Removing vent pipe for chimney inspection?


Old 12-03-08, 02:52 PM
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Removing vent pipe for chimney inspection?

Hi folks Ė

I know this is elementary stuff for the folks on this forum but I looked and looked everywhere - but canít find the details on how to remove/install a boiler vent pipe (or is it flue pipe?) from the chimney wall. I remember the service guy removed it 2 years ago to inspect the chimney at which time there was some shale in the bottom of the chimney. But I canít picture now what he did in terms of vent pipe removal.

Iíd like to look for myself now. I realize you need real expertise and a special camera to do a proper chimney inspection job, but I figure it would be worth a look for myself, from down the chimney top and up from the bottom , to see if it is completely obvious to even me that the chimney needs relining. I guess my lining is clay tile(?) but a replacement would be stainless steel? I realize it must be very important to get the pipe back correctly otherwise you could get some toxic fumes in the home- I think. (But I donít see why a DIYíer couldnít do it right as long as he was very careful.)

I would also like to clean the vent pipe. (I read somewhere that it should be called the vent pipe and not the flue pipe. Is that correct? Seems like the terms are used interchangeably all the time.) I replaced nozzle, oil filter, cleaned pump strainer, removed motor and cleaned air guide, cleaned firetubes, etc. Ė but didnít clean the vent pipe. Are you supposed to clean the vent pipe periodically?

If I understand there should be a thimble(?) in the chimney and thatís where the pipe connects. It seems to me you would have to disconnect the entire pipe Ė right from smokebox connection (is that the correct term?) to the chimney wall connection. Otherwise I donít see how you could just disconnect the chimney end (at the thimble?) and be able to move anything out of the way?

Iíve included 2 pictures (hopefully). Is that round thing on the chimney wall the thimble? Itís covered with stuff (furnace cement I presume?). Would I just chip that cement away and then see some kind of exposed connection (screws?). I have furnace cement.

Any advice would be greatly appreciated!
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Old 12-03-08, 03:07 PM
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I am a mason if your chimney is lined with an 8x8 flue tile or an 8x12 if there was shale it might be damaged at the top, what are you exhausting out your your chimney (furnace,watertank,fireplace) what ever it is the pipe should be going in the chimney somewhere near the furnace turn off the appliance then unscrew the pipe remove from appliance, remove from wall its the only way.
Old 12-03-08, 03:32 PM
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This is an easy one.

Move boiler 4" away from they chimney, then.............

Just kidding

I think the thimble may be clay pipe installed by the mason, or it is sheetmetal that is over sized and should be installed in a different manner after removal and inspection,

I would CAREFULLY break away the furnace cement close to the smoke pipe, working outward until you find out what the thimble is made of. If it is clay, be careful not to break it.
After the chimney side is loose, you may want to disconnect at the boiler breaching, and check for screws needing removal first.

You can replace exactly as it was or after you find out what is there, we can help you install it the best way with hopefully no cement removal again.
Old 12-03-08, 04:32 PM
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Thanks guys!

My heart stopped when I saw move boiler 4Ē away Ö although I did move a 450 lb. fireplace insert myself (my sister swears thatís why I got a hernia). I make these things I like to call Egyptian ramps like they used for the pyramids . But I think moving the boiler might be a tad bit harder!

lakings11 I believe it might be an 8x8 flue tile. I seem to remember that I measured it one time when I was putting a top damper on another flue (?) (the fireplace flue(?) ) and I think the one for the boiler was smaller and was 8x8 . If I remember it was that terra cotta color. (Please forgive if I use the wrong terms). I didnít want to go up and walk on the roof again now to check size and type unless I was really ready to do some work. But Iím sure itís flue tile. I donít remember it looking damaged then Ė although I wonder if I would have noticed when I measured? (I guess I would have?)

Iím exhausting only the oil-fired boiler out of that chimney and the boiler is only a few feet from the chimney wall.

I believe you guys answered my question. I can certainly see the screws holding the pipe to the appliance Ė which if I get it, in the case of this appliance, itís called the boiler breaching . So no problem there.

I will work on the wall side carefully as you say plumingods finding what the thimble is made of and be very careful if itís clay. That would be great if you guys could advise how to do the best installation. Never even occurred to me an install might be possible without future cement removal.

When I get to that point Iíll make another post.

Thanks a lot for your time and expertise guys!
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