Venting for Harman P52i

Hello pellet stove venting experts,

I am in need for some good advice on improving/modifying the venting configuration on my stove. A "professional" dealer installed it April 2014 and as time passes by I keep finding all the stuff he did wrong (reading the comments on the forum helped a lot!). He charged very little, but also delivered very little, so I guess you get what you pay for he is no longer in business.

We had some issues with stove earlier this year that got resolved - at this point we are operational and actually are getting some good heat from the stove. But, I can only go up to feed rate 3 before pellets spill unburned into the tray and my house siding is taking a soot beating! I suspect this setup is just all wrong.

I have been talking to some local installers on what do to and got some ideas, but before I make any final decisions, I wanted to share this and see what you think. So here is our current setup and some pictures.

My fireplace box protrudes into my garage like this. Stove sits in a zero clearance box. The vent goes up about 4ft and then side vented about 6 feet outside:


As you can see, it only sticks out about a foot and is very close to the top of the window and siding. The OAK is at the same level (slightly above the actual vent termination):
Here is the termination outside:


Full height view:


I am not proud of this, I knew nothing when it was put in and trusted my installer to do his job. I am better educated now. So here are the questions:
1. How bad/wrong is this install?
As I said we are operational, but do you see any risks of even running as is right now? obviously my siding is not getting any better, but the stove is running fine. So my current plan is to finish the season and then address.

2. How would you address?
Some installers suggested to extend the vent by adding a clean out T and then take it up a few feet, or even all the way up - this will move it away from the window, make it terminate above the OAK and fix the siding issue. However, I am worried that by adding another extension on top of that 5-6 feet horizontal run it will make my venting even worse overall. What do you think? Is this a good direction?

Another option suggested was to abandon this vent completely and run a direct vent up thru the roof. I do have finished space above the stove, but its a closet so it can be done, but this will be much more involved and expansive to do - so I am not thrilled about it.

Any other ideas? let me know!

Thanks!

Irish916 said:

Looks like there are two things there. You terminate less than a foot from a window (even with the oAK) and less than a foot from the inside 90. Is there no room to move that termination to the right? Maybe go up and then terminate?

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We do have about a foot from the window, but it is marginal and then just about a foot sticking out. All the options are open right now, but I will only move it if an extension is not a good idea, and then if I do - maybe just go up thru the roof instead?

fmsm said:

i would go straight up and out.

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Is there a chance that extending the current vent will work? Or is that a sure recipe to choke the stove out? Is going up thru the roof the only viable option?

What I am struggling with is the fact that's its working. Maybe not as efficiently as it could, but it is. We are well on our way to burn 5 tons this season. One may say - if its not broken don't fix it.

But, again from all I read here, the setup seems to be wrong. Going straight up and out will cost a minimum of $1500 to do, which is equivalent to about a year + of fuel! So, given the cost - would you still do it (I cant do this myself, have to get a pro)?

let me clarify the options as I have seen very little feedback so far:

1. leave it be. if its not broken, don't fix it. learn to live with the siding soot and location of the OAK and clean it every year. but, is it OK/safe to do that?
2. Extend the current vent, taking it up. This will help the OAK location issue and soot, but I am worried it may over extend the vent spec choke the stove - is this a correct assumption given the data above? Cost here will be around $300 - $400 for parts and some labor. So this is a could be a good route, if technically sound?
3. Ditch the current vent altogether, build a new vent straight up, thru a fished area and our 40 year warranted roof. Investing over $1500 to do.

I would like to hear what multiple members of the form think about this puzzle, if possible? I am not a venting expert after all

MtDew said:

Could you just use a "T" at the current output location and just go up maybe 3 feet? That would help with the OAK and Exhaust being so close and get you away from the window.

We would need to know exactly what elbows, clean out T's and lengths of pipe you currently have install to determine the current EVL. From there we can figure out if just adding to your existing vent is possible.

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Yes, that is option 2 on the list of options. it would be good if that can work! Here is what I can tell you:
The stove is sitting in zero clearance metal box connected to about 4 feet of vertical vent. then there is a 90 degree elbow and we go horizontal for another 6 feet to the termination point (including the outside sticking out). This is a 4 inch Selkirk vent.

So will an extension be ok EVL wise? if yes, how far can we extend? ideally, I would want to clear the siding too - but that means going all the way up ~15 feet.

MtDew said:

is there a clean out or 90* elbow on the rear of the stove?

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No, not as far as I know. if goes straight up from the metal cage. The stove "plugs" into the cage. cleaning is done by pulling the stove out of the cage, then running a brush up to the 90* elbow and then from the outside to the elbow. Although you can also run a brush all the way thru when the stove is pulled out using a drill & brush. you cannot reach the actual vent unless you take both the stove and the cage out... I think its called a zero clearance configuration.

MtDew said:

Good thing is you are already using 4" pipe. I think I would try adding the cleanout T to the existing vent configuration and then extend it vertically. If you had 3" pipe the EVL isn't recommended to exceed a value of 15. If it does you are supposed to increase to 4" venting.

If adding the additional piping to your current configuration doesn't solve your issues and you decide to configure your venting straight up and out, you should be able to reuse most of the piping anyways.

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Thanks, this could be the very direction I may take. Two questions: given my numbers - what is my current EVL on my 4 inch vent (how do you calculate that?). Doesn't the long horizontal run factor in? based on that, what would be the max length for the vertical extension to stay ok? I need to figure out how much of a vertical extension I can/should add.

MtDew said:

I'm estimating you current EVL = 13 (you could have use 3" for EVL<15). With adding a clean out T and extending up 15ft new EVL = 25.5. I read somewhere you need to stay under a max EVL of 30 with 4" pipe. So you "should" be within range with the extension.

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Thank you MtDew, this is very helpful. I will get some proposals to fix at the end of the season and post the results.

Any other opinions out there? let me know.

So, I was getting some proposals and a couple of the installers (Harman dealers) said that the maximum horizontal run allowed by Harman on a 4 inch vent is 4 ft. max. Regardless of the total EVL... Since I have a 6 Ft horizontal run, it invalidates my entire veiling install as not correct and must be totally redone. No extension will be possible on the current setup, which only leaves the option to abandon the current vent and just go up (much more $$$).

is this a correct statement? max horizontal vent on a Harman stove should not exceed 4 FT?

From the Harman install guide:
4" PL Vent Pipe:
4" Pl Vent Pipe: 30 Lineal ft. Vertical*
4" Pl Vent Pipe: 14 ft. Vertical w/1-90o and 4 lineal ft. horizontal*

* Long runs of flex or PL vent pipe installed directly vertical from the flue
stub may require more frequent cleaning due to fly ash falling off inside
and collecting directly above the combustion blower outlet.
Any use of horizontal venting will require more frequent cleaning. It is the
responsibility of the installer to make sure the entire flue configuration is
accessible for cleaning.

I read this as more cleaning may be needed - not as unsupported venting setup.

Ok, decision made. We are going up thru the roof. If you are a Harman/venting PRO close to Northern VA and want to give us a proposal to do this, PM me.

Any recommendations on vent manufacturers? I currently have a Selkirk vent,, is that a good brand? Someone told me about secure vent or security vent (not sure about the full name). Dura vent seems to be popular. what brand is the best, if there is such a thing?