OAK length

[Ogilvy]

How do / can you run an OAK when your stove is in the center of the basement (vented thru chimney up the center of house (60 yr old bungalow))?

To get to the outside wall i'd have to run about 15' of vent pipe. Is that okay or too long?

Stove is a Harman P38 +, old fashion manual light and walk away for the winter.

Stove works fine in current setup but would like to reduce some drafts in the house that may be caused by my stove setup.


thanks

Jamie

 

[hossthehermit]

I'm basically in the same situation, haven't found an answer to the question yet. Once in a while I think about trying to rig up something, then get sidetracked and don't do it. One of these days I'll figure a cheap temporary solution to try, so I won't be out much if it don't work. Been burnin' this way for 5 years now..........

 

[TheMightyMoe]

If your chimney has space you can run a fresh air vent up through the chimney and have it droop / intake from below the venting.

Also I don't think the length of an OAK matters.

 

[Don2222]

If your chimney has space you can run a fresh air vent up through the chimney and have it droop / intake from below the venting.

Also I don't think the length of an OAK matters.

No but if you are going 15' then it should be at least 3" in diameter

 

[SmokeyTheBear]

Actually the length is going to matter, it acts exactly like your exhaust does, it restricts air flow.

Like a vent you also need to keep the elbows to a minimum.

The saving grace is that it is easier to suck cold air than to push hot air it.

What was 3 and 4 inch venting becomes 2 and 3 inch OAK runs roughly.

 

[hossthehermit]

Gotta keep in mind, unless you insulate yer OAK, there will be issues with condensation dripping .......

 

[iron stove]

My OAk is around 12-15 feet, forget axactly. I used Harmans 2 3/8" for first 3-4 feet, then 3" Galvenized stove pipe for the rest. I have ha d a HUGE increase in efficency No longer pulling cold air into the house.

 

[TheMightyMoe]

Actually the length is going to matter, it acts exactly like your exhaust does, it restricts air flow.

Like a vent you also need to keep the elbows to a minimum.

The saving grace is that it is easier to suck cold air than to push hot air it.

What was 3 and 4 inch venting becomes 2 and 3 inch OAK runs roughly.

Makes sense.

 

[VTrider]

I'm in the same situation also, stove in basement - middle of house, want to add OAK and it would be around 18'. I've been asking / researching around for a while now and it seems the consensus is that a longer length will indeed have some sort of impact on airflow and many have recommended going all the way up to 4" in diameter (so as not to restrict airlfow) or at the very least, non-corrugated 3" pipe.

I do not have any options of retrofitting an OAK into the existing chimney flue, will have to exit through basement wall.

 

[iceguy4]

An idea...use 3 or 4 inch PVC and run it to the nearest outside wall in your basement...I'm betting condisation will be minimal with this setup...if its a long run, bigger is better

 

[Alain S. Prevost]

I have a pf100 in the basement - pulling a lot of 'conditioned' air through the intake...reducing efficiency, drafts, and heat in the basement decreases significantly. Basement is half finished and heating throughout entire basement areas....
---I have planned to install 5" galvanized 26/28gauge ducting (5' long runs each) from the outside penetration - through the cement bulkhead/wall thimble - run 32' with two 90 degree elbows...down to a reducer to the harman intake.
This will minimize any restrictions with the intake being quite large. I found an intake assembly to mount on the bulkhead outside, looks like your typical wall vent from a dryer system with an inlet screen but no damper/louver.

I'll post a formula/calculation for restrictions in a vacuum pipe/intake with lengths/losses,etc once I find it in my notes.

I've heard of static building up with pvc products if not properly grounded....unlike a 'central vac' system which is grounded, and does not cause any issues. However I'd like to stick with galvanized ductwork for my install just because of access to a really accommodating local supplier I'll be insulating the ductwork as well .... 74degree 45%humidity basement air converging/radiating to 20degree outside air???? Def. insulating the ductwork to eliminate condensation.
I'll post pics in a week or so when its done. Going to use my manometer to measure the 'vacuum' the intake pulls now through 5' of 2-7/8" tubing compared to 32' of 5" ductwork .... hoepfully it is the same, if not elss restrictive.
If there are restrictions, I will upgrade my intake run to 6 or 7".

 

[SmokeyTheBear]

An idea...use 3 or 4 inch PVC and run it to the nearest outside wall in your basement...I'm betting condisation will be minimal with this setup...if its a long run, bigger is better

Ixnay to the PVC not code, not safe, and your installation will no longer comply with the makers installation requirements and so forth.

 

[iceguy4]

Ixnay to the PVC not code, not safe, and your installation will no longer comply with the makers installation requirements and so forth.

I stand corrected

 

[iceguy4]

BTW my OAK is working great... I am preheating my air from lost heat from chimney...

 

[Montnl]

Try EMT (Electric Metal Conduit) is lighter and cheaper than galvanized and the elbows have longer radius, for better air flow.

 

[ekarlis]

Hey Guys here is what I did. I took the vent window out of my glass block & put a 3" 90degree elbow.
I have a 12ft span & about half way I put in a 4" round fan with 3to4 galv reducers. It does not over pressure the stove. With the stove off & the fan plugged in, I get a low flow coming into the burn pot. I have an Enviro Maxx-M
& it works well for me. If anyone is interested, I can get pictures.

 

[iceguy4]

Hey Guys here is what I did. I took the vent window out of my glass block & put a 3" 90degree elbow.
I have a 12ft span & about half way I put in a 4" round fan with 3to4 galv reducers. It does not over pressure the stove. With the stove off & the fan plugged in, I get a low flow coming into the burn pot. I have an Enviro Maxx-M
& it works well for me. If anyone is interested, I can get pictures.

yes...pictures

 

[ekarlis]

IceGuy4:
Here are the pictures. Ask away with questions. I will try to help

 

[iceguy4]

does the duct fan run constantly?

 

[ekarlis]

Iceguy4: yes the fan runs constantly. I have it pluged into my surge protector. Here is anothor point, last summer I had my power company put a surge protector on my meter. On the outside pipe I put screen netting to prevent the critters from getting in. Also, with the fan running I get a clean burn & with out it running & the stove above #3setting you can see on the magnehelic gage that there are wide fluctions. This also depends on the type of stove you have. I just feel that a fan is necessary in long runs.