# Boiler room venting



## dontilgon (Dec 6, 2009)

I just enclosed my boiler and waterheater. The room is approx 9x5 feet. the boiler is vented with a 6" smoke pipe with a a flap that opens when the boiler kicks on. Its a oil burner, baseboard heating. I guess iam just worried that i may have sealed the room and it may be dangerous doing so. My thoery in enclosing the the boiler to it own room was to keep the boiler hot so the boiler would kick onless to keep the tempt up. The house is a basic ranch with an unfinisehed basement at the time. Hope this makes sense. Thanks for any help.


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## meboatermike (Oct 29, 2009)

How cold a climate do you live in? I am in southern Maine and my theory is that the boiler provides some heat to the basement so it will not be too cold down there. While I do not have any obvious air leaks into the basement I know that due to age of structure etc. my basement is not to tight for the boiler.:no:

You have both a boiler and water heater? If the room is tight I would think that you may need to bring in some make up air for it to function properly. A 5' x 10' room is not very large and I would think it would get quite toasty in there. 

You might want to ask this question in the HVAC section.


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## Scuba_Dave (Jan 16, 2009)

You do need air coming into the room for the equipment to function properly


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## dontilgon (Dec 6, 2009)

I guess I should off mentioned location. Its Ny climate. what do u mean by equipment working properly?


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## beenthere (Oct 11, 2008)

Yep, it needs combustion air.

Check what temp your low limit is set to(probably set too high). Thats what has probably been running your boiler so much.


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## dontilgon (Dec 6, 2009)

My low is 160 and high 180. Boiler pressure between 15-18. Should i leave the door open in the mean time until i get the vent. the ceiling is not closed so i think there plenty of ventilation.


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## beenthere (Oct 11, 2008)

Since you don't use the tankless coil anymore. No reason to have the low limit that high.

I'd set it to 130. It will cycle much less to maintain its temp then.

And cut some registers into the walls to let combustion air in. Before it soots up so ,much it plugs up the boiler.


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## zircon (Sep 24, 2007)

*carbon monoxide*

You need fresh air coming into the boiler so you do not DIE from carbon monoxide poisoning. Probably about a 100 sq in opening to the outside for that size boiler.


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## dontilgon (Dec 6, 2009)

WOW thats one way of putting it. So is the room to small for the boiler because I cant see how i would get 100 sqf vent


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## beenthere (Oct 11, 2008)

He said square INCH, not foot.

The room needs 50 cubic foot of free volume for every 1000 BTU's input. Or you need to have combustion vents/ducts.
The unfinnished area of your basement may give you the volume you need. So you may be able to just add vents/registers through the inside wall to get the combustion air you need.


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## dontilgon (Dec 6, 2009)

beenthere, if i lower the lower tempt to 140 will that effect the heating of the baseboards. Also thanks for clearing that up. I will pick up two vents tomorrow. I presume i need 2 one for outside wall and inside boiler room wall. Thank again for the help.


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## beenthere (Oct 11, 2008)

Not really. When the control gets acall for heat, it will bring the burner on and raise the water temp to the high limit temp.

Really suppose to install a high and low vent, so it would be 4. 2 for each side of the wall.


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## dontilgon (Dec 6, 2009)

High low vent? Did I get over my head building a boiler room. Not sure what you mean. I have 2 18x12 vents. I was going to install one on the back wall and one on the outside behind the boiler?


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## beenthere (Oct 11, 2008)

1 that is 12" above the floor, and one 12" below ceiling.

Prevents Co or CO2 from being able to build up in the room incase of chimney problems.

The 12X18 are big enough in size by themselves. But, won't allow natural air exchange if the chimney is blocked.

Your second grille set doesn't need to be as big as 12X18.


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## dontilgon (Dec 6, 2009)

I turned the low temp down to 140 this morning and Iam getting alot of banging in the pipes now, There is no air in the line because I tried bleeding and it was fine.


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## beenthere (Oct 11, 2008)

Should be from just lowering the low limit temp.
Are you sure you didn't bump the high limit and raise it?


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## dontilgon (Dec 6, 2009)

positive.If the temp was higher then 180 would that cause the pipes to make that banging sound


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## beenthere (Oct 11, 2008)

Depends how much higher. And what pressure the system was at.

At a low pressure. the water could start to boiler depending how high over 180 it got.


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## dontilgon (Dec 6, 2009)

Pressure is 15-18 all the time i look at it. I left it 180-160. Seems to be fine, but my baseboards were always alittle noisy. Sorry but another question, the oil tank has been moved above ground and when they did so(prior owners) the oil line from the tank was 1/2 O.D then went to 3/8 midpoint to the pump. I changed at mid point 1/2 o.d to the pump. Basically its all 1/2 is that OK.Also any clue what BTU this might be, all the labels are worn. The house was build in 90 so it should'nt be that old.


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## beenthere (Oct 11, 2008)

The 1/2" is fine.

Just from the looks I can't tell.


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