AC Blower Shop Fan Conversion

[mayday0017]

I recently replaced my whole HVAC system and kept the blower from my 3ton furnace to make into a shop fan. I remember as a kid my gradfather had one and I always loved it on hot days working in the garage (gets kinda warm here in TX). Anyways, I was told I need to block some of the intake and I'm not sure if this is true. I tried searching using "fan" and "Blower" to no real luck. Anyone have pics of their setup to get ideas from. Also can someone explain why the intake needs to be reduced and how to determine the size it should be reduced to?

One other question, I do some painting from time to time, is it safe to use one of these to be an exhaust fan for my thrown together paintbooth?

 

[koditten]

The reason for blocking the intake is to reduce the amount of air that is blown out. If you have no restriction on the squrrel cage, you will have way too much air movement. These fans are designed to move large amounts of air. Just blockthe circular intake with a piece of plywood and you can adjust the fan flow to your preference.

I wish I had some picks I could show you. The one my dad had was suspended by 4 light chains and he fabbed up some sheetmetal to make his intake throttle. Been a lot of years.

You brought this to the front of my mind. I've been meaning to do this for a couple of years now.

It won't be leagal to use one of these fans for your paint booth, but a lot of what we do is illeagal anyways.

If I can smoke a cigar while painting, I aint' gonna worry about an unsealed electrical motor causing a fire. Use your own judgement

Later

KO

 

[mayday0017]

Not sure the point is to throttle it... that's what the 3 way switch is for.... The HVAC guy that was over and saw it sitting on my floor explained it as the motor needs restriction to run properly they are designed to work under a load and with out the restriction there is a problem. Then again I'm just going off what some HVAC guy I don't really know said, which is why i am reaching out on here....

On side note, I'm thinking the same thing as you... I use to smoke cigs and would do it while painting just looking back on it, it might not be my brightest idea...

 

[knobby]

be careful blocking the intake on blowers or fans as some will overheat when operated that way it is better practice to restrict the exhaust side

 

[Hiball]

I have a couple of these in my shop, I just wish they would follow me around when i move.

 

[benny42]

Block the intake on the side without the motor. If you have an amp meter, adjust the intake opening to the nameplate amp draw of the motor or it WILL over-amp and burn
out. They are great fans for shops, no switches or brushes to spark if you paint.

 

[mayday0017]

Block the intake on the side without the motor. If you have an amp meter, adjust the intake opening to the nameplate amp draw of the motor or it WILL over-amp and burn
out. They are great fans for shops, no switches or brushes to spark if you paint.

Thx Benny, that is what I was thinking was right and exactly the information I was looking for!

Anyone have any pics of their setup?

 

[waltinbatonrouge]

Yup. the motor will overspeed and overheat (trip the thermal breaker) without the sufficient load on it...

block the OUTPUT side, air also cools the motor...its easier and will get you the same result
Just put a flat piece of AC sheetmetal over the rectangular output..use the ammeter, slide the sheet metal up until the ammeter reads the rated current draw..usually abit less than 1/2 way blocked....

oh, it will move air but, because it was desgned for max cfm in a small package, the air is very directional and it is loud in a shop. large fan seems to work better

walt

 

[mayday0017]

Yup. the motor will overspeed and overheat (trip the thermal breaker) without the sufficient load on it...

block the OUTPUT side, air also cools the motor...its easier and will get you the same result
Just put a flat piece of AC sheetmetal over the rectangular output..use the ammeter, slide the sheet metal up until the ammeter reads the rated current draw..usually abit less than 1/2 way blocked....

oh, it will move air but, because it was desgned for max cfm in a small package, the air is very directional and it is loud in a shop. large fan seems to work better

walt

Great information, good point on the "directional air" part... I do remember this from the one of my grandfathers I used many years ago. This one will most likely be used when doing paint work to clear all of the fumes out of the air, it should be amazing for that! It will also work good when I want to steal some AC from the house I can just stick it inside the door to the garage for 10 min before I go out to work and should be much cooler in there

 

[waltinbatonrouge]

sneakin' some cool air? NOW you're talkin'

walt