Author Topic: Just installed an A/C fan into my VP2!  (Read 3524 times)

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Offline ValentineWeather

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Re: Just installed an A/C fan into my VP2!
« Reply #25 on: June 19, 2017, 01:05:50 PM »
Dendrite mentioned that he uses a fan that pulls around 47 CFM. I would wonder if he ever had issues with his humidity reading too low.

Ask him, CW may be unique but my test have shown much less airflow is needed. 
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Offline ValentineWeather

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Re: Just installed an A/C fan into my VP2!
« Reply #26 on: June 19, 2017, 01:08:36 PM »
Remember a rating of fan is designed for same size chamber anything larger changes what fan outputs. 
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Offline dendrite

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Re: Just installed an A/C fan into my VP2!
« Reply #27 on: June 19, 2017, 04:31:31 PM »
Dendrite mentioned that he uses a fan that pulls around 47 CFM. I would wonder if he ever had issues with his humidity reading too low.
no issues. I tend to run more humid than the local ASOS. Here's my MADIS page.

http://weather.gladstonefamily.net/site/C7324

Offline WxLover16

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Re: Just installed an A/C fan into my VP2!
« Reply #28 on: June 19, 2017, 05:55:33 PM »
Dendrite mentioned that he uses a fan that pulls around 47 CFM. I would wonder if he ever had issues with his humidity reading too low.
no issues. I tend to run more humid than the local ASOS. Here's my MADIS page.

http://weather.gladstonefamily.net/site/C7324

So do I. My closest ASOS always seems to read a few degrees too low for some reason.
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Offline ValentineWeather

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Re: Just installed an A/C fan into my VP2!
« Reply #29 on: June 19, 2017, 06:33:03 PM »
Not sure how the ASOS gets humidity now. It use to use the mirror by chilling down until dew formed on mirror. Lots more accurate I would think if calibrated correctly, that's a big if however because I've seen fog you could cut with a knife and ASOS DP reported low 90's. 
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Offline dendrite

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Re: Just installed an A/C fan into my VP2!
« Reply #30 on: June 19, 2017, 06:45:20 PM »
Not sure how the ASOS gets humidity now. It use to use the mirror by chilling down until dew formed on mirror. Lots more accurate I would think if calibrated correctly, that's a big if however because I've seen fog you could cut with a knife and ASOS DP reported low 90's.
https://en.m.wikipedia.org/wiki/Automated_airport_weather_station

It's now the Vaisala DTS-1

Offline dendrite

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Re: Just installed an A/C fan into my VP2!
« Reply #31 on: June 19, 2017, 06:48:08 PM »
I'll throw in this paper on the DTS-1 too...

https://ams.confex.com/ams/pdfpapers/53362.pdf

Offline ValentineWeather

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Re: Just installed an A/C fan into my VP2!
« Reply #32 on: June 19, 2017, 06:52:18 PM »
Not sure how the ASOS gets humidity now. It use to use the mirror by chilling down until dew formed on mirror. Lots more accurate I would think if calibrated correctly, that's a big if however because I've seen fog you could cut with a knife and ASOS DP reported low 90's.
https://en.m.wikipedia.org/wiki/Automated_airport_weather_station

It's now the Vaisala DTS-1

Thanks for that. It reads for others quote:
Due to problems with the chilled mirror sensor, NWS ASOS sites now use Vaisala's DTS1 sensor, which measures humidity only via capacitance. The sensor is based on a solid state capacitive relative humidity element that incorporates a small heater so that the sensing element is always above the ambient temperature, eliminating the formation of dew or frost. The sensor reports directly in dew point through a calculation based on measured relative humidity and the measured temperature of the heated capacitive element.
Randy, the Aviator is my father in 1963 with his Indian bike

