Electric Brewing Vent fan - HUGE leak - any help ?

Good morning HBT

I was hoping one of you fine geniuses might be able to help me this morning.

I finally did my first brew in my new Basement Brewery, this weekend.
I know you are shocked to hear I brew in the basement…

I have an Electric Kettle – 10 gallon Kettle – making 7 gal batches. ( another shock – Electric !!)

Blichmann Boil Coil – 10 gal – 240 V = 3750 watts at 100% power
I am about 65% for a rolling boil = 2437 watts - I am only boiling 7 gallons

And I have a 4 inch 190 CFM vent fan pulling off Steam – all the steam went up into the vent fan.
I have a 30 QT SS mixing bowl as a vent hood – got the idea from this thread
https://www.homebrewtalk.com/showthread.php?t=418665&page=2

And the hood is only 12 inches above the kettle.

I am getting a HUGE amount of water dripping back threw the Vent Fan !!!
http://www.amazon.com/dp/B005KMOJPK/?tag=skimlinks_replacement-20

By my calculations, if the Boil Coils is running at 100% for boil – I would need a 225 CFM vent fan
But I am not running at 100% for the boil – only about 65% = 143 CFM – and the fan is rated at 190CFM

There are several people in the “Easy &Cheap Vent Hood” thread doing 12 gallon boils – 10 gal batches
With the same 190 CFM fan, and not having the same problem I am…..

I have a run of about 2.5 ft. of the Flexible – Dryer – type 4 inch Hose up to a 45 degree turn to a Straight 4 inch pipe out of the house.
Total run is probably 5 ft.

I managed to wrap a towel around the fan to soak up all the water dripping.
And the fan managed to survive all the water, but it shouldn’t be dripping!?

I have a video of how bad the water in the fan is. I am attached a Movie - you can see for yourself how much water.
Do you see the water running around the edge ? Crazy !!!

SO the question is – am I not calculating the CFM needed correct?
I only have a 4 inch pipe out of the house – same kind of exterior hook up as the “Dryer Flapper “ vent you see everywhere.

Should I Switch to a 6 inch fan – and reduce at the exit point back to 4 inches? ( Back flow problem ? )
http://www.amazon.com/dp/B005XNNYMU/?tag=skimlinks_replacement-20

Basically going from 190 CFM to 460 CFM – almost 2.5 times the power !

Or add a “helper” in line fan to boost my total CFM ? And I stay with 4 inch – no reducer from 6 to 4…?
http://www.homedepot.com/p/Inductor-4-in-In-Line-Duct-Fan-DB204/100073963

Adding 65 cfm to 190 cfm = 255 cfm total = not a huge help I agree…. But a cheaper option.

Or could it be the temperature doing all the condensing – thus resulting in the rain in my fan ?

It was 60 F in my basement brewery
It was 25F outside

How is everyone else getting all that steam outta your basement brewery ?

Thanks in advance for all your help!!

What would I do without the HBT ?

Steve



View attachment vent movie.MOV

I have a 6" fan, but my fan is 5 feet from the hood. You can try moving the fan down stream and run 6" from the hood to the fan...if i boil at 100% i get condensation after 20 minutes. I took my fan apart and sealed the case with silicone. i have this one http://www.amazon.com/dp/B00KWYJQYA/?tag=skimlinks_replacement-20

steveoatley said:

And the hood is only 12 inches above the kettle.

Click to expand...

I would try it again with the fan 24-36" above the kettle. A little steam may escape to the room, but this time of year that might be a good thing. Or try it at ceiling level, maybe need to let it run for an hour or so after flame out to clear out the basement.

Did you have a window slightly open across the room to ensure enough make up air to get the cfm?

My 8" fan leaks a heck of a lot of condensation as well, but it's rotated 90° from your configuration and my fan isn't directly over my brew kettle. Your setup may be fundamentally flawed and you might have to think about adding an elbow to get the fan housing away from the brew kettle. I'm just saying.

Diverting the condensation seems like the obvious solution, but maybe there's no easy way.

