Kuuma VF100 arrived

[Highbeam]

I've been keeping an eye on this thread. A big thank you to our current Kuuma owners for always trying to be so helpful on any type of questions or issues. I really appreciate you doing this! For anyone with questions or concerns please feel free to call or e-mail us directly, but sometimes it's easier to use this awesome forum. When contacting us it's great to first e-mail some pictures of your set-up before calling my dad directly at the shop the next day. He's much more detailed over the phone, especially if he has seen your set-up. He does only goes over e-mail once a day with my mom and it's usually later at night. Rest assured that we will get you taken care of because we want you to have a great customer experience. Please make sure that you follow the installation instruction in the owners manual, which can also be found on our website. The majority of issues we have ever had come from incorrect installation. From time to time we do receive defective parts from our suppliers, and if that's the issue it's very easy for us to get you out a replacement. My dad does a good test of a couple items before the furnace is shipped, but this can't catch everything.

To summarize We spend a ton of time helping people with questions. I couldn't even tell you how many e-mail chains we get going with some owners to ensure proper operation. So any that are solved here it's really appreciated!

And it adds value to your product when your company has representatives visiting these forums as well.

 

[Monaco]

I've been keeping an eye on this thread. A big thank you to our current Kuuma owners for always trying to be so helpful on any type of questions or issues. I really appreciate you doing this! For anyone with questions or concerns please feel free to call or e-mail us directly, but sometimes it's easier to use this awesome forum. When contacting us it's great to first e-mail some pictures of your set-up before calling my dad directly at the shop the next day. He's much more detailed over the phone, especially if he has seen your set-up. He does only goes over e-mail once a day with my mom and it's usually later at night. Rest assured that we will get you taken care of because we want you to have a great customer experience. Please make sure that you follow the installation instruction in the owners manual, which can also be found on our website. The majority of issues we have ever had come from incorrect installation. From time to time we do receive defective parts from our suppliers, and if that's the issue it's very easy for us to get you out a replacement. My dad does a good test of a couple items before the furnace is shipped, but this can't catch everything.

To summarize We spend a ton of time helping people with questions. I couldn't even tell you how many e-mail chains we get going with some owners to ensure proper operation. So any that are solved here it's really appreciated!

Thank you.

I haven't had any issues lately with short-cycling or strange shut-offs, but then again I haven't had the opportunity to do a cold start in the last few days either. I'll keep you informed.

 

[DaveH]

That is the unit going out on high limit. (safety) High speed fan comes on by the high limit not just by the t-stat.

I haven't found any documentation on it or asked Daryl directly, but, is there a sleep function on the display that you've noticed? My display goes out regularly, then beeps and kicks back on. I refuse to believe it is close to overheating every time it does this, mainly because i'm throwing in 3 or 4 maple/elm/pine splits at a time. It's out right now, about 20 minutes after I place 3 smaller Norway Maple splits (15% mc max) on to a small bed of coals.

Is it a sleep mode type function or is my high limit control too low on the plenum? Thanks.

 

[STIHLY DAN]

You need to call lammpa now! There is something wrong with that controller. Get it straightened out before it gets cold.

 

[DaveH]

You need to call lammpa now! There is something wrong with that controller. Get it straightened out before it gets cold.

Thanks. I figure thats the best bet.

A few minutes after I posted this I checked the furnace, had a nice little bed of coals, went up and turned the thermostat from 68 to 70 and the unit kicked on immediately, showed a 3, and kicked the fan on. This is why I thought it might me a sleep function. I'll call.

Is it possible that this is a function on the newer units?

 

[STIHLY DAN]

No, there is no sleep function. If the low speed fan was not already on, the high speed should not have came on. The 3 of you really need to contact lammpa and get this straightened out.

 

[brenndatomu]

The previously thought to be extinct "Kuuma gremlins"...although VERY rare, turns out they do still exist!

