Ventilation Problem

[marilover]

hi, folks,

I've recently assembled a two grow rooms cabinet for Veg and Flower.
The cabinet is 180cm(H)*140cm(W)*50cm(D)

Veg Room 120cm*60cm*50cm
Fower Room 180cm*80cm*50cm
the other area is fo utility and storage

250W HPS with a air-cooled hood with one 6" in and one 6" out

outlet :1*6" muffin fan 212CFM to draw the air of both room and light hood
inlet : passive, 5*2" PVC tubes, passing from outside the cab then to veg room, the Flower room then through the hood and at last with 6" ducting to the ceiling.


The ambient temp is around 76, when light on, the temp inside Veg Room is 86
,84 in Flow Room.

Is this temp rise norml?

I'v observed when I left the Flower room open, the temp in the flower room drops to around 81 with ligh on.

Is this becaue the air inlet is too small for the outlet?

the inlet area is 5*30square centimeter=150square centimeter
the oulet areis 6"=182 square cnetimeter

Thank you bros

 

[wsp]

Temp rise is normal with the HPS. Make sure the intakes are at the lowest point. Where is the temperature measuring device located? If the device is close to the light output it will give you a false reading. 212 cfm sounds a little short for your cooling needs. With the extra turns it adds back pressure to the fan. Try using a fan for each room. Any fresh air entering rooms?

 

[marilover]

try to post some pics up,but failed
would try again

 

[marilover]

wsp : thanks for your input

here are some photos for better understanding

1)the cabinet closed

2)the flower room is on the left, utility room is on the upper right
,seedling cloning just below the utility, then the mother room. the lowest right is for storage. there are 4* 2' 24W T5 for each clone and mother room, the height for the clone is 37cm,mother is 76.

there are 2 2" pvc passive inlets on the wall in the clone room
3 for the mother room

the 5 2" are routed to the flower room

1 6" active outlet with 212cfm exhaust fan, no inlet on the back wall in the
flower room

3) this is the backside view of the cab

in the 1 st test run, 4 T5 are installed, temp in the clone room rise almost to 90, so in the following test, only 2 are installed, but still the temp is above optimal 85.

can't figure out how to fix it. need your inputs.
Thanks

 

[marilover]

the temp sensor is placed at the flower room bottom about 2' below the hood glass

 

[Guest]

Marilover-

If it was me, I’d cut holes in the floor of the cab & install the PVC pipe under the cab. From your pic, it looks like there might be room for it. If not, you could always shim the cab up a bit. Like someone else pointed out, it’s best to draw air from as low as possible. Also, have you checked to make sure you are not leaking light from the veg chamber into the flower chamber through those vent ports?


Bh

 

[marilover]

Bipedalhominid

If it was me, I’d cut holes in the floor of the cab & install the PVC pipe under the cab. From your pic, it looks like there might be room for it. If not, you could always shim the cab up a bit. Like someone else pointed out, it’s best to draw air from as low as possible. Also, have you checked to make sure you are not leaking light from the veg chamber into the flower chamber through those vent ports?

>>>>>>>>>>>>>>>>>
Bipedalhominid : nice to hear from you

i've tried to open the flower Room (FR) door with the clone R (CR) door closed when light on, the temp in the FR drop 4-5 degree F, while the temp in the CR rise 4 more. if i tried he other way around,no change in the FR but i got 3-4 drop in the CR. all the temp data are measured 30 mins later aft the door opened.

the temp sensor is place 1' under the two T5.

if i cut hole in the FR, i thinks i'll get the drop in FR but a rise in the CR?

any advise on where to cut vent to cure this pro?

as the light leak, have designed light traps with bending PVC tubes,not yet installed as u can see from the pic.

thanks

 

[Guest]

You need an inline fan, installed at the end of the run pulling exhaust air. The little fan you are using is the nemesis. They have 4" inline, but are useless if you expand. Go with a 6" inline, you can always use it in your future grows. Install a damper on the exhaust so you can control/reduce the air flow if needed.

By the way, that is a sanitary set up and the F/A PVC intakes are slick as the dickens.

Good Going

Ty-Stik

 

[Guest]

What is the temperature in the room where the cabinet is located? If you can control the heat in the room by closing the HVAC grills or turning off the thermostat in that room if it is a zone type heat system. Do it so the room air drawn into the cabinet is cooler.

 

[marilover]

Ty-Stik : I've a 212CFM 6" inline fan attached in the upper right ceiling of the cab in the FR, you can see it in the 2ed pic. There is also a spare 212CFM 6" inline fan installed in the utility romm right next the FR exhaust. Try runing both fans on extracting air through the FR and CR with little help, but louder noise,lol.

can only get sanitary PVC. What is F/A PVC? it's no good to use sanitary PVC?

Dont have HVAC system here, the room temp right now is somewhere around 25-27C or 75-82F. Thanks


thinking about cuting a few 2" hole in the bottom of back wall on the FR and CR to play around to see any diff. any better idea? i've read the threads by TheGhost with 250W HPS
which use only 2 4" inline fans delivering 75CFM only to raise 2C inside the cab above the ambient temp. with 2C (or 2F) number,feel my design is something wrong. He also mentioned that always have larger intake than the outtake. But i want to creat a negative pressure like the NGB style box to keep smell in control. Hummm............perplexing

 

[Pirate138]

as stated, make a few vent holes in the bottom and upgrade to a 250cfm fan. try to get your temps to 78F

 

[marilover]

Pirate138 : thanks for the tip, targeting 78F. will come back later when holes are cut and tested!!

 

[rastagrass]

marilover that is one fine cab where did you get it? and how much did it cost?