proper fan speed.

I'm running a ventech 4 inch inline fan and filter. I don't have a speed controller. I'm getting smell leak. I ordered a variable transformer. A good one not the cheap one. At full speed I'm assuming air is moving to fast for odor removal.

Will slowing the fan down help with smell?

Usually there can be only a few things that cause smell leaks.

1. Positive pressure - too much air going in and not enough going out. Forcing the air out of any areas that it can.

2. Fan too powerful for the filter. Causing air to pass over the carbon bed too quickly and thus not be scrubbed.

3. Clogged pre-filter - pre filter sleeve clogged with dust causing a smaller surface area for air to pass through.

4. Age of carbon filter - filter is too old or surpassed its useable lifespan.



J

Ventecg is a pretty cheap filter. Get a quality one for quality results. I use phresh.

You can try slowing it down though.

jondamon said:

Usually there can be only a few things that cause smell leaks.

1. Positive pressure - too much air going in and not enough going out. Forcing the air out of any areas that it can.

2. Fan too powerful for the filter. Causing air to pass over the carbon bed too quickly and thus not be scrubbed.

3. Clogged pre-filter - pre filter sleeve clogged with dust causing a smaller surface area for air to pass through.

4. Age of carbon filter - filter is too old or surpassed its useable lifespan.



J

Click to expand...

I know ventech is cheap but some say a good product. There is no positive pressure. The fan sucks through filter and blows out of the cab. With an intake hole. It is a 25in x 48 x 72in. Oak cabinet. Brand new setup.

mrblu said:

Ventecg is a pretty cheap filter. Get a quality one for quality results. I use phresh.

You can try slowing it down though.

Click to expand...

I was thinking of buying a phresh and gutting the ventech to make an exhaust muffler.

My hydro store offered me an mountain air filter for $100. It was an 8 in . I didn't have enough at the time but I will go back and pick it up next week.....

I know my filter listed air flow specs, which i take it as meaning you need at least a .1sec contact time for the carbon to work. Are you pulling or pushing with the fan? Ventech doesn't list detailed specs..only a 210cfm rating..I'd be a little wary of that.. I'm thinking the filter is underrated or you have leaks.

Here's what i got, I run a 440cfm 6" fan at 50% which keeps me just above the min airflow requirements, I'm slightly over at 100%, but not enough for me to worry about, I haven't had to run 100% yet..

Can Filter 66 Specifications
Max Recirculating (Scrubbing) CFM: 824 cfm / 1400 m³h

Max Exhaust CFM: 412 cfm / 700 m³h
@ 0.1 sec contact time
Recommended Min Airflow: 206 cfm / 350 m³h
Prefilter: Yes
Flange: 6", 8", 10"
Dimensions: (with pre-filter)
·Outside Diameter: 30cm / 12"
·Height: 66cm / 26"
·Total Weight: 20kg / 44lbs.
·Carbon Weight: 14kg / 31lbs.
·Carbon Bed Depth: 5cm / 2"
Max Operating Temp: 80ºC
Pressure drop at max cfm: 180pa / .75"wg

figure your "cfm's" for you space - there is a formula for

I need less than 200 cfm. There is no leaks. It is a negative pressure cab. If there was a leak it would pull air through it. My fan is pulling air. Either the filter is crap or I'm running it to fast. I'll find out when the transformer gets here.

The ventech fan is fine it seems to be quality and has a good warranty. I will order a phresh or can and make a muffler out of the ventech filter.

Now my question is on the can filter. The can 33 is rated double the cfm of my fan. Is that OK? @WeedFreak78
Never mind the can 33 is rated 200 cfm exhaust. So which is better can or phresh?

IDK which is better..I would think they are pretty much the same. I think you could get away with an slightly overrated filter as long as the min. airflow requirements are met. Your fan needs to overcome the resistance from the filter before it actually starts pulling air through. If t doesn't move enough CFM it will almost be like sucking on a closed/heavily restricted pipe. I think the Can 33 would work for you, your fan is rated at 190/200cfm - depending on which site you go by, ventech lists it @200cfm - the 33 has a max CFM of 200 for exhaust and a min of 100cfm, which would let you run your fan down to 50% or so..

Can 33 Specifications
Max Recirculating (Scrubbing) CFM: 400 cfm / 700 m³h

Max Exhaust CFM: 200 cfm / 350 m³h
@ 0.1 sec contact time
Recommended Min Airflow: 100 cfm / 175 m³h
Prefilter: Yes
Flange: 4", 6"
Dimensions: (with pre-filter)
·Outside Diameter: 30.5cm / 12"
·Height: 33cm / 13"
·Total Weight: 11.5kg / 25.3lbs.
·Carbon Weight: 7.5kg / 16.5lbs.
·Carbon Bed Depth: 5cm / 2"
Max Operating Temp: 80ºC
Pressure drop at max cfm: 180pa / .75"wg

Recommended Can-Fan:

Fan Watts Consumed Filtered Air CFM
Can-Fan 6" HO 137 Watts 232 CFM

Can-Fan 6" 81 Watts 178 CFM

Can-Fan 4" HO 78 Watts 130 CFM

I just did some math 2ft x 4ft x 6 ft ( your box dimensions, correct?) = 48cu ft, which means you only need something like 16 cfm in order to do a complete air exchange every 3 mins. I think you're moving the air too fast and it's doesn't have the contact time with the carbon to be scrubbed effectively. IDK what a good solution to a small cab is.. might want to go to the micro/stealth/cab sub-forum.

WeedFreak78 said:

I just did some math 2ft x 4ft x 6 ft ( your box dimensions, correct?) = 48cu ft, which means you only need something like 16 cfm in order to do a complete air exchange every 3 mins. I think you're moving the air too fast and it's doesn't have the contact time with the carbon to be scrubbed effectively. IDK what a good solution to a small cab is.. might want to go to the micro/stealth/cab sub-forum.

Click to expand...

That is what I was thinking. Hopefully the variable transformer will be here in a couple of days. I'll try that first. Thank you for your time.

WeedFreak78 said:

I just did some math 2ft x 4ft x 6 ft ( your box dimensions, correct?) = 48cu ft, which means you only need something like 16 cfm in order to do a complete air exchange every 3 mins. I think you're moving the air too fast and it's doesn't have the contact time with the carbon to be scrubbed effectively. IDK what a good solution to a small cab is.. might want to go to the micro/stealth/cab sub-forum.

Click to expand...

Hooked up the variac and turned the speed down to 50% and works like a charm. It was moving air to fast.

Well that didn't last long. Just ordered a phresh filter two day shipping. Live and learn I guess.

what happened?

WeedFreak78 said:

what happened?

Click to expand...

Smell started coming through again. Ventech filter is just cheap. Their fan is OK.

Good luck with the fan. The one I had lasted about a month working fine, then bearing started to fail and was running pretty rough until I replaced it with a better brand (tjernlund was my choice.)

nomofatum said:

Good luck with the fan. The one I had lasted about a month working fine, then bearing started to fail and was running pretty rough until I replaced it with a better brand (tjernlund was my choice.)

Click to expand...

I've been using the fan for a while. They come with a 3 year warranty. I also have a good mechanical background if it fails I'll take it apart and order a bearing from Grainger's or fastneal.

Just an update. I took the ventech filter out and installed the phresh. The room got smelly while open.

Within a few minutes the room was cleared and smelled fine. Night and day difference. Phresh filters are good.