Mt. Vernon AE autoclean

[Harvey Schneider]

Over the past few years there have been a lot of people complaining that the MVAE's autoclean makes it difficult if not impossible for the stove to keep up the room temperature.
I recently finished building an electronic environment monitor and decided to test it by monitoring the temperature near the stove. I ran the monitor for about 14 hours from 5pm last night until 7:50 this morning.
I keep the MVAE burning on medium-high heat output and flame height set at mid scale. The temperature differential is set at one degree. I am not sure if Quadrafire means +- 1degree or 1degree total swing.
My results are:


The daytime temperature is set at 70 and the nighttime temperature is set at 65
You can see that the swing during the day was about 1.8 . Most people say they have the differential set to numbers about that large. I have no idea why the swing increased after midnight.
The temperature cycles of the room appear to be a little over an hour in duration. I have to assume that the autoclean cycles are buried in the thermostat cycles because the are not readily apparent. There appears to be an autoclean cycle at about 5:50 in the morning.
So, what is the problem people are complaining about with autoclean?

 

[Lake Girl]

Guess you'll have to stay up at night or start filming to determine what is happening. My guess on the midnight event was that it took that long to drop to new preset temp of 65. What time did you change the stat back to 70 in the morning? There are some interesting temp spikes (4:30)...

Were you running both stoves at the same time? Could be the stove in other folks' home doesn't have the additional heat support so the drop off and re-establishment of temp is more of a ramp-up than the stove can achieve; heat loss more rapid due to outside conditions, poor house insulation, higher draft potential... YMMV

 

[Harvey Schneider]

Guess you'll have to stay up at night or start filming to determine what is happening. My guess on the midnight event was that it took that long to drop to new preset temp of 65. What time did you change the stat back to 70 in the morning? There are some interesting temp spikes (4:30)...

Were you running both stoves at the same time? Could be the stove in other folks' home doesn't have the additional heat support so the drop off and re-establishment of temp is more of a ramp-up than the stove can achieve; heat loss more rapid due to outside conditions, poor house insulation, higher draft potential... YMMV

The PDVC is only run when I am in the workshop. it wasn't on.
Yes,it took 2.5 hours to cool down, but then the temperature swings are larger after that.

 

[JoeS]

I always liked the autoclean feature however I wish there was a way we could program it for longer cycles between cleanings!

 

[kappel15]

I was sitting by mine last nite in the basement, and checked the wall control when it went into auto-clean when it reached temp. I have my temp diff. set at 1 also. I lost 2.5 degrees before the stove started catching back up again, after restarting. Not bad as far as I am concerned. kap

 

[Harvey Schneider]

Some more data.
The dip in temperature late morning seems to coincide with when the stove was running with a nearly empty hopper.
I suspect that the auger doesn't feed as well without the weight of pellets above. That would result in less heat output. I remember adding a full bag of pellets some time in the late morning. With the insert, adding a full bag means it was just short of running on fines.



I guess I will go back to topping off the hopper every time I pass by. It just seemed more convenient to toss in a full bag at once and not have to deal with a partial bag sitting in front of the stove.

Measurements are taken every two minutes so I know that I didn't miss anything. I think that the little back porch on the declining side of each cycle is when the convection blower starts up again after an autoclean.

 

[kappel15]

Did you check the ashpan for a possible misfire?

 

[Harvey Schneider]

Did you check the ashpan for a possible misfire?

Good catch, There were some unburned pellets in the ash pan.

 

[Wilbur Feral]

I always liked the autoclean feature however I wish there was a way we could program it for longer cycles between cleanings!

Ditto. My only complaint with it. When burning ultra premium pellets I could go significantly longer. Still beats scraping, though!

HARVEY - Major geek cred for building the logger. Excellent work!

 

[chimneylinerjames]

The auto clean feature is changed by selecting the different pellet settings. Utility pellet will auto clean more often than hardwood. I believe if you set it on softwood, it will auto clean every 3 hrs.
Hardwood is set to auto clean every 2 hrs.
Utility is set to auto clean every 1.5 hrs.

Do not quote me on this, but I think those times are correct.

 

[Harvey Schneider]

The auto clean feature is changed by selecting the different pellet settings. Utility pellet will auto clean more often than hardwood. I believe if you set it on softwood, it will auto clean every 3 hrs.
Hardwood is set to auto clean every 2 hrs.
Utility is set to auto clean every 1.5 hrs.

Do not quote me on this, but I think those times are correct.

If the stove reaches the thermostat set temperature and the thermostat calls for a shutdown, the autoclean is done at that time. That is one justification for keeping the differential small. I don't notice the autocleans because they happen when the stove would have shut down anyway.

 

[kappel15]

The auto clean feature is changed by selecting the different pellet settings. Utility pellet will auto clean more often than hardwood. I believe if you set it on softwood, it will auto clean every 3 hrs.
Hardwood is set to auto clean every 2 hrs.
Utility is set to auto clean every 1.5 hrs.

Do not quote me on this, but I think those times are correct.

Close enough. 3.2- 2.1 - 1.2 And this is on high setting. kap

 

[john193]

Keep in mind though burning low quality pellets on softwood is a recipe for getting the autoclean jammed. And the autoclean is by no means a substitute for regular pot cleanings. There are plenty of clinkers it misses. I scrape mine weekly and get quite a bit of stuff off. Plus the autoclean doesn't clear the air holes on the wall off the burn pot facing the back.