I would try to heat the pipe so you don't get condensation. You can get pipe heating cable pretty cheap on Amazon. Or, at least try insulating the pipe. That alone might help a lot, especially if your basement is cold. If the pipe is hot, the steam won't condense there.

http://www.amazon.com/dp/B00002N6MB/?tag=skimlinks_replacement-20

So

Sounds like several of you think the Fan is to Close ??

And i was going to Insualte the pipe, after a few brews - but the down pour of water - I'm glad i didn't

Here is a shot - with proximity of Hood to Pot - and my dew rag.

I can't seem to get it to load the right way?

S

I'd turn it 90 degrees, thread (or JB weld) a small NPT barb and connect a tube to it to let it drain to wherever you can out of the way after moving it elsewhere.

It sounds like most gave you solutions. My take, likewise, is you have such high moisture, high temp air coming in, as soon as it cools slightly, a large amount of condensate forms. Either take in more dryer air (i.e. Bigger fan needed) to make all vented air less saturated , or put a drain line in as suggested.

Test for New Fan location

I moved the fan UP as close to the exit vent as possible.

I put 5 gal of water in my BK for a test - turned up the heat.
Turned on the Vent fan at 200F - Got to boil soon after
4 minutes in is was dripping

BUT important note
ALL teh dripping was at the FAN or POST Fan - the elbow out.

I silicone caulked the HELL outta that Fan
All the leaks were at Duct connections
except for 1 leak coming from the Power Box ??

S

I have a much larger fan well away from the hood (also a giant mixing bowl), its about a foot from the window vent hole and horizontally aligned. There's maybe 10 feet of 6" ducting and 2 elbows in between.

I still get a lot of dripping most of the time from the fan housing. I just put a towel under it. I keep meaning to make a little condensate tube to drain it, but the towel works for now.

I'd guess it is the giant increase in pressure across the fan. Vapor in a slight vacuum one one side turns into vapor in a high pressure zone on the other side of the fan and condenses.

Strange thing is, some days I don't have any dripping at all. Must be an ambient pressure/temperature thing.

steveoatley said:

Test for New Fan location

I moved the fan UP as close to the exit vent as possible.

I put 5 gal of water in my BK for a test - turned up the heat.
Turned on the Vent fan at 200F - Got to boil soon after
4 minutes in is was dripping

BUT important note
ALL teh dripping was at the FAN or POST Fan - the elbow out.

I silicone caulked the HELL outta that Fan
All the leaks were at Duct connections
except for 1 leak coming from the Power Box ??

S

Click to expand...

Unrelated, but where did you find those tiny buckets to catch drips? This would be super handy to have.

I even installed a drip vent on the fan itself, along with 10 ft of hose
going to my sink

NOTHING, not a drop came threw the drip vent....???

I Boiled for an hour
I boiled off just a little more than 1 gallon
And got probably about 1 quart of leaking liquid - total
including the wet towels, and the drip age.

BadWolfBrewing said:

Unrelated, but where did you find those tiny buckets to catch drips? This would be super handy to have.

Click to expand...

They are very handy

http://www.amazon.com/gp/product/B00362QS1Y/?tag=skimlinks_replacement-20

Steve

Well for the MOST part I am happy - with test results - I can brew this weekend !

I also understand that Atmospheric Conditions will effect Dripping ! BadWolfBrewing

This test it was 60 F in my basement & 54 F outside
My First test it was 58 F in my Basement & 34 F outside
Very usual weather here in Michigan - I am planing ahead to 5 F next February brews

But, i still want to fix it.....
I am rocking a 4 inch 190 CFM fan now
I am going to move up to a 6 inch 460 CFM Fan

http://www.amazon.com/dp/B005XNNYMU/?tag=skimlinks_replacement-20

with 4 to 6 inch reducers - I know they create Back pressure - to keep with my 4 inch duct work
But going from 190 to 460 cfm should be able to overcome back pressure

2.4 times the POWER !

Unless we have any HVAC brewers out there reading this ?

Steve

steveoatley said:

Test for New Fan location

I moved the fan UP as close to the exit vent as possible.

I put 5 gal of water in my BK for a test - turned up the heat.
Turned on the Vent fan at 200F - Got to boil soon after
4 minutes in is was dripping

BUT important note
ALL teh dripping was at the FAN or POST Fan - the elbow out.

