87° or 90° Flue?

My boiler comes with an 87°flue elbow. Instructions clearly state that if no extensions are used a horizontal hole can be made ie 90°. But I still have an 87° flue elbow! Okay it is hardly close tolerance engineering but it does amount to 15mm off the horizontal difference. I can't work out if is supposed to be a 87/90 elbow or if I should just drill at 87°.

-- Mike W

Reply to
VisionSet
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If you drill it horizontally, then driving rain can and will go into the boiler.

Reply to
Ian Stirling

I was imagining it's a condensing boiler, in which case rain down the flue doesn't matter, but it should slope back into the boiler.

Reply to
Andrew Gabriel

Ah well, actually it is 87° at an up slope, in to outside!!!! The flue is held within a duct. The duct and the two are not concentric but actually this gives an even greater angle hence even more chance of rain going in!! So what? Its a condenser, water water every where - up and out as steam, trickle down and out through the condensate drain ... rain condensate whatever.

Ed can you confirm?

-- Mike W

Reply to
VisionSet

On Thu, 29 Jun 2006 23:31:24 +0100, VisionSet wrote (in article ):

So actually a 92-93 degree elbow.... This is normal for a condensing boiler.The purpose is so that the condensate flows back towards the boiler rather than dripping onto the ground outside. The mild acid would eventually etch your patio.....

Very little unless you are in a part of the country such as the east coast where it seems to rain horizontally.

It doesn't matter. There may be the odd drop of rain, but in comparison to the water that the boiler will produce, negligible.

Reply to
Andy Hall

On Fri, 30 Jun 2006 11:36:36 +0100, Shokka wrote (in article ):

That is not correct.

The flue should be angled so that the condensate runs back into the boiler and not out onto the ground. The mild acid would stain stone surfaces.

Reply to
Andy Hall

Actually condensing boiler flues are angled upwards (from the boiler) so that any condensation in the flue will run back into the boiler (and be collected with the rest) instead of dripping out of the flue terminal (and possibly corroding or staining whatever it drips onto).

Reply to
John Stumbles

Agreed. For a condensing boiler the flue should run downhill back to the boiler. As the OP says it's not high precision engineering. The flue components are nominally the right shape but can be secured into both correct and incorrect arrangements.

Reply to
Ed Sirett

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