Proper chimney cap install for new gas insert

[dave11]

I have a brand new gas insert that came with two sections of round 3" liner and a new chimney cap, but as you can see in the attached photo, the base of the new cap is a piece of flat metal, I assume to allow "one size fits all." The install instructions with the cap/liner simply say "Install cap to top of chimney," and give no other explanation. I've queried the company but haven't heard back from them yet, and wanted to get started. Does it seem right to assume that the corners of the base of the cap are cut out, as squares, and the four sides folded down over the top of the chimney tile, then screwed into place?

Just want to make sure I'm not overlooking something obvious, before I cut.

As an aside, the install manual does not address or show a drip leg in their diagram of the gas piping. Is that an oversight on their part, or is it not necessary to put a drip leg on gas inserts?

Thanks.

 

[R&D Guy]

Dave, not sure of the mfg of your pipe, but here's a diagram on Simpson Duravent's webpage that might be helpful.

http://www.duravent.com/?page=instruct/dvent/952/L952pg3.php

 

[dave11]

Thanks R&D;Guy. That link has way more detail than the install manual. Now it makes more sense.

Can anyone comment though on whether a drip leg is a good idea on a gas insert?

Thanks.

 

[R&D Guy]

Sure - I find the info that comes with the pipe to be totally inadequate, but I think they do that for liability reasons. Is this for condensation inside the pipe, or in case rain water leaks down the outside of the pipe?

 

[dave11]

I guess I should have been more specific about the drip leg. I mean on the gas line itself, after entering the firebox, but before entering the insert.

Most gas appliances are meant to have them, but the install manual doesn't mention it.

 

[dave11]

After reviewing the Duravent install, which appears to have the same flat base as my unit does, I'm still a little confused. It appears both products require a flat surface at the top of the chimney, where the chimney tiles must be flush to the top of the chimney. But don't most chimneys have tiles that stick up above the brick and mortar? Mine does, as do all my neighbours.

Am I missing something here?

 

[theheatelement]

I'm assuming you bought an Empire Comfort fireplace and that is the system you got with it... that flashing plate is meant to mount on top of your chimney and you are to trim the side with a pair of snips as every chimney is different... if you have any questions feel free to let me know and I can help you out as I work with ECS on their solutions.

 

[dave11]

Hi Magnaflex. thanks for the help. Yes, it is an Empire dual vent. The install manual actually says only to "Install terminal cap to top of chimney," and says nothing more, at least as far that part of the install goes. My guess was, as I mentioned in my first post, to cut in squares at the four corners of the base plate, and then fold down the four sides as flaps. But should those flaps be fastened to the tiles, or folded down further and secured to the mortar?

Thanks again.

 

[dave11]

Actually Magnaflex, as I reread your last post, i'm thinking you mean to trim the sides of the base plate so that it does not extend past the edges of the clay tile riser? Wouldn't that leave only a narrow area of contact between the base plate and the top of the chimney?

 

[theheatelement]

Well the brick is what 3 inches round all the way around so that should suffice in a mounting area, I would measure and then snip the metal to size, silicone the top of the brick and lay your flashing on it and then fasten the flashing with some concrete screws, that should suffice.

Actually Magnaflex, as I reread your last post, i'm thinking you mean to trim the sides of the base plate so that it does not extend past the edges of the clay tile riser? Wouldn't that leave only a narrow area of contact between the base plate and the top of the chimney?

 

[dave11]

Sorry to be so dense, but I'm still not quite following what you're saying. My chimney has the typical mortar crown, with the last flue tile rising a couple inches above the mortar. I'm not sure what you mean by three inches of brick for attachment.

I'm still not quite sure where the base plate is supposed to be attached to the chimney. It's central opening is only 4x8 inches, so it can't be lowered over the tiles to attach flush to the mortar. Is the base plate supposed to be placed on top of the flue tile, then trimmed flush with the edges?

 

[PaulRicklefs]

I guess I should have been more specific about the drip leg. I mean on the gas line itself, after entering the firebox, but before entering the insert.

Most gas appliances are meant to have them, but the install manual doesn't mention it.

Generally small appliances like cookstoves and decorative appliances aren't required to have them. If there is room I always put them on everything. Just remember that you can't put them on if it will end up in a concealed area. (That's the trick)