I silicone caulked the HELL outta that Fan
All the leaks were at Duct connections
except for 1 leak coming from the Power Box ??

S

Click to expand...

Placing the fan nearest the exhaust point and having the housing in a vertical orientation would be best. Another issue is the lack of insulation on your duct. I used flexible insulated duct and have very little condensation doing 10 gallon brews. I get an occasional drip from the hole I drilled in the bottom of the fan housing. The un-insulated duct cools the water vapor and condenses before it can reach the outside air. Insulating it will allow the temperature inside the duct to equilibrate with the temperature of the steam coming off the brew kettle. You can buy insulation in rolls about 6" wide that you could wrap around the duct or, as I did, buy insulated duct. I may have enough insulated duct leftover. If you're interested PM me and maybe we can work something out. The following is my set-up:

Part of this is understanding condensation in general. Moisture will condense on surfaces at or below the "dew point" which is the temperature where moisture in the air condenses out. It's why in the winter you may see condensation on your windows.

Any surfaces that come in contact w/ the steam that are below the dew point will have condensation form on them.

Another thing that can cause water to condense out of air is a drop in pressure. Sort of like how low-pressure systems squeeze rain out of the air. If you have a low-pressure area in your fan, and you do, if that pressure is low enough you'll squeeze water out.

How do you keep this from happening? One way is to keep all the elements of the venting system above the dew point temperature. What temp that is depends on the temperature of the air being pulled and the amount of moisture it holds. You could simulate this by putting a hard metal object in water at various temps to bring that object up to temp, then holding it above the boiling pot where the steam enters your hood and see if it condenses on the object. If it doesn't, the object's temp is above the dew point.

Others' comments on insulating the ducts and/or fan will help because that will allow the ducts/fan to rise in temperature, and you might reduce or eliminate condensation.

If I were to do a system like this--and I will someday--I'd use a hood whose edges extended past the kettle so if there were any drips, they'd drip not in the pot but somewhere outside its footprint.

Those who have suggested a 90-degree bend with the fan no longer above the pot have a good idea, IMO.

JBBrewing2's setup above incorporates almost everything: hood wider than the kettle, insulated duct, fan not above the kettle. It's nice!

JB_Brewing2 said:

Placing the fan nearest the exhaust point and having the housing in a vertical orientation would be best. Another issue is the lack of insulation on your duct. I used flexible insulated duct and have very little condensation doing 10 gallon brews. I get an occasional drip from the hole I drilled in the bottom of the fan housing. The un-insulated duct cools the water vapor and condenses before it can reach the outside air. Insulating it will allow the temperature inside the duct to equilibrate with the temperature of the steam coming off the brew kettle. You can buy insulation in rolls about 6" wide that you could wrap around the duct or, as I did, buy insulated duct. I may have enough insulated duct leftover. If you're interested PM me and maybe we can work something out. The following is my set-up:
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Click to expand...

JB Brweing

Insulating the Duct work is on my list, just last on my list
I am trying to reduce as much of the residual moisture hanging around
- so i only get a few drips - not measurable dripage.

I also need to see if i need everything to be 6 inch - fan & duct work
then i am going to insulate ! promise !

Thanks for all the input

JB Brweing - i may hit you up for that insulation, thanks for the offer

S

Mount a large fan right in the window, don't make a big effort to contain all the steam, just enough hood to direct the steam out the window fan. Build the simple duct out of blue foam glued together, and you will get almost no condensation.

My neighbor brews in the basement, and it's a small basement, he does it with a large propane burner, and no ventilation except leaving the stairway door open. He brews 5 gallon batches. He has zero problems with humidity, and none with CO. I do the same thing in the kitchen with 4.5 gallon brews on a cranked up propane kitchen stove. We both do 30 minute boils, and those boils are very vigorous. I sometimes do a 60 minute boil, and in that case, occasionally flip a window fan on to bring fresh air in as a precaution. That said, we live in a pretty dry climate.... South Central Montana.


H.W.

