12VDC Fans: Intake or Exhaust?

[Dan97]

Howdy All...

In my 8x8 hardside, I'm going to install a three small 12vdc fans to help out the venting and circulation a bit. The house, not the heater, is vented in both corners, top and bottom of each wall with 2"dia louvered inserts. With an extra vent next to my heater. I heat with a Buddy heater and it warms up nicely but I'm still a bit concerned with the CO. I've never had the classic "portable headache" from this set up and I don't want to. It does get sort of cloudy inside when a couple guys "light up" at the same time. Also, since I have only single pane windows, I'd like to do something about the moisture as well. One fan will be dedicated for heat circulation. The other two for ventilation.

Now for the question... Do I mount the fans in the top vents. To push the "bad" air out. Or mount them in the lower vents to pull the "good" air in.

I'm leaning towards mounting them up in the top vents to push the "bad" air out. Any suggestions?

Dan

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[MNice]

Dan, I woult think natural convection would take care of the ventilation. This is based on mechanical codes that would permit this type of situation for combustion air in most States, but not MN. Speaking as a mechanical inspector, I would be comfortable with your setup in my oun house. Jeff

[cwmn]

If you feel you need to use the fans, I don't thik you do and it will be a great drain on what ever battery you use to power them, anyway, I would use them as exhaust fans that way its not blowing cold air in directly. On a side note, I am a smoker but I never smoke inside my shack, it creates a build up of yuck everwhere, I just "light up" whenever I need to check tip-ups.

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Have a good one!
CWMN

[Guest]

One exhaust output at the TOP and crack the doors at the BOTTOM if you wish to go with that set-up.

Otherwise I don't think it's all too nescessary.

Buddy Heaters are fine units. I beleive I will be investing in one for this winter.

PCG

[Dave]

I'd think you have plenty of ventilation, Dan. If you're still worried, buy a battery operated CO detector.

[Dan97]

OOPS!! I was wrong about the vents in my original post. As you can see the top vents are on opposite sided of the house. The (2) bottom vents (not shown) are on the wall opposite the door. In addition, I do get some airflow up from the hole openings. I got confused due to the house design that makes it possible to break the house walls down into (2) 4'x6'6" panels. Except for the door side which is three. Next time I stack them, I'll have to put them in the correct order. Not bad for a "first-try" house build, eh? If you're wondering about all the windows, Cindy was a bit claustrophobic. (sp?)

Dan

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[This message has been edited by Dan97 (edited 09-23-2002).]

[pulsar_nx]

I think the buddy has an internal oxygen sensor that cuts the gas off if their isn't enough air. I know mine has done that before and all I needed to do was open the door and it would let me start it again.

[Dave]

pulsar, you mean your furnace actually shuts down because there's not enough oxygen to keep the furnace flame burning? Are you the least bit concerned about that?! For YOUR safety.

[Guest]

Yeah, I would think that would indicate a dangerous situation.

Might want to check into some better ventilation.

PCG

[Fat Rap guy]

The buddy doesn't go out because there isn't enough oxygen to keep it lit, the sensor shuts it off. The sensor's pretty conservative.

[Grabs]

Well working in the electronics field, and working with many sensors I personally would not and will not put my life in the hands of a sensor of this type. Here's a question to you, how are you going to prove that the sensor didn't work right when you are dead? No manufacturing process can produce 100% functional units, do you wanna find out that yours is the "one"?

I am sure these are great units, don't get me wrong there, but use your own "good" judgment when it comes to proper ventilation, don't force the sensor to tell you you haven't provided enough.

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[This message has been edited by Grabs (edited 09-23-2002).]

[This message has been edited by Grabs (edited 09-23-2002).]

[Guest]

The buddy heater does not use any electronics to determine CO or CO2 levels, It is a simple pilot light with a thermocouple gas circuit. Nothing high tech about it really. In a more permanent shack, I would pair it with a battery powered CO meter/alarm, the vents on your house appear to be adequate, put a few more in if: moisture/smoke is a problem, you are concerned about it (or are getting high CO readings with the meter) but I think the battery powered fans would be overkill, and perhaps more trouble than benefit. With a heater unit and a couple of bodies, there should be a good convection current inside.

[Fat Rap guy]

The Mr. Heater company HSOforum says it's buddy uses an automatic low-oxygen shutoff system. It's "the first propane gas fired heater to be certified indoor safe by CSA international (formerly the American Gas Association) for small recreational enclosures, indoor use, and emergency heating." "The portable buddy features an oxygen depletion safety system that automatically shuts off the unit when the oxygen level drops below acceptable levels in enclosed spaces- which eliminates the hazard of carbon monoxide poisoning." It definitely uses more than a standard thermocouple.

[This message has been edited by Fat Rap guy (edited 09-24-2002).]

[pulsar_nx]

I'm glad it has it because it takes alot more ventilation than you might think would be nessary. I usally have both doors zipped down alittle bit to get the ventalation I need to keep it running. also can you say lawsuits? If it dosent work their will be some people calling their lawyer for compinsation. how many people do you know that really use carbon monoxide detectors. how did we live without all these saftey gizmos to prevent us form our own stupidity years ago? yes the sensor may where out someday because its mechanical but by that time I'll probibly have a better heater that puts out more heat to replace it.

[Guest]

I don't think that the buddy heaters manufacturer is worried about lawsuits. I'm sure that there is some fine print in that package. I have the sunflower heater for portable and the exhaust heater in the permanent. you guys ever considered just getting a heater with exhaust. Yeah Ok, it may cost a little more and be a little more hassle,.....but if you're that worried about your safety,....why not?

[Guest]

Fat Rap Guy,

Yeah, that is fancy techno-speak for a pilot light and thermocouple gas circuit fuel system. I know, I own one, no fancy electronic or otherwise sensors. Take a look for yourself, there is an exploded veiw diagram of all the parts and a parts list printed on the owners manual, open the box at your favorite bait shop or sporting goods store and see for yourself. If I am wrong, please point out which components I have been overlooking.

[musky hunter]

I would suggest that one fan blow in, another blow out. You can select the locations as you wish. I doubt that you're fish house is air tight, and most likely it'll work no matter where you put the fans. But you can't blow air into a coke bottle. The same with you're fish house. This way, you will know you are circulating in good air. If they are both just blowing out, and the house is quite air tight, the fans would be spinning but not be moving much air. You might think that it will cool down the fish house, but the circulated air must come from somewhere, and that somewhere is outside, whether it comes in through a crack in the door or through fan blades, it's still the same air.