Topic: 24 Hours FARS Wrong Direction?

[alexstaar]

Hello all! I'm new to the forum, but so far I can tell there's loads of very helpful info on here!

Well to start, I just got my Davis VP2 with 24 Hour FARS for Christmas. I love it so far! My set up is WeatherLink IP through a WiFi bridge to Cumulus. I did this because I wanted my console separate from the computer and router. The ISS and anemometer are on a tripod in my backyard. There's a picture of the station on the "About this PWS" on my Wunderground page here: http://www.wunderground.com/personal-weather-station/dashboard?ID=KALHUNTS54#history.

So now to my problem... I believe my fan is running backwards. It is blowing air out of the bottom of the unit and not sucking in like the diagram in the manual suggests. I think this may be what is causing the little spikes on the temp graph during the day. I'm guessing that the sun is heating up the plates and as air crosses the plates as it's sucked in at the top, it is heated slightly. Has anyone ever had this problem? I saw a thread where someone installed a new board and the fan spun backwards, but not straight out of the box brand new... I emailed Davis, but I don't expect to hear back from them until Monday.

Also, I'm not so sure the fan is spinning at night either. During the day when the sun shines right on the solar panel, it makes an audible whirring and slight knocking noise. When I cover the panel, it abruptly slows down and there's hardly any air blowing out of the bottom. The same is true at night. There is absolutely no noise even with my ear touching the unit and no noticeable air coming out of the bottom. I've taken a piece of plastic wrap to test it out; during the day it easily pushes the plastic away from the vent but at night, nothing.

So I guess my questions are: is there an easy fix to reversing the fan direction? Is it a bad board? Are the batteries installed backwards? Are the batteries loose? Would removing the batteries and charging them help them last longer into the night?

Thanks for the help in advance!

Alex

[Gulfcoast]

We all pay lots of $$$ for a Davis station. I would not wait days for an email reply. I'd call them before the weekend.

[ValentineWeather]

I would call also. Email response is hit and miss plus they most likely need to ask direct questions.

[dalecoy]

Although unlikely, you could certainly check to see if the battery was installed backwards.

The manual tells how to check "the motor", which implies airflow:

To check the motor, listen for the slight whirring or, on a calm day, test air
suction by placing a very thin one-ply piece of plastic the size of the fan
screen at the bottom of the radiation shield. If the fan is working, the plastic
will stick to the fan screen.

So, clearly, if it's blowing air out the bottom, that's not correct.

BTW, many years ago I lived in Huntsville at 321 Forrest Park Ct.

[alexstaar]

Now that I think about it, calling them would be a better solution... But since I only have 30 mins left to call tonight, I'll wait until next week. I'll probably take down the shield tomorrow and check out the batteries (If they are loose, backwards, etc.). Also, I've seen a few pictures and diagrams of the inside of the unit, but I kind of want to see it with my own eyes!

dalecoy, I'm actually a meteorology student at UAH living just off Holmes Ave!

[dalecoy]

Thinking about the situation - if in some way the solar panel was connected "backwards", that might explain all of the symptoms.

[alexstaar]

I thought about that as well... which side should the black and white be respectively soldered? Does anyone know?

[CW2274]

If battery or batteries were installed backwards, without solar help, the fan would not work at all. If the fan is indeed pushing air out the bottom, the only logical reason I see is that the impeller was installed backwards, which is indeed possible. A backwards installed impeller could also cause possible clearance issues causing the knocking noise or inoperation altogether.

[alexstaar]

That's another possibility which is why I want to disassemble and investigate the shield tomorrow just to see if anything looks obviously wrong.

[alexstaar]

Is it possible to easily flip the propeller on the fan once disassembled?

[CW2274]

That's another possibility which is why I want to disassemble and investigate the shield tomorrow just to see if anything looks obviously wrong.

Not to be obvious, but do yourself a favor and remember how the ISS goes back together.

[CW2274]

Is it possible to easily flip the propeller on the fan once disassembled?

Yes, merely a firm grip. Do not bend the shaft!

[alexstaar]

My thinking is that once I can see the fan, I'll check to see if it's actually spinning on only battery power. If yes, I'll attempt to simply flip the fan. If not, I'll try something else! But kind of hoping at this point that it's just a flipped fan!

[MesquiteWx]

Thinking about the situation - if in some way the solar panel was connected "backwards", that might explain all of the symptoms.

I am thinking along these lines as well. In logic since it is a simple DC motor if you reverse the polarity then it would spin the motor the other direction. I have the daytime FARS and it has been awhile since I put mine up. I am not sure if there is only one way it connects to the ISS or not but, could their be a chance it is connected to the ISS backwards? Just throwing out some ideas.

[alexstaar]

So if the batteries are connected the right way, would reversing both of them reverse the fan to the right way or could that damage the board? I'll also check the connection of the board and the solar panel and the board to the fan to see if those connections are flipped.

[dalecoy]

..... If the fan is indeed pushing air out the bottom, the only logical reason I see is that the impeller was installed backwards, which is indeed possible.

It turns out that is technically incorrect (assuming by "impeller" you mean the blade assembly or "propeller").  Putting it on the shaft either way will blow the same way.  [I know that doesn't sound logical] 

If you mean to turn the whole motor-with-fan-blades-attached around, then that would in fact reverse the airflow.

[alexstaar]

..... If the fan is indeed pushing air out the bottom, the only logical reason I see is that the impeller was installed backwards, which is indeed possible.

If you mean to turn the whole motor-with-fan-blades-attached around, then that would in fact reverse the airflow.

I suppose if it's possible to do so, then I would try that.

[CW2274]

..... If the fan is indeed pushing air out the bottom, the only logical reason I see is that the impeller was installed backwards, which is indeed possible.

It turns out that is technically incorrect (assuming by "impeller" you mean the blade assembly or "propeller").  Putting it on the shaft either way will blow the same way.  [I know that doesn't sound logical] 

If you mean to turn the whole motor-with-fan-blades-attached around, then that would in fact reverse the airflow.

Well I'll be damned. I took out my spare fan unit, flipped the blade, blew, and it went the same way. That one escaped me.

[alexstaar]

I suppose we all learn something new every day!   

[alexstaar]

It makes sense though... If you look at a ceiling fan blade and rotate it 180º, it is in the same position as before. Therefore, if spinning the same way, it will move the air the same direction!

[dalecoy]

As I said, it doesn't sound logical. 

But consider a regular screw.  Hold it loosely between your fingers, and rotate it clockwise.  It moves in one direction.  Now, flip it over and turn it in the same clockwise rotation.  It still moves in the same direction.

[CW2274]

I suppose we all learn something new every day!   

Ya, to remember to engage brain before opening mouth.

[dalecoy]

I suppose we all learn something new every day!   

Ya, to remember to engage brain before opening mouth.

I firmly believe that this fact can only be learned in one of the following ways:

1.  Deciding to "fix" a piece of home equipment that way, without witnesses, and finding out it wasn't a "fix".

2.  Making an "apparently logical" statement in public and being corrected.

3.  Observing someone else doing (1) or (2) above.  [Least personally embarrasing]

[alexstaar]

Haha agreed! Well, all aspects of education aside, I'll be sure to report my findings tomorrow afternoon! Perhaps with pictures to show you all to see if anything looks backwards. Thanks for all the help and insight!

[ggsteve]

If battery or batteries were installed backwards, without solar help, the fan would not work at all.

Isn't this the exact symptom that the OP discusses in his original post?  The fan works backwards when the solar panel is functioning, but when covered or at night he detects no movement from the fan.

Oh yeah, welcome to the forum Alex!