2022/23 VC Owner thread

[xanadu1797]

VC Encore 2040
Started the season with the secondary air intake completely blocked off. Easily got cat light off temps and closed primary air back at 900F. Cat cruises between 1000 and 1300. Very rarely if ever stalls or goes above 1400.
I opened the secondary air which I understand feeds the cat as an experiment. Very difficult to get the cat above 600 and the griddle temp and cat temp are generally pretty close. Cat definitely not behaving like I thought it would with the secondary open. Was expecting a hotter, faster cat. Can someone help me understand what’s going on?

 

[arnermd]

Discovered something this morning, might want to check this on your stove.....

I noticed my doors were not closing quite right, I figured out the latch was hitting the air wash shelf. Door was sitting too low, so I adjusted the lower post on both doors to bring it up, just a touch, maybe an 1/8". Then I discovered my cam was frozen on the pin, rusted in place. Got it freed up and polished it up, works good now.

Had to adjust the cam length quite a bit to get it to clamp correctly. Checked it with paper in the gasket and several places, all seems good.

I do not think this was the cause of all my problems.... but we shall see.... One can only hope.

Happy New Years to all.

 

[arnermd]

VC Encore 2040
Started the season with the secondary air intake completely blocked off. Easily got cat light off temps and closed primary air back at 900F. Cat cruises between 1000 and 1300. Very rarely if ever stalls or goes above 1400.
I opened the secondary air which I understand feeds the cat as an experiment. Very difficult to get the cat above 600 and the griddle temp and cat temp are generally pretty close. Cat definitely not behaving like I thought it would with the secondary open. Was expecting a hotter, faster cat. Can someone help me understand what’s going on?

Couple thoughts:

• I ran with my secondary blocked for a good bit last year and I found a lot of creosote build up in the stack, a lot more than typical. Something to keep an eye out for. Some folks have had great success running with secondary completely blocked but I suspect you can get incomplete combustion if the secondary air is limited, hence the extra creosote. Even if your cat temps are good (and it sounds like they were) if there is not enough oxygen you will not get complete combustion. Look for smoke out the stack, no smoke is good.
• I have had burns where it was a struggle to get the cat up to temp. These seem to occur after I had a low fire, (maybe the catalyst was coated with creosote that needed to be burned off) or I was starting the stove from cold. Usually I can get through it if I get more heat in the stove, either increasing the air or just let the load coal up so I get a nice hot coal bed, then add some more fresh wood.
• I think opening the secondary air up will not give you a faster cat, it will be slower because you are diluting the hot primary combustion gas with cold air. it will take longer to heat up. But not much longer, with a good primary burn I can get the cat to light off in 10 - 15 min after I close the damper. Small fires take longer and sometimes the cat never lights off.
• But when it does light off you should get more heat out of it and less creosote (assuming you were limiting the oxygen before).
• I would suggest either a bigger fuel load or more air / longer in bypass to get the primary burn hotter/ bigger. Then throw in the cat and see what happens. Also try full primary air when you throw the bypass if you were not already.

 

[Eman85]

I keep reading posts where people are doing all kinds of modifications to the secondary air intake. I haven't read one that has any theory behind the operation of the secondary air or theory behind the modifications. I can't get any substantial info on exactly how the secondary air intake is supposed to perform or any temp specs on the controls for it. I've spoken to multiple VC dealers and been on the phone multiple times directly to VC. I've had them open multiple cases and email me case #'s over this. I would really like to understand the secondary air intake operation design.

 

[xanadu1797]

So if the cat is running between 500 and 800 degrees, is that enough for combustion? Because so far at those temps I’m not seeing a lot of smoke from the chimney

 

[Diabel]

So if the cat is running between 500 and 800 degrees, is that enough for combustion? Because so far at those temps I’m not seeing a lot of smoke from the chimney

The optimal cat temp should be 1200 to 1500 for the cleanest burn, regardless of the primary air setting.

 

[xanadu1797]

It’s pretty dramatic. When I take the block off the secondary air, the cat temp plummets even in the second half of a burn cycle with plenty of coals and fuel

 

[Eman85]

VC Encore 2040
Started the season with the secondary air intake completely blocked off. Easily got cat light off temps and closed primary air back at 900F. Cat cruises between 1000 and 1300. Very rarely if ever stalls or goes above 1400.
I opened the secondary air which I understand feeds the cat as an experiment. Very difficult to get the cat above 600 and the griddle temp and cat temp are generally pretty close. Cat definitely not behaving like I thought it would with the secondary open. Was expecting a hotter, faster cat. Can someone help me understand what’s going on?

