Chimney cap for REDUCING draft in windy conditions?

[Andrew Robinson]

Hi there,

We heat our very well insulated home with a Blaze King Chinook 30.1. It works very well - even in relatively warm temperatures, once the catalytic element gets going, we turn the thermostat right down and the stove puts out just enough heat to keep the house comfortable. But for this to work, the stove has to be absolutely air-tight ... once the seal on the door starts leaking - even a little bit, the stove gets too hot. But I replaced the seal last year & it is working well these days.

Only small issue is that on windy days, the stove operates a bit too hot ... it seams to me that the wind blowing across the top of the chimney is creating extra draft, causing the stove to run hotter, even though the thermostatic air valve is closed. We have an outside combustion air vent that is well protected from the wind.

In looking for a better chimney cap - it appears that all caps are designed to use the wind to increase draft, not prevent it ... any suggestions?

Right now we have a basic 6" conical cap that covers the top & has a 1" metal band partially blocking the gap between the cone & the top of the chimney.

Andrew

 

[saydinli]

This is the one I have that my dealer put in because of high winds in my area.

It’s an ICC deluxe rain cap. I guess the idea is to reduce the amount of wind blowing across the cap inducing higher draft. It does come with 100% lifetime replacement warranty.

(broken link removed to http://icc-chimney.com/c/icc/img_db/chimney_product.img_hi/excel-EDRC_rain_caps.png)


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[Andrew Robinson]

This is the one I have that my dealer put in because of high winds in my area.

It’s an ICC deluxe rain cap. I guess the idea is to reduce the amount of wind blowing across the cap inducing higher draft. It does come with 100% lifetime replacement warranty.

(broken link removed to http://icc-chimney.com/c/icc/img_db/chimney_product.img_hi/excel-EDRC_rain_caps.png)

That looks very much like what I have now. Or perhaps even a bit less protected from the wind. Got ours at Canadian Tire.

http://www.canadiantire.ca/en/pdp/deluxe-rain-cap-0644274p.html

 

[yooper08]

You could put a damper plate inside the stove pipe above the stove. That way you can close it just on those days where draft seems to be strong.

 

[Andrew Robinson]

You could put a damper plate inside the stove pipe above the stove. That way you can close it just on those days where draft seems to be strong.

I was wondering about a damper too. There are down-sides such as what would happen if the wind died while I was not around to adjust the damper, making the chimney harder to clean and adding an additional potential leak where the damper is inserted into the chimney.

I'm hoping to find a chimney cap that blocks wind induced draft "automatically" ...

 

[electrathon]

Something as a possibility. The wind may not be causing suction on the top of the chimney, it may be causing pressure inside the house (this very much depends on many, many factors of the houses layout).

A damper is such an easy answer here. It seems to me that reducing draft at the top of the stack is a bad idea.

 

[yooper08]

Caps designed to block wind tend to increase draft as they're designed to prevent wind induced down drafts by creating an area of low pressure around the cap to essentially suck exhaust out. Blocking wind creates areas of high pressure on the windward side and low pressure on the leeward side, so I'm not certain a cap that blocks wind is your answer.