Cannot line chimney

ChrisJ

Hi,



I've run into a problem installing the new boiler and I'm just curious how often this happends.  My chimney is too small to fit a 5.5" liner or even a 5" liner ergo I cannot use the chimney for my 150K btu input boiler. The chimney is big  enough in SPOTS but others are too close so the liner cannot fit.   Because of this there is a pretty good chance I'm going to just have an A vent ran up the side of the house.



This is going to cause me to move my boiler, steam mains, condensate returns and over all is just a big pain in my butt.



I'm sorry as I am just upset / annoyed / confused and just need to "vent" ;).

Have many people run into this same problem when doing a project like this?  I am alone?

lchmb

tiles

Is it that some of the old tiles in the chimney are falling or is this a very small chimney? Most in my area are 2x to large...never had one that small on an older house...Have you had a chimney man into look at your problem? Think it may be cheaper to have that existing chimney repaired/replaced over relocating a boiler and redoing steam mains..

Charlie from wmass

Burnham makes

a side wall vented boiler for steam. Removing the chimney and running B vent for gas or all fuel for oil may also be an option. Oil boilers can also be side wall vented.

ChrisJ

small chimney

My chimney man is the one that tried to line it. It is I think he said 7x7 or 8x8 tile above the offset in the attic and then it goes to rectangular unlined (no tiles) and its something like 4x9 inside.



The chimney place gave me two quotes and I was surprised to find it was the same price to tear the chimney down and run B vent without repairing damage to the walls as it is for them to run "A" vent up the side of the house. I have to assume that stainless pipe is quite expensive?



I liked that they gave me a quote to repair wall damage separately as I am more then happy to do the work my self.



As far as power venting I already bought a WM EG-45 assuming this chimney could be lined. Getting that block down my winder stairs was hard enough, its not coming back out .

Techman

Chimney

Gas or oil? Is the chimney inside of the house? The old boiler vented into this chimney w/ no problems?

ChrisJ

Hi Techman

The old boiler was a 91,000 btu input oil fired boiler.  New boiler is 150K btu input gas.  Old boiler was grossly undersized which resulted in a very unevenly heated house as this is a steam system.

At any rate, no the previous boiler didn't vent very well.  I was never able to get any draft out of the chimney and the house STUNK like diesel and soot when we bought it. 



I just don't understand how this chimney is so small or how it worked with a coal burner originally?  Chimney was originally unlined.

Techman

Chimney

Re-doing everything is crazy. Using a vent assist fan , power assist, is out of the question ? If so, then ripping out the existing chimney might be a possibility. As far as I know ,single wall " A " vent is not for outdoor/cold applications . If used double wall "B " vent might have to be enclosed,depending. Can you open a couple of holes in the walls to see this "square to rectangle " piece? If you're doing this once then stainless might be the way to go.

kcopp

Thinking out....

of the box.... Is it possible to drop a 4" liner and then put of of the fan assisted power vent on top of the chimney? that usually allows you to use a smaller vent for the flue....

http://www.chimneyfans.com/contents.aspx?page=RS

ChrisJ

fan

Thank you for your responses. I had wondered if someone made a fan assist for something like this and am glad to see there actually is one.  A 4 inch would fit though it would still be really tight in a few spots.



However after thinking everything over and considering the conidtion of the brick chimney is far from perfect and could even be dangerous in the future we are going ahead with tearing it down.  I'm sure it will also make the place easier to sell in the future if we ever want to.







Its far from the easiest route at this point but is probably the best one overall.

Tim McElwain

The chimney probably worked in the

past because of a high flue gas temperature which was able to overcome the lack of size. Draft is created by delta T (temperature difference) and the height of the chimney. If it is an inside chimney it would have very low flue loss due to cooling off.



I have seen hundreds if not thousands of undersized chimneys in my career. They should not have been working but they were and showed no evidence of any time they did not work. The older appliances had much higher flue losses which helped to overcome the internal dimensions to some degree.



The standards for the old stuff was between 4,500 to 6,500 BTU's per square inch.

Tim McElwain

Keep in mind if you use

a power venter at the top of the chimney it must be interlocked with all the equipment that goes into the vent so that if the venter is not working the equipment will not come on.

Techman

Also,keep in mind ,

some brave soul, w/ tools has to Hop/Skip/Jump /Crawl/Dance his way out to that chimney and back several times on any service call relating to that thing WAY OUT THERE ,alot of times!