Regency Greenfire GFI55 - OAK but not on an exterior wall

Hello all,

This is my first post, allow me to introduce myself. My name is John, from central Connecticut and last fall I had a Regency Greenfire GFI55 pellet stove (insert) installed in my home. The home is a raised ranch, the stove is located on the upper level in a centrally located fireplace (not on an exterior wall) where its job is to heat roughly 1800 sq feet on the upper level. The three largest rooms have 14 foot cathedral ceilings where I'm sure much of the heat likes to be trapped. I installed a ceiling fan in one of these rooms to help circulate air, but it isn't feasible in the other 2 rooms to install fans. Last winter, a particularly cold one, we went through 5 tons of pellets. I'll also mention that I installed a thermostat for the stove and use the hi/lo setting to maintain 68 degrees. The thermostat is in an adjacent room so the stove output doesn't skew its reading of the ambient temp. On the coldest of days the oil boiler had to do some work to keep the rooms farthest from the stove comfortable but for the most part the stove performed well (we used about 275 gallons of oil in addition to the 5 tons of pellets). The home was built in 1986 and is a bit leaky. I did a lot of "homework" last year to learn how to run the stove optimally, what a proper flame should look like and how to regularly clean and maintain the stove. This spring I cleaned the steel chimney liner and found that I should have really cleaned it at least once mid burning season. The combustion fan was also very dirty and could have used a midseason cleaning.

The reason I am posting is because of how drafty the home can feel when the stove is running. It seems that it prefers to pull combustion air from around the front door and consequently that passes right over our living space where the draft can be felt. It seems an outside air kit would remedy this issue. However, as the stove is located in the middle of the home and not on an exterior wall it seems almost unfeasible. Beneath the stove is a finished room so I cannot simply route a pipe out through the basement. Is there any such outside air kit that utilizes an additional pipe up the chimney? That is the only feasible path to fresh air that I see. Would this be considered safe?

Thanks for reading.

Thank you for taking the to reply, and for the very thorough reply at that.

I also read the post that you linked with the specifics of your setup and particularly the use of a 2nd pipe for the OAK - which of course interested me the most. So, I'm glad to see it can be done, has been done, and seems safe.

I didn't mention in my earlier post that my insert is installed in a prefab fireplace. For anyone that may not know what that is, a prefab is a less costly alternative to a typical masonry fireplace. A prefab typically consists of a sheet metal housing or firebox, firebrick lining within the firebox, glass doors and steel liner rather than a masonry chimney (which I believe is also referred to as a zero clearance). So, no masonry chimney in my house. Instead, I have what looks like a 8-10" steel liner clearanced from the wood structure so as to not be a fire hazard. Within that 8" liner, the 4" stainless pellet liner was installed. It looks like it would be a very tight fit for another 4" liner for an OAK. If I could get away with a 2" OAK pipe that seems like it would be ideal, but that may be too small. The intake on the back of the stove is only 1.75". A 3" OAK pipe MAY fit ok but would be tight. I assume it would be OK for the OAK and exhaust pipes to be in contact with one another in their run up to the roof.

I wouldn't go back to my retailer/installer to have this done. To be honest, I was very disappointed with the quality of the install. I won't mention the business name but I can say that in the store they told me they would install themselves but when the time came they hired an outside contractor. The contractor seemed to only be interested in getting it done quickly and not correctly. In addition to not adjusting the hopper size, they didn't bother to properly secure the chimney cap after installing the liner, installing only 2 of the screws previously used and leaving the remaining screws on the chimney top. I am also very much a DIY person.

I guess the main questions I have are, for one, can the OAK and the exhaust pipes be contact in their run up the chimney? Can I get away with using a 2", 2.5" or 3" OAK pipe considering the intake pipe on the stove is 1.75"? Since the OAK needs to terminate 6" below the exhaust, can the OAK terminate while still inside the chimney?

thanks again!

Thank you both for the replies - I really appreciate your shared experiences and recommendations.

I can say that my chimney is not sealed between the pellet liner and the fireplace liner. The pellet liner sticks out of the zero clearance liner and there is no sealing between the two. I can stick my arm right down the ZC liner beside the pellet liner. The original rain cap was reinstalled on top (this is the part the installer decided that only 2 of the 10 or so screws were required!).

If Alan of CT Wood Pellet Service (Berlin) is in fact the place I googled then their store is only a 10 minute drive for me and I'll have to stop in.

I'll try to muster the energy this evening to get the ladder out and take a few pics at the chimney for better reference.

Thanks again.

I made my way up to the roof this evening to take a picture of the termination of the pellet liner within the zero clearance liner. As you can see, nothing sealing off here, just a jagged cut and the liner sitting within the liner. In fact, there is nothing at all securing the pellet liner other than its connection to the stove. From what I read above, it sounds like there should be something sealing the space between the ZC liner and the pellet liner.

the picture looks rotated on my screen, so if this looks like a horizontal termination that is not correct. It is vertical.


