Quick electrical help for frags

[scuba_steveo]

I am going to install a vent in my fish room to suck out the hot air. I plan to run some vent duct through the attic and attach it to a big exhaust fan. There is a fan there right now but it does not work. So I need to take it down and either try to replace the motor or just buy a new fan that will fit. Before I take it down I want to disconnect the fan but it is hard wired into the breaker box and I do not know which breaker it is going to. So, I need someone who has an instrument that can tell me if the wires still have juice running through them as I flip the breakers off one by one. Or someone, that can tell me an easier way. Thanks for your help!

[Ed]

Sounds like all you need is a multimeter to check for voltage. You can get one at Harbor Freight for ~$5.

[aquadoc]

I have one. When would you want to do this. Just curious cause I want to do the same thing for the fish room that I am building.

[villjr]

You can probably rent one at HD or lowes. Also if you put a larger fan, you'll create a negative pressure and will have a hard time opening the doors if the air pressure isn't balanced. I'm sure you thought of this already though Steve. :P

-Ernest

[C.Mydas]

So, I need someone who has an instrument that can tell me if the wires still have juice running through them as I flip the breakers off one by one. Or someone, that can tell me an easier way. Thanks for your help!

For frags you can borrow Brian...if his hair singes its live...easy enough. :o :D

[villjr]

LOL :lol

[Bug_Power]

I've dealt with 110 it's not too bad. Lived with a few EE's before. Honestly you can just get some good leather gloves cut the wires with insulated pliers, just keep the white and black seporate. I watched these guys rewire my whole house without turning off the electricity...

I'm in no way an electrical expert, and never take any of my advice.

[alton]

TURN IT OFF!!!!!!! The last two people that I know of that died from electrical shock died from 120 volts. One was working in his attic and laid on a piece of romex that had a nick in it and they found him still hung up. And they other was trying to fix a water line that had busted and there was a short in the power conduit that fed the well. What is your life worth, please if your not sure call an electrical company or find someone qualified. If your not sure which breaker, turn your main off and install a disconnect switch a head of the fan and then turn your main back on. Per code you need one anyway. NEC Article 430.102 (B)

[Bill S]

A mutimeter is cheap. Just be careful! DO TURN OFF THE POWER. If all fails, do the work in the daytime and flip the master switch.

Here's the fan I got for mine new setup: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=4437111711&rd=1&sspage name=STRK%3AMEWN%3AIT&rd=1

It is VERY quiet - you can hardly tell it's on when you are right next to it. He has several different sizes too - but this one sucks a LOT of air. I connected it to a thermostat for attic fans. I bought it at Home Depot - about $15.

[scuba_steveo]

I have one. When would you want to do this. Just curious cause I want to do the same thing for the fish room that I am building.

Anyday after work or this weekend. Sending you a PM.

Bill, you think 70 cfm is enough?
I went to home depot and saw several of these. I was going to go with one that was 300 cfm or do what I am now considering and just hook it up to the roof top fan. There may be several ways to do this but I want it done right and fast.

[JimD]

If the fan motor is hard wired to the breaker and it hasent tripped, the motor may not be bad, usually when a motor goes bad its either a short in the windings or a bearings froze up, both will cause the breaker to trip. Look for an on/off switch at the motor, that and look for any loose connections or broken wires.

[scuba_steveo]

None of the breakers are triped and I do not believe the fan has worked for some time. I cannot find an on/off switch. The existing fan is 30 years old.
Here are my two options as I see them:

[Bill S]

70 cfm is huge - also remember I'm just venting an enclosed area above the tank. I'm only using this to vent excess heat. Also, my ballasts are NOT located here - I moved them outside under the eaves.

[JimD]

Starter cap my be bad. Youre gonna need somebody to put a meter on the motor to see if theres even voltage going to it. Does the fan spin freely if you push it?

[seamonkey2]

[quote="bstreep"]70 cfm is huge ?????

I'm sure i am wrong Bill, 70cfm huge?????

I got 1540cfm from the exhaust I got from HD for $54.00, and does the job better than expected, and I thought originally it wasn't going to enough LOL

Steve I think option 1 is best, if you replace the old fan with a #3 fan from HD, but the rigging of the duct may be a pain, if you want to stop by and check out the way mine is hook up, LMK

Jose

[scuba_steveo]

Cool Jose.


Does the fan spin freely if you push it? Yes.

I think my best bet is to remove the fan & motor and take it into the shop and see what's wrong with it from there. If it can be fixed I will do that since it is already made to fit the exhaust vent. But maybe a new one will have the same screw configuration and I can just replace it instead of fixing it. I will not know until I get the existing fan & motor down.

[aquadoc]

Use the multi meter to test the motor, and then test the capacitor. Start breaking down the systems electrical until you find the bad component.

