Blaze King Sirocco 20 Issue

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Dec 9, 2013
Free State of Idaho!
I have 2 BK Sirocco 20's. One is three years old and in the lower level of my home and the other on the main level I purchased brand new in October 2017. When I start a fire in the older stove, it appears to draft and light just fine like my new one. What I'm noticing is that the catalyst on my older stove is taking longer to come up to temp with the door closed and bypass open than my new stove. I've swapped the cat temp gauges thinking maybe the gauge was bad but that is not the case as the older gauge works just fine on my new stove.

On my older stove, the gauge will never rise past 50-60% into the active zone. The cat is glowing red but it just won't get any hotter than that before I'm ready to turn down the thermostat. It also does seem to me that it does not draft as well once I've closed the bypass. On my new stove the gauge will go to 80-90% into the active zone within 30-45 minutes of closing the bypass and then I turn down the thermostat.

I've inspected the catalyst on the new stove and compared to the old and they appear to be in good shape. no deposit buildup or peeling. I did also use a shop vac and a brush attachment to clean the face of the older catalyst and brushed the backside off as well. That did appear to help a little as before that the gauge was only going 40-50% into the active zone.

So any ideas? My gut tells me the catalyst is bad due to what I'm observing as a lower draft and lower max temp of the catalyst on the older stove once the bypass is closed.
So any ideas?

Are the stoves your primary source of heat? Many of the people running BK's as their primary heat source only get two to three years out of a cat.
You can try cleaning the cat with the vinegar bath method and see if that brings it back. Just make sure to have a new cat gasket on hand as they are not re-usable.
Another thing to check is the bypass gasket and the bypass door tension. If the gasket is bad or the door is loose, smoke will escape through the bypass instead of going through the cat.
They are primary heat source. But I only recently started burning the older stove with the temps getting low and baseboard heaters kicking on all the time. Electric bill went up over $200/month and I decided I'm not doing that. I'm aware of the gasket issue but hadn't heard about the vinegar bath. Just a soak in vinegar? for how long?

Bypass gasket also seems fine. I know it's not supposed to be as 'tight' as the door but I've closed the bypass and tried to push up on it and it has no give.
3 years of being the primary heater may have that cat near the end of its service life, which is around 12,000 hours. See if you can calculate about how many hours it's burned (I look at historical weather for my zip code to do this).

I think this has been covered, but I would check the bypass for proper seal, check the cat for being plugged (with a flashlight if possible on your stove; a cell phone camera with flash and some patience can work if the stove is cool snd you can't see through the cat with a flashlight). Make sure your draft is OK (check the cap, inspect the flue).

I would also go ahead and order a new cat and 2 gaskets. Even if you don't need the new cat right now, you will later. Try the vinegar bath as soon as the gaskets arrive.

Highbeam has a nice thread on cat bathing here.
A new catalyst will be hyper active for a while. Perhaps that’s the only difference? The new stoves cat is very responsive and runs on the high end of the active range. The older stove is well broke in, the cat gets very predictable and steady after some time.

If it’s running up at 50-60% and glowing red, it sure doesn’t sound like a bad cat to me.
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Webby, that is good info. I was not aware of that and don't recall ever seeing anything about break in and 'seasoned' cat differences. It does burn throughout the night. I'm just not turning it down as low as my new stove based on what appears to be visually 'under performing'. It does put out plenty of heat for sure.
So I pulled the cat on this stove a week ago and did the vinegar bath cleaning. Re-installed the cat with a new gasket and did a test burn. With the cat temp gauge at 50% into the active zone I went outside to view my chimney. My upstairs BK Sirocco was running as well. I could see visible smoke on the moderate to thick side coming from my downstairs BK flue and nothing but a heat wave from my upstairs flue.
I contacted Auto-Rain here in CDA where I purchased my BK last year and explained to them what I was seeing. They contacted BK and BK is sending out a new cat under warranty. Can't argue with that kind of customer service. I may have the new cat by the end of this week if not early next week. It will be nice to have the downstairs stove running like the other==c