315W CMH Heat Issues. 3x3

[Nellyitis]

Hi Everyone,

Just recently purchased a Hi Par 315w LEC system with digital ballast. the ballast is separate outside the tent and their is no glass between bulb and plants. 3.1k

Now I was under the impression that heat isnt too much of an issue with them. I own a 3x3x6 grow tent with a carbon filter + 4" exhaust fan + air circulation fan at the bottom, and a fan pointing directly at the 315w. And I'm seeing temperatures of 90F in there! 180mm fan pointing directly up and at it..

Not to sure what else to do.. Any recommendations would be very much appreciated..

 

[coreywebster]

Heat is an issue with any light. Its a matter of wattage vs air exchange.
Is the 4" fan a proper extractor fan?
Does the heat get removed out of the house?
Are you measuring temps out of direct light?
Do you have plenty of passive intake holes for new air to come in?
What's the air temp of your ambient air before it goes in the tent?
What's the cfm of the fan and the filter?
Have you tried removing the filter temporary to see if it allows more air exchange and lowers the temp.

Did you have a different light before which worked with the same ventilation set up your now using?

 

[Coloradoclear]

You will need at least 170cfm fan to keep those temperatures down.

 

[Nellyitis]

Heat is an issue with any light. Its a matter of wattage vs air exchange.
Is the 4" fan a proper extractor fan?
Does the heat get removed out of the house?
Are you measuring temps out of direct light?
Do you have plenty of passive intake holes for new air to come in?
What's the air temp of your ambient air before it goes in the tent?
What's the cfm of the fan and the filter?
Have you tried removing the filter temporary to see if it allows more air exchange and lowers the temp.

Did you have a different light before which worked with the same ventilation set up your now using?

Hey mate,
The fan is 4 Inch HyFlo Boost Fan - Max 280m3/h + filter which is 300m3/h.
Heat goes directly to the window.
I measure the temperature in 3 different locations. Not much of a variance though..
I have the big rectangle passive opening down the bottom open. Just 1 open.
Ambient temperature is around 72F.
Shouldnt need to as its bigger than the fan If im correct?

Yeah I just had a 150W Meizhi LED.

Bit of a head scratcher..

 

[coreywebster]

Hey mate,
The fan is 4 Inch - Max 280m3/h + filter which is 300m3/h.
Heat goes directly to the window.
I measure the temperature in 3 different locations. Not much of a variance though..
I have the big rectangle passive opening down the bottom open. Just 1 open.
Ambient temperature is around 72F.
Shouldnt need to as its bigger than the fan If im correct?

Yeah I just had a 150W Meizhi LED.

Bit of a head scratcher..

The other day we had a guy who had a cheap filter and it was blocking 95% of the air flow, that's why I wondered if you had tried without yours, to see if it was causing to much of a reduction in airflow.

looked up the fan, seems like it should do the job. With that sort of exchange rate you should only see about 5 degree rise from ambient, maybe add a few more degrees not knowing the loss rate on ducting and filter. Should be enough though, clearly somethings not going as it should.

All I can suggest is check all ducting to make sure nothings leaking, open zips temporary and reset your thermometers and check it after a few hours. I assume the room the tent is in has some way to replenish the air been taken out too.
If you don't see an improvement try removing the filter and recheck temps again.

 

[Nellyitis]

The other day we had a guy who had a cheap filter and it was blocking 95% of the air flow, that's why I wondered if you had tried without yours, to see if it was causing to much of a reduction in airflow.

looked up the fan, seems like it should do the job. With that sort of exchange rate you should only see about 5 degree rise from ambient, maybe add a few more degrees not knowing the loss rate on ducting and filter. Should be enough though, clearly somethings not going as it should.

All I can suggest is check all ducting to make sure nothings leaking, open zips temporary and reset your thermometers and check it after a few hours. I assume the room the tent is in has some way to replenish the air been taken out too.
If you don't see an improvement try removing the filter and recheck temps again.

Interesting. I guess I'll give it a go, cant hurt.
Yeah I didnt think it was that bad. I see.

I've done quite a thorough check of the tent. But yeah big open window.
Thanks for all your help! muchos gracias. Hopefully I have some luck or I may have to look at an air cooled cmh hood. didnt want too though.

 

[Nellyitis]

@coreywebster not much luck, 1 degree difference without the filter..

Could I upgrade to just a 6" carbon filter and fan would that make much of a temp diff, or would an aircooled be a better path to go down. filter > hood > fan > out.

 

[coreywebster]

@coreywebster not much luck, 1 degree difference without the filter..

Could I upgrade to just a 6" carbon filter and fan would that make much of a temp diff, or would an aircooled be a better path to go down. filter > hood > fan > out.

Provided it is the fan just been underpowered or under performing then yeah upgrading to a 6" would be the best bet, you could go down the route of air cooled hood but if the fans really struggling now it may not be enough to get temps in range.
Typically you remove about a third of the overall heat with a hood. But you have more than doubled the wattage of lighting in your tent and its likely the fan was just keeping up before.
I would recommend rkv or ruck fans if they are available in your country. Its worth spending to know the fan handles the pressure needed to overcome the length of ducting and filter combined. Some cheaper fans may be rated high enough cfm, like yours is, but not all of them have the same level of drop off under any strain. Might be your losing 80% of the performance.

No reason you cant get this light and tent in harmony, to put it in perspective my old HPS and MH gear went to a mates with my veg and flower tent, the veg tent is 4x4 loft tent with only a 5" ruck fan, in summer it handles 600w of MH no problem and at the moment the dude who has it has 1000w in there and it manages fine and that's pushing through probably 10-15ft of ducting.

Just one other thing to check before you go buying anything. I have seen a few folks been ripped off lately with ducting, folks selling the inside of acoustic duct as actual ducting, problem with that is its perforated every cm with tiny holes.
I know its probably not the case but make sure your ducting isn't like that.
The shit people try and sell these days takes the piss.

 

[gwheels]

sometimes you have to open that intake vent on your tent a little to get the air to extract better. I ran a 315 in a 4 x 4 with a 6 inch vortex fan and it kept it max 78

Not related but true. Cheap filters suck. I would opt for a cheap fan and a quality filter.

Good filters allow a faster air flow and do a better job of odor control

 

[Nellyitis]

Provided it is the fan just been underpowered or under performing then yeah upgrading to a 6" would be the best bet, you could go down the route of air cooled hood but if the fans really struggling now it may not be enough to get temps in range.
Typically you remove about a third of the overall heat with a hood. But you have more than doubled the wattage of lighting in your tent and its likely the fan was just keeping up before.
I would recommend rkv or ruck fans if they are available in your country. Its worth spending to know the fan handles the pressure needed to overcome the length of ducting and filter combined. Some cheaper fans may be rated high enough cfm, like yours is, but not all of them have the same level of drop off under any strain. Might be your losing 80% of the performance.

No reason you cant get this light and tent in harmony, to put it in perspective my old HPS and MH gear went to a mates with my veg and flower tent, the veg tent is 4x4 loft tent with only a 5" ruck fan, in summer it handles 600w of MH no problem and at the moment the dude who has it has 1000w in there and it manages fine and that's pushing through probably 10-15ft of ducting.

Just one other thing to check before you go buying anything. I have seen a few folks been ripped off lately with ducting, folks selling the inside of acoustic duct as actual ducting, problem with that is its perforated every cm with tiny holes.
I know its probably not the case but make sure your ducting isn't like that.
The shit people try and sell these days takes the piss.

Hm I see, Might have to look at upgrading the fan... not too expensive. touche about the air cooled hood.
Yeah they sell them online, I'll look into them.. thanks for the advice. I brought a few things cheap at first, quickly realising it isnt the most ideal path to go down!
No shit.. thats crazy.. It gets to about 105F in summer, which it is atm. Hopefully i can get it down.

Ducting is all good..

Thanks for all your help, will make the necessary improvements!

 

[PrometheanLeaf]

How long is the duct running to exhaust from the window? And how many bends and curves in the ducting?

 

[Nellyitis]

How long is the duct running to exhaust from the window? And how many bends and curves in the ducting?

1.2M perhaps.. not very long! 3.

 

[MichiganMedGrower]

Try pointing the fan across the canopy and upwards to blow the heat off the canopy and up past the light.

I dont know but maybe pointing the fan direct at the lamp is forcing heat down before the exhaust fan can pick it up.

 

[Nellyitis]

Try pointing the fan across the canopy and upwards to blow the heat off the canopy and up past the light.

I dont know but maybe pointing the fan direct at the lamp is forcing heat down before the exhaust fan can pick it up.

Yeah I'm across that dude... I hear you though!
I've got 3 fans blowing up on a 45 degree angle just to keep me floating by till my air cooled hood and new exhaust fan + filter. should be laughing then.

 

[MichiganMedGrower]

Yeah I'm across that dude... I hear you though!
I've got 3 fans blowing up on a 45 degree angle just to keep me floating by till my air cooled hood and new exhaust fan + filter. should be laughing then.

I like 2 circulation fans one on each side facing the opposite to make like a vortex to help the heat rise and clear the lamp.

It is not ideal to air cool with glass under the bulb as it will cut the uv which is what makes the cmh so good.

 

[Apalchen]

I cool 2 3x3 with a 315 in each on at the same time with one 6 inch fan sitting in the middle blowing thru the carbon filter, it was the cheapest option at the time and has worked well. I know filters work better pulling but this has still worked for me and if any smell gets out I have another carbon filter I move around the house to sit by any particularly stinky tent (usually only need last couple weeks)


Also i tried a cheap 4 inch fan and carbon filter and it wouldn’t even cool my QB fixture. after you put a filter on a 4 inch fan I think it has almost no suction, atleast the cheap vivosun one I bought.