How much is too much combustion air?

jumpers

I think you would see pellets flying out of the burn pot along with lots of hot ash (sparks)

Too much air will burn up the pellets probably faster than needed. Most Harmans automatically control the fuel air ratio.

Most Harmans automatically control the fuel air ratio.

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Really? Tell me how this is done, and do I have this feature on my XXV?

Now I'm confused...

I have a lot of hot ash flying around in the stove, but my glass has been clouding up pretty quick too. Do I have too much air, or not enough?

cantman said:

Most Harmans automatically control the fuel air ratio.

Click to expand...

Really? Tell me how this is done, and do I have this feature on my XXV?

Click to expand...

There is no damper to set the air mix. You simply follow the instructions to set your maximum feed limit. The stove handle adjusting the feeder, the blowers, and the ignitor. All in the electronics.

Of course it is not a perfect world. You do need to keep things clean, and you may need to tweak the feed limit knob if you change pellet brands.

codebum said:

cantman said:

Most Harmans automatically control the fuel air ratio.

Click to expand...

Really? Tell me how this is done, and do I have this feature on my XXV?

Click to expand...

There is no damper to set the air mix. You simply follow the instructions to set your maximum feed limit. The stove handle adjusting the feeder, the blowers, and the ignitor. All in the electronics.

Of course it is not a perfect world. You do need to keep things clean, and you may need to tweak the feed limit knob if you change pellet brands.

Click to expand...

Does the combustion blower on the XXV just switch between the regular draft (full speed?) and the low burn speed, or is the combustion blower fully variable over its full range and varies the air mix by the control board module?

I've been playing around with the air on my new Englander 25 PDVC. What I have found is I can get higher temp. readings on the stove with a little less air, but the glass gets dirtier. You would think that higher temps. would = cleaner burn, not so in my case. I'll just clean the glass more often.

Does the combustion blower on the XXV just switch between the regular draft (full speed?) and the low burn speed, or is the combustion blower fully variable over its full range and varies the air mix by the control board module?

Click to expand...

I believe that it switches between low draft and high draft speeds. It runs at full voltage during high draft (normal burning) and slows down to low-draft during a low burn and during startup it is in low draft. The only variable adjustment is the low draft adjustment which on the XXV is factory
set at a mid-point adjustment and in most cases will not need any adjustments. The adjust ment only affects the low draft.

cantman said:

codebum said:

cantman said:

Most Harmans automatically control the fuel air ratio.

Click to expand...

Really? Tell me how this is done, and do I have this feature on my XXV?

Click to expand...

There is no damper to set the air mix. You simply follow the instructions to set your maximum feed limit. The stove handle adjusting the feeder, the blowers, and the ignitor. All in the electronics.

Of course it is not a perfect world. You do need to keep things clean, and you may need to tweak the feed limit knob if you change pellet brands.

Click to expand...

Does the combustion blower on the XXV just switch between the regular draft (full speed?) and the low burn speed, or is the combustion blower fully variable over its full range and varies the air mix by the control board module?

Click to expand...

I believe that it switches between low draft and high draft speeds. It runs at full voltage during high draft (normal burning) and slows down to low-draft during a low burn and during startup it is in low draft. The only variable adjustment is the low draft adjustment which on the XXV is factory
set at a mid-point adjustment and in most cases will not need any adjustments. The adjust ment only affects the low draft.

Click to expand...

So in reality, the only air/fuel "automatic" adjustment that the XXV controls is when the unit goes into "low draft" mode and "high draft" mode. (2 modes for combustion air control, not infinitely variable)

So in reality, the only air/fuel “automatic” adjustment that the XXV controls is when the unit goes into “low draft” mode and “high draft” mode. (2 modes for combustion air control, not infinitely variable)

Click to expand...

Correct...that is my understanding of it. If anyone knows differently, I hope they will correct me. I don't worry about it too much. It's a good idea to understand how it all works, so that you understand why your stove reacts in certain ways, but for the most part (other than when I burned different brands of pellets) I set mine and then don't have to change anything from that point on. Just clean it when it needs it.

CZARCAR said:

BJN644 said:

I've been playing around with the air on my new Englander 25 PDVC. What I have found is I can get higher temp. readings on the stove with a little less air, but the glass gets dirtier. You would think that higher temps. would = cleaner burn, not so in my case. I'll just clean the glass more often.

Click to expand...

are u cutting down combustion air?

Click to expand...

Yes, combustion air.

Orange Crush CJ-7 said:

I know a sooty burn and lazy flame result from not enough combustion air, but how about too much? Is there such a thing? what are the symptoms/how would I know If I have too much combustion air? If I have too much combustion air, will I be pumping the heated air out of the firepot too quickly before it can effectively transfer the heat to the heat exchangers and make hotter/more wasteful flue temps?

Click to expand...

Hi Justin, like you I have an Englander 25-PDVC that I installed last year. My experience so far is that it varies with which pellets you're using. With some hardwood ones I have to up the low air burn button to 6 or 7 and the low feed rate the same. I usually run my stove at 6-6-1 settings. I've burned Blazers where I had the low air and low feed on 5 with no problems but usually have them set on 6 with other brands.
I think each stove installation varies with the flue pipe installation also. I have a 6' run up the inside wall, 2' out, and 3' up the side of my house with 3 " Duravent pipe along with 3 90 degree fittings and a cap, so I have a little more air to push than most people.
The fire inside my stove is a nice bright yellow and the flames are strong and vertical almost hitting the top of the inside of the stove. My blower temps vary with the pellets used but the Blazers averaged around 250+ degrees and some like Fireside and other less than great brands were only 180-190 degrees. My vent pipe temps inside the house average 130-150 degrees which is why I decided to make a 6 ' vertical run up from the stove and then outside, I didn't want Al Gore getting ticked at me and I figured I'd like the extra heat inside the house.
Some brands of pellets with blacken the door glass on my stove within hours and others it will take a day or two. So again, it seems to vary with the brand of pellets you use. I clean my stove of ash and the glass daily and every 2-3 days vacuum it out thoroughly. With Blazers I can go almost a week without a good cleaning.
I have a " T " fitting outside as one of the 90 degree fittings and I empty it every 2-3 weeks and I've never had more than 1/4 cup of fine ash in it. I monitor the flue pipe coming out of my stove and if I think it's getting too hot I back the low air burn down a notch. So I think each stove has to be tinkered with to get the optimum temps out of whatever brand of pellets your using.----Lorne.

to much air will tend to make most pellet stoves look like a tourch. can cause warpage and shut downs.

I think I'm getting really good draft too, I'm running my stove with 6" single wall pipe into an 18' masonry chimney. I did have an Englander tech walk me through programing my stove to run on high fire mode because I didn't feel it was putting out enough heat. I'm now getting over 500 deg. on the outside of the stove using an infared thermometer.