Condensation in ventalation.

[CrazyKappa]

Since I am not yet running Co2, I run a direct intake in the winter, (also run a humidifier so I am running VPD) well I live in Maine, it gets quite cold out, well cold air entering an aluminum "heatsink" that sits in a warm room creates a bit of water...

First time I noticed it I was damn lucky I was not electrocuted, had it dripping on a power strip. Well those issues are sorted out, but I still have two, first is the water, I put a towel on the floor under it, but still worried it will ruin the floor overtime.

The other issue is the fan itself, when its really cold its dripping too, one night when it was very cold it sounded like the bearings were freezing up. Its not a very cheap fan, (Can-Fan) but I worry about either starting a fire, or electrocuting myself.

I have a few ideas, but wanted input to see if there is something I overlooked, or if its not as big of a deal I am making it out to be. First is to move the fan further back from the intake, its about 1.5' feet away right now, but i can move it about 6' away from the intake.

The other idea is to buy insulated tubing, that would reduce dripping from the tubing. But would it not increase dripping from the fan, even if further back? The aluminum ducting acts like a heatsink, so longer the heatsink before the fan, the more the heatsink gets to warm up the income air, before it hits the fan.

Any ideas/thoughts?
Thank you very much!

 

[queequeg152]

that's not aluminum ducting. you dont/cant galvanize aluminum. its galvanized sheet steel.

insulate the duct.

the fan should be insulated too. the air inside the duct should be exceptionally dry from a grains per cubic foot of air standpoint... cold air simply cannot hold any appreciable moisture so i doubt moisture is condensing inside your fan unless you are leaking alot of room air into your cold air duct.

if you ARE condensing moisture inside your duct, you need to agresivly air seal the duct itself. go buy some mastic and skrim tape or some 3" FSK butyl adhesive tape.

 

[CrazyKappa]

Was not talking about the inlet being aluminum, but the ducting going from the inlet to the fan. I have not checked if there is moisture in the ducts/fan, I just know the outside is soaked on a cold day. They make 6" insulated flex duct, ill pick some up, not too much i can really do about the inlet, how would i go about insulating the fan? Build a box, mount fan in box, fill with fiberglass insulation? Or would I be better with the foam board insulation?

Thank you very much!

 

[CrazyKappa]

Again not sure if moisture is getting into fan, but one night it was like 10 below, and I thought I was going to have a blown bearing come morning. But nothing since, been running fine, perhaps it was not moisture it just did not like the cold.

 

[troutman]

A cold trap is what you need.

https://en.wikipedia.org/wiki/Cold_trap

 

[DemonTrich]

I ran I to the same.issue. I even had r8 ducting from point of entry to intake duct. I removed everything and fired up my ac.

 

[queequeg152]

good luck building a cold trap for hundreds of cfm... it would need to be the size of a 55 gallon drum.

would make a hell of a dehumidifier though...

because you have hard ducted inlet, i would reccomend you buy some r-6 or preferably r8 FSK (foil skrim kraft) faced insulation wrap.

you would wrap this insulation around your hard duct, and staple it(outward clinching stapler) or tape it, or mastic it in place.

you would also wrap the flex duct... but your flex is sloppy, so you need to pull it much much tighter and strap it to the walls or ceiling (1.5" duct strapping), or what ever you have to do to get it taught.

runs of flex need to be as linear as possible. this is the mistake all duct installers make... trying to make 90's, 45's etc with the flex.

use 3 or 5 gore( preferred) 90's or 45's to get the inlet duct inline with your fan, or better yet... lower the fan to be inline with the inlet duct.

to diablotrichs point, yes you will probably STILL get condensation on surfaces that receive this cold air.

so say... you insulate properly and fix all the air leaks etc, if you take this cold air and blast it onto a sheet of glass, you will STILL get condensation because this air is STILL COLD, so be careful how you mix this air stream into your warm wet air.

if you let any surface fall below the rooms dew point you WILL get more condensation.

you also must air seal this insulation wrap as best as possible. the fiberglass blanket will resist movement of air, but air sneaking in from your room can still mingle with the colder surfaces against the duct if it is not sealed properly. get some 3" FSK tape w/ butyl( preferred) or acrylic( still good) adhesive tape and wipe the taped seems with a bondo spreader or credit card. alternativly you can use mastic and fiberglass skrim... but this takes some more skill to do properly and can be quite messy.

mastic and skrim is better long term... but im guessing this thing wont be around for years and years.

 

[queequeg152]

Again not sure if moisture is getting into fan, but one night it was like 10 below, and I thought I was going to have a blown bearing come morning. But nothing since, been running fine, perhaps it was not moisture it just did not like the cold.

i dont know anything about the construction of that fan... but its possible that the bearing lubricant is inadequate at lower temps i suppose. thing is... bearings are usually shielded from the airflow, and they rapidly heat up from the friction of the balls rolling around the race.

you might consider adding a wye to your inlet, w/ a damper on both intakes.

when its too cold, you would adjust open the damper facing the room, and mix in more room air and less outside air.

 

[elios]

You have to inclinate it

 

[mojave green]

Passive intake, lung room, low cfm fan for intake are a few solutions.

 

[Hookah79]

I too have that problem.Was bringing and exhausting air from the opposite sides of basement,and condensation was out of control.It was on on the vinyl ducting,y splits ducts,every freaking piping (except the hot water pipe ).

I stopped doing it this way for now,and just let my ac and dehuey do the work.I've still got more insulation to do.My basement is just one room. So when cold air comes in this warm room condensation builds up.

Funny thing is when i had 2 10x10 rooms i had built at first,i had no issues whatsoever.It's when i tore em down and used entire basement that these problems surfaced.

 

[CrazyKappa]

Thank you everyone who contributed, I made some adjustments to the flex duct, and took notes on the supplies needed, soon as this damn storm blows over I will do it up properly.

Thank you!