How Long to Bypass on Reload

[Garrin]

Howdy All,

First season running a Bk Princess Insert (or woodstove at all, for that matter).

I reached out to BK about this but haven't heard back.

On a hot reload, how long should I leave the cat bypassed? I've heard mixed information on here.

Some are in favor of leaving the bypass open for 5-10 to let moisture cook off before engaging the cat- which supposedly means longer cat life as you're not shocking it with water vapor.

Others say that you're good to go as soon as you've got the loading door closed, so long as the car is in the active range.

Any definitive answer on this one?

Thanks all.

 

[NHWS]

The stock cat gauge is slow. It tells you the cat temp several minutes ago. I've heard estimates between 5 and 10 minutes. If you just closed the door after a hot reload, you don't know the *current* state of the cat.

In my Copious Free Time(tm), I'm looking into a digital cat gauge to get quicker info. Check the VC Owners threads - there are some discussions about it for VC stoves. AFAIK the very experienced BK owners here are not using digital cat gauges. Not sure why not.

What I've been doing instead is using a digital flue temp gauge as a proxy for the state of the cat. Once the flue gas gets to 600 dF, I close the bypass. Sometimes that's just a few minutes, sometimes it takes 10+ minutes, depending on the coal bed and the kind of reload. The flue gas usually drops 50 to 75 dF when the bypass is closed, and then starts slowly going back up.

I leave the air all the way up for 15 minutes after that to reduce the remaining MC of the wood, then start slowing it down.

Not sure if what I'm doing is right, but there are at least a few other people here doing similar things.

 

[DonTee]

On my PE32 Princess I close the bypass after the flue temp is 600-700 degrees. That’s assuming the cat is in the active zone by then. If it’s not, I turn down the stove temp knob a little to keep the temp under 700 until the cat is in the active zone, then I close the bypass and turn the temp back to max.

After the bypass is closed I let the temp get back up to 600-700 before turning down the temp to my desired setting.

 

[kennyp2339]

Princess owner here, I have a wood stack next to my stove, so the wood is usually room temp, I open by-pass load and close the by-pass all in one shot, if the wood is coming directly from outside and cold, I'll leave the by-pass open for like 5 min, my splits are never wet or snow covered since its stored in a woodshed or inside on the rack.

 

[Dieselhead]

Same as Kenny, as long as temp gage is in active zone.

 

[Highbeam]

Kinda splitting hairs. Doesn’t really matter? Assuming the cat meter is active and the new dry wood ignites quickly as it should, send it!

 

[Garrin]

Thanks all.

Based on replies, I probably should have tried to install a flue temp probe when I installed the unit, but that's alright.

From what I have gathered generally, so long as I've got dry wood and don't keep the bypass open indefinitely or open the loading door without opening the bypass, I should be fine.

My big "wonder" is whether those little procedural differences can affect cat lifespan as I've heard some folks claim.

I suppose another thread of "how to maximize cat life" might be a better question.

Again, thanks for the replies!

 

[Tron]

I probably should have tried to install a flue temp probe when I installed the unit, but that's alright.

You still can. All you need is to drill a 1/4" hole into the flue about 2' above the stovetop and insert a Condar or something.

To your initial question, when the cat is still in active range, I usually leave the bypass open until I see that all splits have caught fire and it's raging in there. With coals left, that usually takes 5 Minutes, tops. Then I close the bypass and turn down the thermostat in one go.

 

[NHWS]

I've found that leaving the air full open for around 15 minutes reduces smoke from the chimney.

 

[Garrin]

You still can. All you need is to drill a 1/4" hole into the flue about 2' above the stovetop and insert a Condar or something.

To your initial question, when the cat is still in active range, I usually leave the bypass open until I see that all splits have caught fire and it's raging in there. With coals left, that usually takes 5 Minutes, tops. Then I close the bypass and turn down the thermostat in one go.

I didn't realize installing a probe is so easy. I imagine with the negative pressure there's no need to seal it or anything?

 

[DonTee]

I didn’t seal mine with anything. I remove it whenever I clean the stove pipe.

 

[Garrin]

I've got the princess insert. Other than checking it being a bit annoying, does that present any other problems with the flue probe?