your thoughts about my new raincap

[mary]

I have a freestanding iron stove with a chimney pipe passing through the ceiling. A few weeks ago I took the advice of my chimney sweep and had him install a new raincap. A "divergent nozzle raincap spark arrestor" to be precise, which cost rather a lot of money. As luck would have it within a few days of the installation we have experienced high winds and rain. Not the highest wind possible, but gusts up to 40 mph. Now, for the first time in the four years I've owned this property, I've got rainwater falling down the pipe into the stove. Not huge amounts of water, but I can hear it hitting the baffle inside the stove, and it's landing along with bits of flat carbonized material.

The installer tells me some rain getting in the pipe is to be expected on windy rainy days. I am troubled by this. I'm concerned my stove pipe will rust, as will the stove. There are no water stains in the stove that predate the new cap.

Would you share your thoughts with me about this. Is my concern reasonable, or is the chimney sweep correct? Thanks very much.

BTW, I'm delighted to have found your site. I'll read it with interest.
best regards, Mary

 

[webbie]

I have a freestanding iron stove with a chimney pipe passing through the ceiling. A few weeks ago I took the advice of my chimney sweep and had him install a new raincap. A "divergent nozzle raincap spark arrestor" to be precise, which cost rather a lot of money. As luck would have it within a few days of the installation we have experienced high winds and rain. Not the highest wind possible, but gusts up to 40 mph. Now, for the first time in the four years I've owned this property, I've got rainwater falling down the pipe into the stove. Not huge amounts of water, but I can hear it hitting the baffle inside the stove, and it's landing along with bits of flat carbonized material.

The installer tells me some rain getting in the pipe is to be expected on windy rainy days. I am troubled by this. I'm concerned my stove pipe will rust, as will the stove. There are no water stains in the stove that predate the new cap.

Would you share your thoughts with me about this. Is my concern reasonable, or is the chimney sweep correct? Thanks very much.

BTW, I'm delighted to have found your site. I'll read it with interest.
best regards, Mary

Well, first question was whether you had a wind or other problem which gave you reason to buy an expensive wind cap. If something is not broken, why fix it?

As Far as "divergent nozzle raincap spark arrestor", this is the first time in my 27 years in the business I have heard that term....do you know the brand name of this thing?

Now onto your question.....

I have never seen a chimney cap that did not allow some water in in SOME conditions. BUT, there is a big difference between some water coming into a masonry chimney- where it usually get;s defected or soaked up, and it coming in down a straight pipe into the stove.

If it didn't do it before, it should not do it now. Again, masonry chimneys are different since they can usually handle water.

Now, all that said, if you get 4 days a year when you hear some dripping inside the stove, that is no big deal. But if it happens quite often AND if the chimney cap is not fixing anything in particular....well, then it seems like you may have paid more for less!

So inquiring minds want to know - why did your sweep suggest this cap.

On a separate subject, Eliot Spitzer filed suit in NY State against some scamming sweeps.
http://tinyurl.com/acfeg/

The sweeps I dealt with over the years at my store were first class. But since I've been out of the retail biz, I've heard some real horror stories...

 

[mary]

The sweep reported the cap, or some part of the assembly up there, was rusting. That seemed reasonable to me. I've owned this property for 4 years, this is the third time he'd cleaned it for me, it was a rental before I bought it so who knows what was up there and in what condition.

I'm afraid I don't know the manufacturer, though I certainly will find out tomorrow. My invoice says "6" round stainless steel." I'll find out as well what a divergent nozzle might be.

I gather from your reply that rain water regularly in the pipe and stove is *not* a good thing.

Thanks for your reply. I'll do my homework and report back.

best regards, Mary

 

[elkimmeg]

Mary the more infirmation you reveal the more one has to wonder To the best of my knowledge Stainless Steel does not rust. and I can't see haw a cap would prevent stainless steel from rusting. Isn't that the purpose of putting the cap on to prevent moisture from getting in? I too would like to hear about the brand cap in fact the cost of labor for the services rendered.

 

[webbie]

[quote author="elkimmeg" date="1136052021"]Mary the more infirmation you reveal the more one has to wonder To the best of my knowledge Stainless Steel does not rust. and I can't see haw a cap would prevent stainless steel from rusting[/quote

I've definitely seen class A chimney tops which needed to be replaced. They are often stamped out of very light gauge ss and also this is where any acids and consensation tend to form. So it is surely possible that in 10 years plus one would degrade. Although we do not use the word "rust", that is actually what it is. Stainless can pit, wear through, etc. etc. In fact, I have some stainless table ware that has quite a few "pits" on it.

As with other posts, I am not trying to hang the sweep here, although the "divergent nozzle thing" sure sounds like a pitch. If the cap was not actually eaten away, some discolor and pitting would not be enough reason (in my book) to replace it - but, then again, I use stuff until it is completlely broken!

