed petroleum jelly into the connector joints and then into the perimeter of the cover where it butts against the rubber seal on the SIM housing.

Hopefully that will fix it.

[johnd]

I presume that this was a new VP2 ISS 6 months ago and not a previously used one? The original VP2 stations (early 2005) did have a potentially faulty antenna seal that could allow water ingress on to the SIM board via the antenna - caused quite a few problems. But there's no longer any general problem with water ingress - there are quite a few VP2 stations near the Atlantic coast of the UK where very wet and very windy conditions are common and any general problem would certainly show up here.

[Aardvark]

give davis an email to their support dept.  According to their replacement parts, the foam plug isn't offered.  I do have issues with that opening.

First the plug is a bad idea .. however...
IF you run in the rain, solar, uv, temp, wind and FARS, it gets really crowded an a pain to work with.  When I installed the daytime FARS, the motor  was bad and had to be replaced three times.  It was a royal pain in the rear to pull out and put in the FARS lead with all the other things that go in that small port opening, then push the foam back in... a poor design.

I am sure the foam must degrade in time from the temperature build up on one side and the elements on the other ( the usual plus pollution).

I also have a soil test station and I noted that the thin gasket around the door tends to come out of the grooves and needs to be periodically pushed back in.
Last,  on that particular station, if you are using 4 soil moisture leads (each are 2 strand) and 4 temperature leads , then include at least one leaf wetness sensor lead, it makes a very crowded entry port through the grommet and allows a gap for critters.

On several occasions  I have found bugs in the sensor box.  Now if those critters can get in, so can moisture.  That as well needs to be improved.

Suggestions?

[johnd]

give davis an email to their support dept.  According to their replacement parts, the foam plug isn't offered. 

It's part 7342.066 - it's on the (printed) Weather Replacement Parts list in front of me.

[hamlet]

Thanks for the replies:

johnd - yes it was new when installed and the antenna seal looks pretty tight.

Aardvark - I've left the cable access port packed with blue-tak and covered with tape so it should be OK.

I'll see how it goes in the next storm.