I have a similar setup, only I use a 780cfm exhaust fan/hood mounted on an articulating wall mount that allows the hood to be moved off to the side. The condensation drips from the center of the fan housing on to the tabletop, but misses the kettle.

Owly055 said:

Mount a large fan right in the window, don't make a big effort to contain all the steam, just enough hood to direct the steam out the window fan. Build the simple duct out of blue foam glued together, and you will get almost no condensation.

My neighbor brews in the basement, and it's a small basement, he does it with a large propane burner, and no ventilation except leaving the stairway door open. He brews 5 gallon batches. He has zero problems with humidity, and none with CO. I do the same thing in the kitchen with 4.5 gallon brews on a cranked up propane kitchen stove. We both do 30 minute boils, and those boils are very vigorous. I sometimes do a 60 minute boil, and in that case, occasionally flip a window fan on to bring fresh air in as a precaution. That said, we live in a pretty dry climate.... South Central Montana.


H.W.

Click to expand...

This is what I do... I made a 4 ft x 2ft hood out of foam board and hung it over the top of my window I brew in front of.. I open the top of my window and run a dual 12" window fan in it... I get no dripping at all this way.

Thanks for the Big Fan suggestions - but that is not an option for me

I have Glass Block windows in the basement, and the standard Dryer Vent
going out of one of the blocks ( see the pic )

I can barely get the 4 inch Vortex fan into the space
Nothing bigger will fit.

I am not sure i can get a 6 inch vortex fan to fit.....

Its that tight around the windows

S

Mongoose's dew point comments are possibly misleading. You are not concerned with the dew point temperature of the room - that is the temperature which the moisture in the ambient room will condense out (air has reached saturation). Problem is steam is already saturated, that is, at its dew point or darn near it. So any cooling (or pressure reductions) at all causes condensation, hence liquid build-up and drips.

One solution is to insulate the ducting such that the temperature change occurs more slowly. An infinitely insulated duct would hold temperature from one end to the other and no condensate would form. Of course this is not possible, so it's impact is real but limited.

The other solution is to pull in enough ambient air where that air can absorb some of the moisture at the new combined temperature. This would take a large proportion of air, hence the need for a big fan. You could calculate volume's required of steam and ambient given the temperatures, but I will take a guess and say you would need to pull >75% ambient/<25% steam. This is why large hoods with big fans are successful and small, localized hoods (such as mixing bowls... sorry!) aren't.

BrunDog said:

but I will take a guess and say you would need to pull >75% ambient/<25% steam.

Click to expand...

Yup - More Power !

I have ordered a 6 inch 460 CFM fan = 2.5 times more POWER than the
4 inch 190 cfm....

And possible the Biggest thing i can get in the Window 'area'

Not a lot of room to work in.

S

But you also need to draw in lots of ambient air.

this is the mess I was happy to avoid by just ducting out the lid of my pot and not making a hood at all.

Well PT you didn't avoid it. I am certain there is lots of liquid dripping back into your kettle.

BrunDog said:

But you also need to draw in lots of ambient air.

Click to expand...

I have provisions for Make up Air.

The house is only 3 yrs old - we had it built
And i had the Builder pre-plumb under the slab in the basement for my sink.
Planing ahead !

I asked him for a Vent in the Glass Block - BUT he put a 2" PVC pipe threw the wall
said that would be more than enough.... I tried venting threw that first = didn't work !

Going from a 4 inch fan to 2 inch PVC - didn't work - too much back pressure.

So I am turning that 2 inch into the Make up Air vent
I am plumbing it across the room, and dropping it down low to the floor
and I am going to attach my now Unused 4 inch fan - and use it as a SUCKer

Sucking air in from the outside..... So as NOT to suck it away from my Furnace - witch is 3 ft away...

Steve

BrunDog said:

Well PT you didn't avoid it. I am certain there is lots of liquid dripping back into your kettle.

Click to expand...

No sir, weep hole stops this.

The vertical section before your weep hole will have condensate, which drains back down. Even the slightest temp drop will cause condensation since the air is fully saturated. Now, the implications are really zero, as the water is probably very clean. Maybe your boil-off rate becomes a bit less.