Connecting flex pipe directly to stove?

[Gilly]

Hello all. I have a Harman Accentra insert I installed myself this August. Chose to go the better-safe-than-sorry route and put in the full liner (23 foot chimney). One thing I wasn't too sure about was the connection of the 4-inch flex pipe to the stove. The Harman manual states "be sure to use a starting collar to attach the venting system to the stove". I found that the collar that came in my flex pipe kit was too small for the Accentra's receptacle - would have needed a TON of caulk to get it tight. I asked my dealer and he said to connect the flex pipe directly to the stove frame receptacle.

I did so and have a nice tight seal now. Everything working fine.

Any problems with this? Why do you need a starting collar, as the manual states?

Just joined the forum and am enjoying learning so much from everyone - thanks!

Gilly
Accentra Insert
NW Rhode Island

 

[begreen]

main reason I can think of for a starting collar is ease of removal for cleaning. other than that I would think you are fine.

 

[recppd]

How's the liner secured in place? Clamp, screws?

 

[Gilly]

I have the flex pipe pushed into the collar on Harman's insert frame. Held in place with two screws and high-temp RTVed around lip.

No fumes, etc. at this point - seems to be working properly.

As I understand it I shouldn't have to disconnect it for cleaning - just pull Accentra insert out on its rails and then gain access to pipe through insert frame. I will probably climb up on roof and send a brush down while attaching bag to bottom of pipe at stove frame.

Thanks for you responses gentlemen.

 

[kd460]

Not sure if the rtv sealant is the way to go. I think max temps are 500 to 600 degrees for rtv. A better choice would have been stove sealant.

Do you think the hold of the screws in the thin liner is strong enough? (I don't know the answer). I wonder if stainless pop rivets would have been better? KD

 

[recppd]

I have the flex pipe pushed into the collar on Harman's insert frame. Held in place with two screws and high-temp RTVed around lip.

No fumes, etc. at this point - seems to be working properly.

As I understand it I shouldn't have to disconnect it for cleaning - just pull Accentra insert out on its rails and then gain access to pipe through insert frame. I will probably climb up on roof and send a brush down while attaching bag to bottom of pipe at stove frame.

Thanks for you responses gentlemen.

I'd be really careful when you go to move the stove around so you don't tear your liner. A quality starter collar actually sandwiches the liner between two sleeves so when you insert the screws the two sleeves compress and hold the liner tightly in place. It also acts as a mini-chimney, directing smoke into the liner and eliminating the need for furnace cement / sealant. I'm surprised your starter collar fit so loosely. Are you sure you used the correct size?

 

[Gilly]

Not sure if the rtv sealant is the way to go. I think max temps are 500 to 600 degrees for rtv. A better choice would have been stove sealant.

Do you think the hold of the screws in the thin liner is strong enough? (I don't know the answer). I wonder if stainless pop rivets would have been better? KD

I must correct myself - I used high temp mortar from DAP - comes in a full-size caulk tube. It is rated at 2000 degrees.

The Harman Accentra insert uses a frame (sort of like a 'cage') which is wedged very firmly into the fireplace. The vent pipe is connected to this frame which does not move. To service the stove, one releases some clamps and pulls the stove out on rails. The stove has a high temp gasket which mates up with the frame exhaust port as you push the stove in. When you pull stove out / push it in the frame shouldn't move more than 1/8 inch or so (it's in there very tightly).

So - yes I think the liner will be OK without being moved.

Thanks for your thoughts!

 

[Gilly]

I have the flex pipe pushed into the collar on Harman's insert frame. Held in place with two screws and high-temp RTVed around lip.

No fumes, etc. at this point - seems to be working properly.

As I understand it I shouldn't have to disconnect it for cleaning - just pull Accentra insert out on its rails and then gain access to pipe through insert frame. I will probably climb up on roof and send a brush down while attaching bag to bottom of pipe at stove frame.

Thanks for you responses gentlemen.

I'd be really careful when you go to move the stove around so you don't tear your liner. A quality starter collar actually sandwiches the liner between two sleeves so when you insert the screws the two sleeves compress and hold the liner tightly in place. It also acts as a mini-chimney, directing smoke into the liner and eliminating the need for furnace cement / sealant. I'm surprised your starter collar fit so loosely. Are you sure you used the correct size?

Well - I purchased the stove and the flex pipe kit from the same dealer (not to say that is a foolproof solution!). The flex pipe kit was labeled as standard 4-inch pipe. Came with a "T" adapter, a collar, 25 feet of SS flex pipe, a cap to seal chimney and a top stack cap.

I had a lot of slop with the collar and "T" - both about 1/4 to 1/2 inch of play.

Thanks for your thoughts!