home improvement turns into science fair projects?

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JR.
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home improvement turns into science fair projects?

Post by JR. »

After beer oclock I bought a 440 CFM "whisper" blower duct fan to trade hot (dehumidified) air from my back bedroom with cool, air conditioned air from my main room.

I have since determined that 440 CFM is more capacity than I (or anybody would) need. The blower was silly cheap sold as a scratch and dent, without any scratch or dents visible. My suspicion is that a 440 CFM bathroom fan would suck henry homeowner out the vent. :lol:

The ducts don't arrive until mid next week and the blower running unloaded is more like a dull roar than a whisper. I will wait until I get it properly loaded with ducts, but JIC I started thinking about how to slow it down.

A simple folded paper air filter sucked up against the inlet port quiets that end down a bunch. I do not expect the whisper line branding is some big lie so it will quiet down with ducting, but running it slower will be even quieter.

440CFM will suck the air out of my back bedroom completely in about 4-5 minutes... :lol:

The instructions (yes I read those) advise against using solid state controllers (basically light dimmers). I suspect they are worried about mechanical hum being generated by the dimmer period.

Since I try to hug the planet as much as the next guy, a series cap could drop the fan speed without resistive losses, or hum. A quick calculation suggests the blower motor load looks like 24uF... not a cheap film capacitor...

I think I have some 22uF polypropylene caps (only 63V) that I could experiment with..for a half speed test. If they short out the worst case is the fan speeds up again. :lol:

Right now I am putting the cart ahead of the horse since I need to wait for the duct work to determine if I actually have a noise problem.

Always fun around the casa el juan. Life keeps giving me tests.

JR

PS: Still waiting for rain.... Tropical storm barry (oh what a scary name) has dropped less than 1/2" but that about equals the last two weeks of rainfall so all good. I may regret saying this but let it rain. (my apologies to baton Rouge and nawlins who don't need the rain, or the entire MS valley).
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mediatechnology
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Re: home improvement turns into science fair projects?

Post by mediatechnology »

Use a ceiling fan (speed) capacitor.
I don't have any ceiling fans anymore but I recall them being maybe 10 uF?
Scrounge an oil-filled or film cap from a dead microwave oven laying in a trash pile.
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JR.
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Re: home improvement turns into science fair projects?

Post by JR. »

I don't feel lucky but did see one of those bosch high efficiency washing machines on the curb last month for trash pickup day... My much older standard machine keeps on washing (probably bad luck to mention that).

I could buy new 22uf caps for around $6 so two in series or parallel could cover a range of speed possibilities, but this is still all a WAG.

I am getting ahead of myself, let's see how much the duct loading quiets it down. I may be worrying about nothing, while 440CFM is a serious little duct fan.

JR
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Re: home improvement turns into science fair projects?

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I just ordered some experimental run caps for my whisper/blower. I still have no idea of the correct size or if they will even work at all, but that is typical for my life experience. :lol:

As long as I was buying odd parts I ordered some 47uH inductors to swap out in my Franken-lamp version III... The 33uH seems too bright, or brighter then it needs to be, and 33uH+33uH a little dim.

I will report back on my latest experiments/adventures.

JR
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billshurv
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Re: home improvement turns into science fair projects?

Post by billshurv »

don't you have a variac hanging around?

As they are usually around the 50-75W power consumption you must have a transformer somewhere in the shed that would drop down enough to get it quiet. IIRC you can go down about 50% on voltage before it goes non linear for flow.
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Re: home improvement turns into science fair projects?

Post by JR. »

billshurv wrote: Tue Jul 16, 2019 10:17 am don't you have a variac hanging around?

As they are usually around the 50-75W power consumption you must have a transformer somewhere in the shed that would drop down enough to get it quiet. IIRC you can go down about 50% on voltage before it goes non linear for flow.
I actually do (i thought I mentioned that but I have lost a couple posts when the forum software times out and I lose what I wrote.) Life is too short to write some stuff twice. :lol:

Yes I have an old variac that might work... needs to be around 1A. I have that variac in use right now to tweak mains voltage for the programming dongle I use at my computer desk to tweak a wrong voltage wall wart, so would have to replace it with a proper size wall wart.

---

My steel U channel for my slave mower tow bar that was due yesterday is late, but the 8" ducting did show up early and as expected quiets things down a bunch with the ports loaded. The ductwork and end diffuser covers reduce air flow but 440CFM was way too much.

I am optimistic that I may be able to use this almost as is... Caps for possible speed control will probably show up by end of the week. With 2x22uF I can make 11uF, 22uF, or 44uF.

It would be even quieter mounted up in my attic, but not in July in MS... :lol:

JR
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Re: home improvement turns into science fair projects?

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I finished my chores and moved the main blower into the back bedroom where there is already a dehumidifier and air filter making noise.

15' of 8" duct and air inlet cover reach my main room... the noise is very manageable as is.

I need to see how the temps and humidity play out... I hope to cool the back bedroom and dehumidify the main room.

The bedroom dehumidifier has been collecting more water so that part seems to be working.

I need to get this up off the floor, but not a rush.

JR

[edit- its working.. temp in back bedroom dropping, humidity in main room dropping, I love it when a plan comes together. [/edit]
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Re: home improvement turns into science fair projects?

Post by mediatechnology »

My basement is at 84% RH right now and it hasn't rained in 10+ days.
I need a plan.
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Re: home improvement turns into science fair projects?

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mediatechnology wrote: Tue Jul 16, 2019 6:36 pm My basement is at 84% RH right now and it hasn't rained in 10+ days.
I need a plan.
I have been running dehumidifiers 24x7 for years... My Frigidaire is better than my Aeonaire but I am on my second Aeonaire.

[edit] The second Aeonaire was a "free" replacement when the dehumidifier got stupid... I predict a bad internal temperature sensor, since they use temperature as a factor to correct the humidity reading. They did not ask for the broken one's return. So I have spare parts when/if the compressor or whatever wears out [/edit]

Not rocket science or a new problem. The humidity will bite you in other ways if not managed (mold is the obvious one).

JR
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Re: home improvement turns into science fair projects?

Post by JR. »

I just realize that yesterday for the first time in my life I used "duct tape" for its intended purpose . :lol: :lol:

JR

[edit The duct diffuser grilles have flow restrictor inserts giving me even more control over air flow. The 8" duct is spiral expandable that also contracts.

If I restrict the inlet port, and completely open the outlet side, suction inside the inlet pipe, actually causes it to contract and move by itself, unless I weight it down. :lol: [/edit]
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