Any device to prevent high wind from blowing out the WH pilot light?

Jells

I have a Smith Proline tank WH that vents to a brick flue on the top floor of a building. Maybe 4-5 ft of 4" duct and the chimney rises maybe 3' above the roof. I used to have a Minitherm boiler there that would get whatever that safety sensor is called get tripped in high wind. I got rid of it more than a decade ago and replaced it with a tank (tiny apartment), and all was good. but last spring I changed the WH and now 2x this winter the tenant has called to say the WH is out.

Is there anything to be done? Any kind of flue damper than can be used with a simple atmospheric tank? Seems unlikely, but I'm asking.

mattmia2

the draft hood

mattmia2

if it was tripping the spill switch on the old boiler you have to figure out your vent issue.

Larry Weingarten

Hi, One approach is to increase the size of the standing pilot. The other is to understand what really happens when it's windy. You would want to be there, watch the pilot, feel around the draft hood, feel any breezes coming into the room, see if operating other equipment has an effect on the pilot… Diagnosing the problem could take some effort, but can be an interesting exercise in building science 🤠 Then there is figuring out the best way to fix the airflow. Could be as simple as a new vent cap… but I've had good luck increasing pilot size 😉

Yours, Larry

Jells

https://forum.heatinghelp.com/discussion/comment/1843509#Comment_1843509

Obviously it's a vent issue, If I could figure it out on my own I would not be asking here!

@Larry Weingarten unfortunately it is not my residence, it's a rental. I can't be living there waiting for a wind event!

Talk to me about chimney caps. There are none. This is an old school 4 stack chimney.

Jamie Hall

A chimney cap is dead simple. Just a flat metal plate or sometimes a cone, slightly larger than the diameter of the flue where it exits the chimney, held up on metal standoffs (on old chimneys it would have been a stone slab held up on a brick or two at each corner!) just far enough for the side openings to be greater than the flue area by a factor of two or so. Simple. Works wonders if the top of the chimney is too close to the roof, as yours likely is.

Jells

https://forum.heatinghelp.com/discussion/comment/1843566#Comment_1843566

Ok. How does it work to break whatever is going on? Is the problem a venturi effect when the wind blows across the flue top?

mattmia2

the wind blows down the vent. the cap deflects it around the vent

Jells

So here's the chimney. The one on the left is the culprit. I looked at the caps on the market and there's a flabbergasting variety. What would be most appropriate?

mattmia2

Have the mason you get to fix the cap put a masonry one on. That chimney has other serious issues.

Is that on the outside of the building so it is exposed to the cold of outside all the way up on 3 sides?

That building next to it that is much taller isn't helping matters.

Jamie Hall

https://forum.heatinghelp.com/discussion/comment/1843935#Comment_1843935

This. Masonry ap across all four flues.

Big Ed_4

With the unit up on the top floor venting into the top of the stone chimney and surrounded with other buildings.

I am thinking of two solutions ,

"H" type termination on the top of the chimney ….

Or a pilot relight kit …

Jells

https://forum.heatinghelp.com/discussion/comment/1843935#Comment_1843935

What exactly is a masonry cap and why can't I DIY it? When I google "masonry chimney cap" I get some variant of this. A few holes drilled in the bluestone top, some caulk and some Tapcons should mount it, no?

The chimney is flush with the outer wall of the building, interior on 3 sides, and the building next door is 50' away.

mattmia2

i mean i'm pretty sure the cap is just going to fall off on the roof if you try to drill a hole in it.

mattmia2

plus if you don't fix the cap you're going to be replacing the whole part of the chimney exposed to freezing temps

Jamie Hall

Well, thats the geometry anyway, though I'd put the cap lower. But I don't like the idea of drilling into that existing cap. I'd much rather see a nice slab of bluestone the size of the top of the chimney and perhaps an inch thick, supported on spacers, two brick high, at each corner and halfway along the sides… A competent mason using high quality grout can do that — and it won't crack anything (further than it is!) and I'd be rather surprised if it blew off…

Larry Weingarten

Hi, One more thing. I'm not seeing the 4" metal vent that the water heater is hooked up to. I'd want it brought all the way up to the top of the masonry or a bit higher so the water heater had a better chance of creating a natural draft. This would need to be under a hood so no rainwater could get in. Also, best if it's double walled, so it retains heat (and draft) better.

Yours, Larry

kcopp

STAR-KAP® ROOF VENT CAPS - Field Controls

PC7060

The cracked stone on chimney is allowing water into the brick and need to be addressed. Get a chimney mason to replace the stone with a masonry crown. They could also fit flue caps.

https://www.youtube.com/watch?v=jPRVVpMK-n4