I didn't take the cage off the chimney cap, but eyeballing the ZC liner it looks to be 10 inches, maybe 12. Large enough that I should be able to sneak a 3" liner down there without a problem for an OAK. I found a decent price for a 3" stainless liner on Amazon. To make this work the exhaust would need to terminate at least 6" above the intake, that shouldn't be a problem to achieve with a new cap that adds height. Can a similar, but shorter, cap be used for the OAK to keep water and birds out?

What I cannot seem to find is any kind of sealing cap that would seal the space around the 2 pipes within the ZC liner. I imagine that is something that could be made fairly easily using sheet metal. If that is an acceptable method, would galvanized sheet metal be ok? Would it be acceptable to use high temp silicon to seal it?

One thing that is nice about the zero clearance is that it is located in the middle of the house, meaning 2 rooms on opposite sides of the house have access to the ZC. What that means, is its really easy for me to access the back of the stove by simply opening the doors in the room that the face of the stove is not located.

Thank you all - I have reached out to Al.

I just wanted to stop back in and thank everyone for the responses and recommendations. I had quite a few emails back and forth with Alan and we were able to come to an agreement. He will be installing an OAK through the chimney vent and modifying/sealing the chimney cap.

Yes, I'm looking forward to having it done correctly. A boost in efficiency would be great but difficult to measure. I'm at a crossroads this season between burning oil or pellets with the current depressed oil prices. I think it will be a combination of the two. Wouldn't feel right in the living room without the ambience from the stove! The dog may revolt too, he lives to plant himself by the fire.

Skier76, I am a former Wallingforder myself.

The work isn't done yet, so I can't really comment on how it went. I've only heard good about Al and in my emailings with him he came across as polite, interested, knowledgable and responsive.

I'd be happy to share my experience once the work is complete. That said, we don't have a time frame just yet as we haven't booked a time. I think I'll know more next week.

I believe his plan is to modify my existing chimney cap and construct a dividing wall between the two sides. I'm not sure on whether he has a website.

Drafts aside, logic dictates it should be more efficient to use outside air for combustion versus sending your just heated room air out the chimney and drawing in cold outside air through the leaks in the home. That said, I've read plenty and people make arguements for both sides.

The front door is a little leaky. I've installed thicker foam seals and that's helped but not entirely eliminated. I want to replace it altogether but it's low on the list.

Hi everyone, its been a while but I owe it to you all to come back and close out my thread.

Way back in September I had Alan come out to install an OAK. I had purchased a 3" stainless steel liner, 25' in length for him to use. He ran the extra liner up the flue and fabricated a top plate to seal it all up. He reused the existing chimney cap but installed a 90 degree elbow for the intake to feed from the side (with a hood), so there is no chance of pulling smoke in through the intake. Two things about the install that I like the most: first, the top is sealed, there is a steel plate with holes sized for the 2 pipes and some kind of caulking. Second, the pipes are both secured at the top - the previous install didn't secure the exhaust liner at the top and the entire weight of it (some 20') rested on the stoves exhaust flange which also meant cleaning it was a pain because when I removed it from the stove it dropped to the fireplace floor. The one thing I didn't like about the install - the plate at the top that seals it all up is not zinc coated, galvanized or any other type of corrosion resistant steel. It is mild steel. Within about a week, it was showing signs of surface rust. I spoke to Alan about this and he offered to come back out to paint it for me. As I was in the process of painting the house, I opted to take care of it myself. I used steel wool to remove the surface rust, a prepping chemical, a few coats of metal primer and paint. It still looks good today.

As for performance, well I just started using the stove about 10 days ago. I can verify that it does pull air from the OAK now. I know this because when I first start the stove as the OAK feeds the stove the OAK pipe gets very very cold from the outside air moving through it. As the stove comes up to temp, the OAK pipe warms up - I believe this is due to running next to/being in contact with the exhaust liner.

With oil prices so low I've been using my boiler in conjunction with the stove, so its hard for me to compare a performance or efficiency increase to last year. This fall I also more than doubled the insulation in my attic, from R19 to R49. It's also pretty early in the season and still pretty mild out. With so many variables changing from last year its apples/oranges to compare.

I'm happy with the work Alan and his team did. He's an extra nice guy and goes the extra mile to make sure its done right the first time. Could have sworn I had a few pictures of the work on my phone but can't find them at the moment. If I come across them I'll be sure to upload.

I want to thank everyone for their suggestions and posts. I'm sorry it took so long for me to come back and wrap this up. I sort of forgot about it until I started using the stove.