On your stove how are you closing and opening secondary air? How is it made to work from the factory? Are you leaving or holding the secondary air completely while trying to burn?

 

[xanadu1797]

It’s wide open: not thermostatically controlled like some of the VCs, so I block it with a piece of ceramic gasket glued to tinfoil attached with a magnet

 

[Eman85]

It’s wide open: not thermostatically controlled like some of the VCs, so I block it with a piece of ceramic gasket glued to tinfoil attached with a magnet

So from the factory the secondary has no door or shutter, it's just a wide open hole that feed air into the refractory and the cat all of the time?
i believe @Woodsplitter67 has the same stove.

 

[Woodsplitter67]

So if the cat is running between 500 and 800 degrees, is that enough for combustion? Because so far at those temps I’m not seeing a lot of smoke from the chimney

Your cat will start to kick off at 600 degrees.. my stove runs well with cat temperatures of 800 to 1100 degrees.. if it goes past 1200 Im not stressing.. At 700 degrees its not a super clean burn on my stove

good question

 

[xanadu1797]

So from the factory the secondary has no door or shutter, it's just a wide open hole that feed air into the refractory and the cat all of the time?
i believe @Woodsplitter67 has the same stove.

Yeah, that’s correct. It’s a VC Encore 2040 2n1

 

[Woodsplitter67]

It’s wide open: not thermostatically controlled like some of the VCs, so I block it with a piece of ceramic gasket glued to tinfoil attached with a magnet

What stove are you running.. its not in your signature

 

[Woodsplitter67]

It’s pretty dramatic. When I take the block off the secondary air, the cat temp plummets even in the second half of a burn cycle with plenty of coals and fuel

Your cat will drop to the non active range with alot of coals.. Your offgassing is complete and there is nothing left to keep the catalyst going

 

[xanadu1797]

this is happening with an active fire

 

[xanadu1797]

The only thing I can surmise is maybe I have a less than optimal draft so by increasing the air to the stove I’m slowing the draft even more

 

[Woodsplitter67]

Yeah, that’s correct. It’s a VC Encore 2040 2n1

Your secondary air is coming in from the 8 little holes at the bottom of the refractory below the access plate..

i could be wrong but I doubt that is the issue.. If your cat temps are falling you may need to check the gasket between the refractory and the fireback plate.. the secondary air will leak directly into the cat chamber.. not mix with the smoke and combustion will drop

 

[Woodsplitter67]

this

 

[Woodsplitter67]

What is your draft like when this happens.. what is stovepipe temperature..

are you using a 6 or 8 inch and what is the length of said pipe

 

[Eman85]

It’s pretty dramatic. When I take the block off the secondary air, the cat temp plummets even in the second half of a burn cycle with plenty of coals and fuel

That's interesting. As I said I've been searching for info about secondary air. My secondary air is on a shutter with a thermostatic coil. With the stove cold the shutter is open slightly at one side as the shutter pivots to open. At 500*+ the shutter is closed. At approx 1550* the shutter reopens and when I've had this happen I have seen the cat temps drop until the shutter closes.

 

[xanadu1797]

I have the stove 2-3 hours into a burn cycle. Cat reads 1100. Damper closed, air all the way back. Griddle temp 450-500. I take off the secondary air port closure and the cat temp drops to 600

 

[xanadu1797]

Your secondary air is coming in from the 8 little holes at the bottom of the refractory below the access plate..

i could be wrong but I doubt that is the issue.. If your cat temps are falling you may need to check the gasket between the refractory and the fireback plate.. the secondary air will leak directly into the cat chamber.. not mix with the smoke and combustion will drop

This could be possible. I am using a custom metal gasket with a factory ceramic gasket. The stainless is slightly thicker but I thought I got everything tight.

 

[xanadu1797]

This could be possible. I am using a custom metal gasket with a factory ceramic gasket. The stainless is slightly thicker but I thought I got everything tight.

Custom being I had a weld shop use the old one as a template

 

[xanadu1797]

What is your draft like when this happens.. what is stovepipe temperature..

are you using a 6 or 8 inch and what is the length of said pipe

6” pipe, goes up about 25’

 

[Woodsplitter67]

6” pipe, goes up about 25’

what is the temperature of the stovepipe when this happens