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GreenBeginnings

SMS controller-no negative pressure at low temps

Hi all,

does anyone have any experience with sms fan speed controllers?

i have a 1500m3 outtake and 500m3 intake and everything seems to work fine while the lights are on and the fans need to work,but when the temps drop the intake isn’t slowing down as much as the outtake.

i have the dials at 30% min 100% max &25c 

am I missing something obvious?

thanks in advance 

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Not sure what you mean by no negative pressure? With 1500 out and 500 in, its got to get that extra 1000 from the vents (if a tent), thus creating negative pressure. What have you got between the grow space and the extraction fan? maybe take the 500 intake away and check again.

 

Not sure what that has to do with the temps though. My sms hybrid has a temp sensor but I've never used it. I just adjust the min and max dials together when i want to change speed. I assume this means that any automatic regulation of the speed by the temp sensor will be overridden because I have both min max at the same value.

Edited by calif123

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I had this recently when upgrading my fans for 2x1000w gavita's.

 

I had a passive flap still open, once I figured it out & closed it, all was fine.

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Have a little play about mate these controllers sometimes take a little tweaking to get right.

 

From your explanation it sounds like its cutting down the extract far quicker than your intake , you could turn the dial closer to 20c and see if that helps it could make the decrease in speed more gradual , i think my controller is a few points off what its set at and took me a while to get it sitting right , check all flaps and openings mate just have a general play around :yinyang:

 

Farmer G 

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This may be obvious but i could be wrong.  Surely if your 1500 is working at 30% then thats equivelant to 500.  In this case then the intake and outtake are roughly equal so not producing negative pressure.

Surely the answer is to turn off the intake fan at lights off?  Then youll have 500 out take and passive intake thus restoring negative pressure.

 

Maybe im wrong.

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