Replace Propane DV Fireplace with free standing Harman Accentra - Can I use existing DV Pipe?

[rdavisvmd]

I have an existing DV Propane fireplace which is never used. I want to put in a Harman Accentra PS. There is DV Pipe which runs about 4' vertical and about 8' horizontal. Can I use this existing pipe or do I need to run a liner through it, or do I need to replace the pipe all together? I know I will need to most likely replace the exterior components meet install requirements.

FWIW, I am removing the FP insert and plan to line the space with Slate and put in a slate hearth to create a non combustible home for the stove for aesthetics.

Have found what I believe is a good deal on a new Accentra ($2500).

I would appreciate any comments and or recommendations. My biggest concern is if there is a fire hazard with the DV Pipe.

 

[Scoop]

You have to go by the stove manuaal and your local building and fire codes. Both of them likely require pellet vent pipe.

 

[imacman]

.....There is DV Pipe which runs about 4' vertical and about 8' horizontal......

Don't know for sure if you can use the same pipe with the pellet stove, but the 8' horizontal is going to be a problem, IMO.

You already have a EVL of at least 20, which automatically calls for an increase to 4" pipe, but the thing you will have issues with is a LOT of ash laying in that 8' horizontal pipe.....not good.

I also question how well that will draft.

 

[rdavisvmd]

Just demo'd the existing DV Stove. The previous measurements were a guess. Floor to Soffit is 7 feet. Center of Alcove to inside of wall is 5.5 feet. Total run to wall is about 12 feet.

 

[imacman]

Still not sure if the measurements you gave are the TOTAL length from stove to exhaust exit into the outside air.

Even with the dimensions you gave, it comes up with an EVL of about 14, and that is STILL borderline too long for 3" pipe. And that 5.5' horizontal is again an issue with catching fly ash.

 

[captkirk5858]

Propane direct vent doesnt get as hot as This will. My propane direct-vent hot water heater uses a blower into PVC and out. i had to check to see if this was correct. just looked really odd to me.

 

[rdavisvmd]

Thanks for the help everyone.

To simplify measurements, stove is on center, facing an inside wall at 5.5'. It will rise to 7' high, make a 90 degree turn to the right and exit a 2x6 wall exterior. I have removed an existing DV Propane Fireplace. I had brought my architectural blueprints to several Fireplace Stores before making this decision and all said no problem. Several stores recommended I just take a 3" flex pipe and run through my existing DV Pipe. I have found over the years retailers are willing to recommend shortcuts that do not really work. That is why I posted this question in the forum.


I have no problem with upgrading to 4". I have resolved so far that I will remove all existing DV Pipe and replace with Pellet Stove Pipe.


Is a 5.5' horizontal run too far? What is the best solution here. How do I mitigate the fly ash issue?

 

[imacman]

.....Is a 5.5' horizontal run too far? What is the best solution here. How do I mitigate the fly ash issue?

Besides re-locating the stove closer to the outside wall (which you may not want or be able to do), the only thing that will help is the increase to 4" pipe, and fairly frequent pipe cleaning with a brush & vacuum, IMO.

 

[rdavisvmd]

Would it help to add a slight incline to the pipe, I may be able to rise v run - 4" x 5.5"?

 

[jtakeman]

Any horizontal run longer than 2 feet isn't recommended. If you can add some pitch to the run you might be OK.

Is there anyway to get the stove closer to the exterior wall?

 

[imacman]

Would it help to add a slight incline to the pipe, I may be able to rise v run - 4" x 5.5"?

Yes, but that won't change the fly ash problem much.

 

[rdavisvmd]

There is not a real easy way to move the stove closer to exterior wall without demolishing the entire chimney area and soffit. I would also have a door swing issue with the placement of the stove in that corner of the room.

The manual says you should not exceed 4' maximum run w/3" pipe. Center of the pipe to thimble will be 5.5'.

Does the 4" pipe help offset this issue? What is the major issue? Draft? Fly Ash Build Up?

I saw another manual that said max horizontal run for their stove is 10'.

What are potential issues here?

 

[rdavisvmd]

Thought of a different approach. If I put in two 45 degree angles, I would have 35" of horizontal run, and about 36" of diagonal, and the rest vertical.

Thoughts?

 

[imacman]

Thought of a different approach. If I put in two 45 degree angles, I would have 35" of horizontal run, and about 36" of diagonal, and the rest vertical.

Thoughts?

rdavisvmd, I don't think that is going to change much....kinda like "robbing Peter to pay Paul". Here are the figures for EVL (equivalent vent length)....you can do the figures for yourself, but as Jay said earlier, most stove companies recommend no more than 4' of overall horizontal:

1' Straight vert. pipe = EVL of .5
1' Horizontal " " " 1
45 degree elbow " " 2.5
90 " " " " 5

As for the diagonal pipe, split the difference between vert & horiz which means that would be EVL of .75

Add-up ALL the bends,straights, and diag.....anything with EVL close to or over 15 needs 4" pipe.

 

[rdavisvmd]

Imacman, I appreciate the help.

I have already decided I am using 4" pipe. That is not the question.

Can I use the proposed set up and provide for the appropriate draft and not create a fire hazard.

My Thoughts - Hopefully I have my geometry right here, I do not have AutoCad at home.

Current Option:
3' Horizontal - 3 EVL
3.5' Diagonal - 2.5 EVL
3' Vertical - 1.5 EVL
90 Deg Elbow - 5
2 45 Deg Elbow - 5

Total EVL: 17

Previous Option
5.5' Horizontal - 5.5 EVL
6' Vertical - 6 EVL
2 90 Deg Elbow - 10 EVL

Total EVL - 21.5 EVL

It seems like the 45 Deg Angle Option reduces the EVL, however it still needs 4" pipe. It seems like this is the better option if it works.

 

[imacman]

Previous Option
5.5' Horizontal - 5.5 EVL
6' Vertical - 6 EVL
2 90 Deg Elbow - 10 EVL

Total EVL - 21.5 EVL

It seems like the 45 Deg Angle Option reduces the EVL, however it still needs 4" pipe. It seems like this is the better option if it works.

You used the wrong figure for the vertical....it should have been 3 EVL, which brings that one down to 18.5.....not much difference, IMO.

Again, IMO, this is NOT a great vent set-up for a pellet stove, but the final decision is obviously up to you. It may work out fine....just keep the pipes that aren't vertical clean.

 

[rdavisvmd]

Thanks, I knew that seemed too easy. I appreciate your help.

I do not want a set up that is a fire hazard, I do not mind cleaning a bit more than usual. I also do not want to set up a system that will not burn efficiently either.

I need to make some tough choices I guess. It is a alot of work and $$ to create this set up for it not to work. I have already purchased the stove so I am committed one way or the other.

 

[Countryboymo]

I have a 4' horizontal section that over 3' is outside under my deck stairs going to vent out far enough to be legal distance from the deck. I just turn the combustion fan on and stuff the shop vac hose up the vertical section at the T 2' or so and blow out the horizontal section a time or two per season and at the end. I don't get as much built up in mine as I figured I would considering. Every stove is different and every brand is different but I would bet you would need to set yours up to easily do the same thing.

 

[captkirk5858]

And every Pellet Burns Diferent...

 

[summit]

what brand of dv pipe is it? selkirk's dv pipe is listed for use w/ pellets, has been for a while, not sure about how many others have only done so just recently. The selkirk Direct Temp Pipe works great, however.

 

[rdavisvmd]

I was planning on using Duravent PV Pro because of the 1" clearance to combustibles. I will look at Selkirk.

Attached is a photo for those who have been following.