Offline CW2274

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Re: Just installed an A/C fan into my VP2!
« Reply #33 on: June 22, 2017, 02:30:03 PM »
I've been offline for a while, so obviously haven't replied, but thanks to those with the kind words.
As far as questions about the fan WxLover and I use, it is rated for 70,000 hrs (about 8 years) of continuous use in temps well above even what I get, and mine has been in perfect continual use for two years.  As far as drying out the sensor, truly couldn't say, but the 31 does drop quickly when it gets to about 3-4%, (as I've stated in another thread) compared to the ASOS's around me, but I've found that acceptable considering it absolutely rocks above that. Even <3% is not too common here, so I can live with it, especially when compared to my SHT11 and 15. The 67 CFM is not too much IMHO (I think my obs prove that), as long as the fan is NOT sealed in, but it absolutely need not that much power to be effective. I chose this fan not just for it's performance in my heat, but the red LED located on the ISS that tells me the fan is getting power 24/7, so I'll know if the GFI has tripped. Very convenient! The ONLY downside is more cleaning of the sensor and chamber. I'll take it!
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Offline dcriner

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Re: Just installed an A/C fan into my VP2!
« Reply #34 on: June 23, 2017, 06:27:32 PM »
How did you mount it? Is the fan good for outdoor locations?
Doug

Offline SpartanWX

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Re: Just installed an A/C fan into my VP2!
« Reply #35 on: June 24, 2017, 10:58:22 PM »
Really everyone the shield itself is very efficient and only needs so much air flow to work properly. These shields are as good as RM Young but going with to much airflow can cause problems. I've tried to get CW to reduce airflow. If going with a outside AC or DC fan go with the minimum airflow type fan.
Too much can make sensor erratic and dry out humidity sensor (wear out sensor) prematurely.

I'm okay with a outside fan, I was one of the originators if not the first to use electric fan back in 90's but don't go overboard. The Davis aspirated shield works very well with just the solar powered DC fan, going much higher brings up issues.

Are you of the opinion that the 67 CFMs that my fan pulls (just like CW2274's) is too much?
Too much?  Pshaw!  I too was concerned with the reliability and underperformance of the piddly little fan in a stock FARS setup. So I'm now I'm running duplex alternating 240V, 2HP squirrel cage blowers on a custom built stainless steel plenum. Of course I've got the whole shebang tied in to my standby generator. At 500 CFS apiece we are talking serious responsiveness!

Overkill? Maybe. But the fine variations in temperature changes I can monitor with this setup make it all worth it. If a gnat farts within so much as 10' of the intake I'm gonna know about it!

Offline dendrite

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Re: Just installed an A/C fan into my VP2!
« Reply #36 on: June 25, 2017, 11:50:38 AM »
Really everyone the shield itself is very efficient and only needs so much air flow to work properly. These shields are as good as RM Young but going with to much airflow can cause problems. I've tried to get CW to reduce airflow. If going with a outside AC or DC fan go with the minimum airflow type fan.
Too much can make sensor erratic and dry out humidity sensor (wear out sensor) prematurely.

I'm okay with a outside fan, I was one of the originators if not the first to use electric fan back in 90's but don't go overboard. The Davis aspirated shield works very well with just the solar powered DC fan, going much higher brings up issues.

Are you of the opinion that the 67 CFMs that my fan pulls (just like CW2274's) is too much?
Too much?  Pshaw!  I too was concerned with the reliability and underperformance of the piddly little fan in a stock FARS setup. So I'm now I'm running duplex alternating 240V, 2HP squirrel cage blowers on a custom built stainless steel plenum. Of course I've got the whole shebang tied in to my standby generator. At 500 CFS apiece we are talking serious responsiveness!

Overkill? Maybe. But the fine variations in temperature changes I can monitor with this setup make it all worth it. If a gnat farts within so much as 10' of the intake I'm gonna know about it!
I have a good sarcasm detector, but even I'm not sure on this one. I never put anything past people on here. ;)
« Last Edit: June 25, 2017, 01:12:09 PM by dendrite »

Offline DaleReid

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Re: Just installed an A/C fan into my VP2!
« Reply #37 on: June 25, 2017, 04:05:40 PM »
females never pass gas. 
ECWx.info
&
ECWx.info/t/index.php

Offline WxLover16

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Re: Just installed an A/C fan into my VP2!
« Reply #38 on: June 25, 2017, 04:44:49 PM »
How did you mount it? Is the fan good for outdoor locations?