There is another issue here. Class A Chimney comes in two types, PACKED and AIR-COOLED. If the chimney is packed, then any generic cap can probably be used safely.

If the chimney is air-cooled, then a certain type of cap which still allows for the cooling air to circulate must be used.

Again, not second guessing the sweep - he is the only one that was on the job. Just giving you information that is somewhat generic about these things.

 

[webbie]

Mary, I'm a cynic. I'd guess that the guy ripped you off.



"Although we do not use the word “rust”, that is actually what it is."

Rust is iron oxide. The chromium in SS prevents the iron in the SS from combining with the O2 in the air in the presence of a water catalst. No?

Well, I suppose we could more accurately call it:
pitting
discoloring
pin holes
corrosion

and a number of other names. But for purposes of the normal consumer understanding this, corrosion is probably the simplest term.

from the web:
Metal Polishing Myths, Half Truths and Lies
20. Stainless Steel doesn't rust, oxidise or stain

A complete misconception is that stainless steel is stain proof. It is not. It merely stains less.

Austinitic stainless steel won't tarnish, stain or discolour easily, but martinsitic will, and it all will if you overheat it or allow it to come into contact with steel.

All stainless also takes on bleed marks and stains from other metals easily .

 

[roac]

When researching bbq grills I learned that the grills are made from two different grades of stainless steel. The easiest way to tell high vs. low quality stainless is to use a magnet. If the magnet holds to the stainless then it is high grade. The low grade stuff will discolor more and could eventually fail with the high heat of a grill, I assume the same is true for chimney caps.

 

[joshuaviktor]

Didn't do too much work with Stainless when I blacksmithed, didn't have much interest in Chromium poisoning. (gee, what a wimp I am! ) Anyway, the magnet test is the best, as Craig said. Historical bit of trivia. During WWII, when they had the scrap metal drives, they hired thousands of blacksmiths to test scrap metal. Blacksmith can hold to a grinder, different colors of sparks tell him what grade of steel it is. Whiter the spark, higher carbon the steel. Just thought you'd get a kick out of it.

P.S. Do not, under any circumstances, try to forge, or get red-hot or greater, stainless steel, or galvanized. Or at least wear a fairly serious grade respirator. Zinc is good in a vitamin, not plating your lungs. And chromium is great to lose wieght with (chromium picolinate), but not good in the bloodstream.

Your friendly neighborhood, half crocked blacksmith,

Joshua

 

[tradergordo]

I was about to ask a very similar question to the original poster's. I have no experience with this stuff, just installed a new supervent chimney within the last week, flue is not connected yet. Last night we got a VERY heavy rain so I thought it was the perfect opportunity to check for leaks. There were noleaks from the sides of the chimney or the flashing, but SOME water was coming straight down the stainless steel pipe. I have this Superpro 6" Deluxe Rain Cap:
<img src=http://www.hartshearth.com/productcart/pc/catalog/77655-sp-class-a-cap-md.jpg>

It definitely was not direct rainfall, but smaller drops. I'm assuming the rain was hitting the top, and some was bouncing off the inside wall and then down the pipe.

I was also wondering if this is normal?
Is there a better rain cap that anyone here can recommend? This seems like it would be enough water to rust the cast iron stove out over time. I was even wondering if I should remove the rain cap in the off season (non-heating season) and just put a big stainless steel bucket over the chimney top?

 

[begreen]

I've had a Metalbestos 6T-CT cap for years. Rain in the pipe happens only on rare occasions, and then only a little.

 

[Nic36]

Gonna resurrect a very old thread here, mostly due to TraderGordo's post. I recently installed a Supervent chimney with the Deluxe Rain Cap. I think it is identical to the Superpro cap in looks. Since I have not installed a stove as of yet, I can shine a flashlight up the chimney during rain storms. I've noticed some drops of water entering the chimney at the rain cap. It looks like rain is hitting the cap and some droplets ricochet off parts of the cap into the chimney. This must be the case since I see several drops on the inside top of the cap. Some is also blowing in too. Some drops make it all the way down to the bottom of the chimney where they land on the floor. Most of the drops that get in never make it all the way down and just cling to the wall of the chimney. After a while, the natural draft up the chimney will evaporate them.

How much water is too much? I have consistently seen some water in the chimney every time it rains. Is this normal? Should I look into getting another cap? If you read this TraderGordo, did you change caps?

And more seriously, I also have an issue of water dripping out one spot of the ceiling support from the outside lip of the stove pipe adapter. I've already been in the attic twice and made sure it was not leaking around the flashing and down the chimney that way. Although, I kinda wish it was since that would be an easy fix. I think water must be entering a chimney pipe seam and getting inside the chimney insulation where it makes it all the way down to the stove pipe adapter. It is dripping out the adaptor very close to the seam off the chimney pipe. I guess I can silicone the chimney seams on the outside of the house and see what happens during the next rain.