Lined pipe or unlined flexible pipe in a brick chimney?

[risingfish]

I installed a used Avalon Newport about six years ago. Based on recommendations from one of the local pellet fireplace/spa stores, I purchased a 20' run of pellet stove rated (so they stated) flexible liner to run the pellet stove exhaust up our old brick chimney.

I had our chimney cleaned last week and the guy who did it stated that I should of run insulated pipe up the chimney instead of the flexible liner. He started going off about heat loss through the bricks, and some other stuff that sounded like a load of you know what. It seemed a stretch to think that enough heat to escape through the liner, into the air gap between the liner and bricks, and through the bricks themselves to affect combustion and exhaust in any way.

Is he just blowing smoke (figuratively)?

Thanks!

 

[railfanron]

I have an 18ft run of 4" uninsulated pipe up a class a rated pre fab sheet metal chimney. My stove has plenty of draft and the stove keeps the chimney almost squeaky clean. I only clean it every 6 tons or so. I see no need for an insulated chimney. If the stove was a natural draft appliance that would be a different story.
Ron

 

[mbhoakct76]

I have had 2 inserts, with both a flexible liner was recommended by manufacturer and used. no problems ever- brick chimney never needs a cleaning, we cleaned the ss liner after 7 or 8 years and barely a few spoons full of ash had built up. These are so efficient that barely any heat ever makes it to the chimney, its captured and blown into the room before it gets to the chimney. In both of my inserts- the air brought in from the room via vents at the bottom, so no air from the chimney is touched. I''m not sure if all are made that way. But that sounds like their opinion is based more on burning wood.

 

[risingfish]

It sound like the unlined SS flexible liner (3.5") running up my brick chimney is perfectly fine. That's what my gut was telling me, but it's nice to get confirmation. This is the first time in 6 years that I have had the chimney swept. There was a fair amount of build up, but the last two years I bought a brand of pellets that had a lot of water damage which isn't great for the combustion. I switched to a local brand of pellets this year and they're all dry as bone and burning great.

Thank you for the responses!

 

[alternativeheat]

I have a 32 ft run up an old brick chimney using 4" flex, never an issue, just get powdery ash out of it twice a year when I clean it. Where we bought the stove from they said they do 40ft installs with the same pipe.

Code for wood stoves is insulated liner but not pellet stoves in most places.