It was an easy mount. I simply had to shave off around 1/8th" of two bottom sides and it fit right in where the old Davis stock fan sat. It's good for outdoors if you water-proof it enough. Unfortunately, apparently I did not quite go the distance in sealing it well enough and it quit on me a few days ago after a heavy rain so I had to order another one.  :roll: ](*,)
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Offline dupreezd

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Re: Just installed an A/C fan into my VP2!
« Reply #39 on: June 25, 2017, 05:20:20 PM »
Don't ask how I know this  :oops:, but look at the picture.
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Offline CW2274

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Re: Just installed an A/C fan into my VP2!
« Reply #40 on: June 25, 2017, 05:25:05 PM »
How did you mount it? Is the fan good for outdoor locations?
Unfortunately, apparently I did not quite go the distance in sealing it well enough and it quit on me a few days ago after a heavy rain so I had to order another one.  :roll: ](*,)
As I said in a PM to you, since your GFI didn't trip, the connection didn't short, it must have a break in it somewhere. Regardless, neither would cause the fan motor itself to fail. I'm betting it still works just fine unless it burned up from binding, which we also spoke of.
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Offline CW2274

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Re: Just installed an A/C fan into my VP2!
« Reply #41 on: June 25, 2017, 05:26:28 PM »
Don't ask how I know this  :oops:, but look at the picture.
Then his GFI would have tripped.
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Offline dupreezd

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Re: Just installed an A/C fan into my VP2!
« Reply #42 on: June 25, 2017, 05:31:07 PM »
Is that not a 12V fan? GFI will only trip if there is a patch to ground.
I am just pointing out where water could have come in as has happened to me.
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Offline CW2274

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Re: Just installed an A/C fan into my VP2!
« Reply #43 on: June 25, 2017, 05:41:15 PM »
Is that not a 12V fan? GFI will only trip if there is a patch to ground.
I am just pointing out where water could have come in as has happened to me.
It is, but 120V is run out to a transformer hooked to the fan.
Yes, water certainly could get in there, but besides wrecking the fan, would that not trip the GFI?
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Offline dupreezd

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Re: Just installed an A/C fan into my VP2!
« Reply #44 on: June 25, 2017, 05:47:52 PM »
A power supply isolates AC ground (building) from DC ground, especially on switching power supplies such computer supplies.
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Offline CW2274

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Re: Just installed an A/C fan into my VP2!
« Reply #45 on: June 25, 2017, 05:54:17 PM »
A power supply isolates AC ground (building) from DC ground, especially on switching power supplies such computer supplies.
So I guess that means "no". If that's the case, then maybe this is indeed what happened causing the failure because I've been  ](*,) trying to help him figure out why it quit.
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Offline dupreezd

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Re: Just installed an A/C fan into my VP2!
« Reply #46 on: June 25, 2017, 06:02:33 PM »
In this picture you can see the separation.
You are right, the GFI will not trip if anything goes wrong on the DC side such as letting the smoke out the components.  :-)

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« Last Edit: June 25, 2017, 06:17:46 PM by dupreezd »
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Offline CW2274

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Re: Just installed an A/C fan into my VP2!
« Reply #47 on: June 25, 2017, 06:15:31 PM »
In this picture you can see the separation.
You are right, the GFI will not trip if anything goes wrong on the DC side such as letting the smoke out the components.  :-)

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Thank you for the clarification. Hopefully this will solve his problem cause I'm out of ideas.  :?
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Offline ValentineWeather

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Re: Just installed an A/C fan into my VP2!
« Reply #48 on: June 25, 2017, 06:30:49 PM »
If you want to skip the DC conversion I use AC model: https://www.coolerguys.com/products/mechatronics-80-x-25mm-ac-115v-fan-uf80b12-bth  good for very low temps I experience in -30F range.
Randy, the Aviator is my father in 1963 with his Indian bike

Offline dupreezd

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Re: Just installed an A/C fan into my VP2!
« Reply #49 on: June 25, 2017, 06:40:41 PM »
Looks like a pretty good fan. 24cfm at 3100rpm and ONLY 35dB. That is quiet.
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