Indoor Air pressure when using a temp controlled fan? Please advise

[MrSparkles]

Hi Guys,

Hoping someone with the new system im running next year can answer our last question before the purchase

Im buying a Ruck 6" 150Mm Rkw150 Extractor Fan 460M3h to replace my 4" Ruck fan

The plan is to use a spare System air 4" fan rated at 175M3h for an inlet fan and the new 6" RUCK for exhaust. Usually no probs at all..

Now the fan has temp control which will be a great feature.. The System air 4" will only be on while the light is on but could the RUCK still slow down enough wiht the light on for the systemair to creat positive pressure?

I cant find any information on the lowest speed the 6" fan operates when the temp falls below the setting.
Any help very appreciated..

Thanks,
S

 

[tryptophan]

I am inclined to say yes. This is because if your extractor fan turns off or slows to the point that it is not removing at least 175m3h, which would be roughly 1/3 of its normal operating speed then the amount of air being brought into the room would exceed the amound being removed, thus creating a positive presure. One solution would be to ensure that the temp setting on your extractor fan is set to turn off at a slightly lower temp than that of the incoming air, that way it will not turn off. Not ideal in the way of temp control but it solves the problem.(i.e. the extraction fan is set to stop removing air when the rooms temp reaches 65 degrees, but the air being pumped into your room is 70 degrees, the fan will stay on because it can not lower the temp beyond the temp of the incoming air.) The other solution would be to install a second exaust fan into the system the is rated @ slightly higher than 175m3h that also runs only when the lights are on. This would maintain a neg. pressure. The third solution (and my favorite)would be to remove the intake fan all together because the removal of air by the exaust fan will create a negitive pressure in the room thereby drawing air into the rooms inlet ducting by way of physics.:thumbs:

 

[Muddy]

I agree, you won't need the intake fan. I think trying to use it in conjunction with the speed control on the new fan with be more trouble to balance than any benefit from it. I run a variable speed, temperature regulated fan controller on my exhaust fan. Whether running slow or fast it brings in sufficient air through a passive intake.

 

[MrSparkles]

Cool great thanks for the help guys.. I think the new much bigger fan will be such an improvement over the current 4". The intake fan is barely worth it anyway..

Cheers for the advice

 

[redevil]

The only issue I think i would have with my passive intake ( i have 150 mm 6 inches out) is if i went photoperiod since having open intake flaps would cause light leak problems with a totally dark period

Saying that i have 2 exhaust ports at the top of my tent, i use a straight out for my venting but there is another one which is L shaped, i.e has an almost 45 degree bend, i use this for cables at the moment but by it's shape i think it would allow air in with minimal ( or easily fixed) light leaking

 

[tryptophan]

TO RED EVIL: Yea a 45 degree angle is good way of preventing the light from entering through your intake, any port with a length of ducting that travels in a slight curve will prevent light from entering and would not have as much of a restriction on the air flowing through it as a direct angle would(less restriction=better air flow). Also if your intake is located at the bottom of the grow room, on the wall oposite your exaust port, which should be on the top due to the fact that heat rises and having the exaust higher makes for better air flow because you are not fighting with the nature of hot air wanting to rise, you will get much more of a complete air change in your room also known as better circulation.:thumbs:

 

[redevil]

Actually my user name should be reddevil, i made a typo when registering and not sure if i can change it

 

[tryptophan]

Red devil

Actually my user name should be reddevil, i made a typo when registering and not sure if i can change it

Ha, u know when I typed it the first time I wrote red devil then I posted it and read it, saw that I wrote red devil and that your user name was red evil, so I edited my post and put in red evil. Idk I asumed red evil was some sort of strain name like lemon haze or somthin. Not sure on how to change it u could always create a new profile if it realy maters that much to u. Anyway....:firedevil: ill b sure 2 get it right the next time.:thumbs: