HVAC questions....

[smurfin'herb]

Ok, heres a few....

I have two rows of lights, and an 8'' fan connected to a 8x6x6 Y duct and then split off into the two rows at the beginning. And then at the end of the light chain, each row has its own 6in vortex fan pulling. My question is, will air still take the path of least resistance at the Y duct piece even tho there are fans pushing and pulling thru the lights?

2nd question.

By having put a 8x6x6 Yduct reducer on the 8'' vortex am i still getting more air flow from that than if i had just used a 6'' fan with 6'' ducting?

3rd question.

Does it make a difference if you put a reducer right on the fan itself or if you have it further away? I wouldnt think it would make a diff but i jus thought id ask..

4th question.

Anyone have experience with electronic dampers? Do you know how to hook them up to a timer? I was thinkin bout gettin some for these vents in these bedrooms, but i went downstairs and looked to see what size duct they were, and it looked like 6 but when measured looked like 7in, not sure tho... What size duct do you hvac guys usually use for bedroom heat/cool vents?

Well theres a start.. I really appreciate your help!!

 

[smurfin'herb]

whoa now, dont everybody jump at once! lol

 

[hoosierdaddy]

ANything will flow through the path of least resistance, and nothing will change that law of nature. However, there will only be a slight increase in air flow to the least restrictive side...all the air does not take one path.

Your 8" probably isn't losing half of it's potential (?750cfm), and is probably stronger than the 6" in the correct duct.(?450cfm)
One thing for certain, the 8" in 8" duct would be best.

I don't think it would matter where the Y is, if the paths are exactly the same it shouldn't matter. It would matter on what side of the fan it was on. Pushing would be a worse scenario than pulling through.

A damper is going to have a NO or NC connection. The thermostat (or controller) will reverse the situation of the wiring and cause the damper to energize. Which in turn causes the damper lid to move via a small motor (or solenoid). De-energizing reverses the action. (or visa-versa depending on if you are using the NO or NC wiring.)
Some may not have a NO NC option. In those cases I think they will be Normally Open, and when the contacts close, you energize the circuit, and the vent opens.

 

[TGT]

I would think your set up to cool should be sufficient considering you have three fans in total if I understood your description properly. The reducers are going to influence your air flow, but the three fan set up should compensate for this so I wouldn't worry much. Really all you have to do is see if it is cooling as well as you want it too and if so, I wouldn't worry about how efficient it is. If not then you should take a better look at it.

For the other question, it does not make a difference if the reducer is close to the fan or further down the chain. It still is reducing air flow. Something of intrest you might want to know, sometimes reducers are actually used to increase back pressure there by making a system more efficient. This is done in large cooling systems that have long runs or multiple vents connected to one larger source. This kind of gets a little in depth and is more than what we need for a smaller grow, but can be utilized for a larger commercial set up. In your case I don't think utilizing back pressure methods will increase efficiency but just wanted to mention it.

About the electronic dampers, I answered another thread about this same thing earier. I would try closing the heat vents at all times. It is okay for the room to get cool during the dark cycle. Usually 15 degree's celcius and sometimes lower is fine and can be good for the plants depending on the strain. I would put a thermometer in the room and see how low the temperature goes. If it is in an acceptable range just leave the dampers closed. If not you might have to open and close them manually as I have not heard of ellectronic dampers that connect to a thermostate, although they could quite possibly exist. If you find something like this, please let us know. I could use something like that also at my grows as I use the homes central air and heating.

Hope this helps a bit and good luck!

TGT

 

[hoosierdaddy]

http://www.discount-hydro.com/productdisp.php?pid=303&navid=29

http://www.homedepot.com/webapp/wcs...og.beans.EndecaDataBean@145475dc&ddkey=Search

 

[badugi]

Excellent posts, hoosierdaddy and TGT

 

[yamaha_1fan]

TGT, are you well experienced in HVAC? Seems like you are. I am going to be setting up a new room and am going to need some help in setting up the air cooling. 20-30 hoods per room.

Couldnt you use a thermostat and just use a relay to run the dampners?

 

[smurfin'herb]

Wow thankx for the great posts everyone. Im just gonna eat the dirt and put heaters in the rooms and close off the vents. When i have the house set on 68, the veg room gets down to 63 degrees at night, and thats too low cuz my day temps are at 72.5-75 degrees. Those dampers seem like you have to hardwire them to a timer, i only see wires and no male plug at all. I dont wanna deal with more wiring, or cutting any more f'ing rigid ducting with tin snips.lol So what im gonna do, is set the house thermostat to like 50 degrees, and then just put heaters in each room set to come on when the temp drops below 65. and then in in turn heat the room up until it reaches 72.5. sound like a good plan? do they make space heaters that you can preset temp ranges on like that? or do they just turn on once it gets cold and then turn off after a certain amount of time, or temp that is reached? i never had to use one.

 

[yamaha_1fan]

We just bought some space heaters and none of the ones we saw had a built in thermostat. Well they do have a number like 1-6 and when it gets to that temp, it turns on/off. But not an actual temp.

We bought some 1500 Watt heaters for $37 from Home Depot. We got two for the bedrooms and two for the veg/flower room

 

[PonicalChillin]

cutting any more f'ing rigid ducting with tin snips

smurf,

if your going to be cutting a lot of ridid in your days look into an air nibbler. I got one at harbor freight. Hooks up to a small compressor and cuts through ridgid like butter. Cheap too - only about $25.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96661

Very handy tool for the grow room.


peace
pc

 

[badugi]

I used a Dremel. Used a cutting disc, but should have used a cutting bit. If I had an air compressor, this nibbler might be handy; I don't, so I think a metal cutting bit would work well for light use.

(I got a Tungsten-carbide cutting bit now, pretty useful for other things as well.)

 

[hoosierdaddy]

Cutting with any sort of abrasive cutter, and in particular a high speed Dremel, leaves thousands of metal shards around, and can be very dangerous. Especially in the hands of someone who is new to fabricating metals.

The nibbler leaves nothing but one curled up piece of metal, or small chunks that can easily be handled and disposed of. And there is not near the danger of operator harm, or a fire hazard.

 

[badugi]

That's an excellent point.

I wore safety gear (eye protection is a must, and gloves help a ton), shop-vac'd the dust, and blew out the rest. But that nibbler sounds like the business especially after hearing it's not an abrasive removal process. Saw a quick video and assumed it was.





That wasn't fun.