[Bill S]

1540 cfm WILL impact your A/C costs! 70cfm is for a normal sized bathroom, to dissapate humidity while the shower is on. I can't think that even a big tank will make as much ongoing impact to a room as a shower constantly running would.

I'm not really interested in putting 80 degree air out of my house in exchange for 95 degree heat coming in to replace it (through walls, cracks,etc., that replace the air I put out thru the vent). DEFINE your problem first: is it humidity? If so, get a dehumidifier. Is it heat? How much? Is it easier/cheaper to cool the existing air than cool incoming (95 degree?) air? In my case, it's just a 7x2 foot area above the tank where heat builds up.

[GaryP]

Steve, did you get the drafting department to do those drawings for you?

[aquadoc]

Dehumidifiers are good butt also create heat as well, so you would be adding to the heat even more??? Steve don't you already have an ac or no? I would put it on a thermostat so when the heat gets to hot it would turn on, butt when cool it is not on. THat way you cut down on your air exchange in your house. Just my .02.

[GaryP]

Not only will you be pulling 95 degree air in, you will be pulling in humid 95 degree air at the same rate that the exhaust is blowing out. Having a higher humidity in the house will impact the evaporation rate of your tank, thus making your chiller work harder too.

[scuba_steveo]

My problem is hot damp air. I am running 4 – 400W bulbs on an HQI ballast so each one is running at 430W so my halides alone are producing 1720W. Add ballasts, other lights, and pumps and you got one hot room. I want to suck the air out. I do have a window unit a/c (12,000 BTU I think but it could be 8000 BTU) but it does not work that well. I think my best bet is going to be a combination of pumping cool air in with the window unit a/c and sucking the hot air out with a vent. So here are the two fans I am looking at. Option 1 is the large fan on the roof. I would use a fan like this one:
http://www.homedepot.com/prel80HDUS/EN_US/diy_main/pg_diy.jsp?CNTTYPE=PROD_META&MID=9876&com.broadvis ion.session.new=Yes&N=2984+7752&CNTKEY=misc%2fsear chResults.jsp
Option 2 would be a smaller fan placed in the ceiling above the tank and vent it outside using a fan like this one:
http://www.homedepot.com/prel80HDUS/EN_US/diy_main/pg_diy.jsp?CNTTYPE=PROD_META&MID=9876&com.broadvis ion.session.new=Yes&N=2984+7752&CNTKEY=misc%2fsear chResults.jsp
I think either one will work and be a cheap easy solution. So, what I am overlooking or missing?

[GaryP]

If the fan is pulling air out faster then the AC is blowing outside air in, the the rest of the air will probably come through the outside door to your fish room. What you could end up with is a zero sum net gain, at best. If the AC is set to recirculate the room air, then all the new air is going to come from outside. I believe an AC unit works more efficiently when its recirculating room air because the air is already cooler then outside air. MAAST needs to recruit an AC guy for stuff like this. I think the term the HVAC folks use for this is air balancing.

[villjr]

Steve probably the best thing would be to try and figure out how much total heat everything in the fish room is generating. Then how much cooling the a/c is producing, which apparantly isn't enough. I've done calculations for this type of problem before but can't find my files on it. I have some thermodynamics books you can look at.

[Bill S]

My math says for your lights, you need almost 6000 btu. Wow! That's a half a ton!

Gary, it runs most efficiently because it's cooling air that's already cool. For instance, if your fish room is at 85 degrees and you cool to 70 degrees, you are cooling 15 degrees. If you are cooling outside air that's at 95 degrees, you have to cool it down 10 degrees MORE. However, if the outside air is 80 degrees, you are better off using outside air.

[villjr]

Wow. 1/2 a ton. That is a lot for such a small room. So maybe a smaller fan right above the lights would be best. Even if your a/c is only producing 8000 btu's, if bstreep is correct, you are generating 6000 btu's. The a/c may be enough just have to exhaust the heat. If not I know some guys at York International and they could give you a deal on a 600 ton chiller. :o

[Bug_Power]

You can pick up a wall unit pretty cheap. I have one for my bedroom I got because I like to sleep in the cold. It was on sale at Lowes or HD and is 8000but with thermostat. It will turn blower and everything off when not needed. I would do that over an exhaust fan.

[hobogato]

he already has one of those for the fish room.

[brewercm]

Not to mention if you run too large of a fan you will build a negative pressure in the room. What this means is every time you open the door or any other crack where air can get in so will dust and anything else that is in the other areas. Standard dust and all is probably no big deal just make sure that if you use anything like bug bombs or pest companies come to spray adjacent areas that you turn the fan off during that time.

[scuba_steveo]

The window unit A/c that I have is not enough.
I need to suck out the hot air also.
I understand that I will cause a negative pressure in the room if I suck out more than the A/C blows in but as long as it is not a big pressure difference I think it will be alright.