 

[Monaco]

I've done a few cold starts over the last week and no more problems other than a few times of cycling off that could be "normal". I have not experienced the mysterious controller "power off" issue again.

 

[DaveH]

Quick fix I hope. Turned the low limit down to 100. This should keep the fan running on low longer, thus cooling the exchanger and not causing the unit to overheat and shut down.

 

[Monaco]

I can attest that there is no appearance of or anyway to mistake a power failure when you go over heat limit. Leave the ashpan door open long enough, and it'll warn you with a lour continuous beep tone and an error code on the LCD display.

 

[DaveH]

I talked to Daryl today and he confirmed the unit will shut down when it hits its high limit or gets close to it. The high temp alarm must have a different criteria in order to trigger, probably a slightly higher temp.

 

[JRHAWK9]

High temp alarm sounds when the thermocouple senses internal firebox temps hitting a preset limit. The computer sends out a continuous beep and then displays AL on the display. Only thing that can be done about this is putting some tape temporarily over the pilot holes on the primary air supply, which may help calm the fire down sooner. This will sometimes happen when you do a FULL load on top of a full bed of hot coals. The out-gassing from the fresh load can really get hot tripping the alarm for a bit.

The high limit switch in the plenum will turn on the high speed blower when plenum temps reach 220° and turn off the computer when they reach 250°. If your computer is turning off due to high plenum temps then the high speed blower must come on some time before it shuts itself down....otherwise it's not turning off due to plenum temps. Also note the high speed blower will continue to run even when the computer shuts itself down.

per the manual:

The primary fan (high speed) will turn on automatically provided the side jacket is at 105 degrees F (or wherever you have the low limit set to) whenever the remote room thermostat is calling for heat. The fan will also turn on automatically if the plenum temperature rises to the setting on the high limit switch (set at approximately 220 degrees F.) and will continue to operate until the temperature of the plenum has cooled down to approximately 100 degrees F. The high limit is set at approximately 250 degrees F. and if this temperature is ever obtained, the electronic control will be entirely de-energized and the automatic draft controller will close. Conditions will remain in this state until plenum temperature has cooled with large fan running allowing the automatic high temperature cut-out switch to reset the controller.

Unless you have a faulty low limit switch causing your low speed blower NOT to come on, causing very high bonnet temps, my guess is you are not hitting the high limit temp (250°) and the computer is shutting down due to some voltage spike or something in the line. I guess these computers can be a bit sensitive to any kind of voltage spikes/irregularities. Stick an HVAC/meat thermometer in your plenum and monitor your plenum temps, this will help give you a better idea of what's possibly going on.

If the high limit is actually being tripped, I would check to make sure you have your high limit setup correctly and it's not being prematurely tripped.

 

[brenndatomu]

The high limit switch in the plenum will turn on the high speed blower when plenum temps reach 220° and turn off the computer when they reach 250°

Wow that seems high. Many furnace limit switches are set at 200*. Pyrolosis (sp?) begins around ~190* I believe...

 

[STIHLY DAN]

It's not the high limit as the fan did not come on yet. And no alarm was sounded or registered. I still think the high limit is to close, and the bleep in the computer is an issue.

 

[STIHLY DAN]

I talked to Daryl today and he confirmed the unit will shut down when it hits its high limit or gets close to it. The high temp alarm must have a different criteria in order to trigger, probably a slightly higher temp.

What did daryl say about the blip in the computer.

 

[DaveH]

What did daryl say about the blip in the computer.

Power interruption issue, high bonnet probe wired with a ground fault circuit, or possible bad wire.

I double checked my high limit settings, they are good. The furnace is not on a GFI outlet/breaker. It hasn't happened in a couple days. I'll have to keep an eye on it when I'm off for the holiday.

 

[DaveH]

" I still think the high limit is to close"

You mean physically too close to the HE?

 

[STIHLY DAN]

" I still think the high limit is to close"

You mean physically too close to the HE?

Dave, yes to close to the unit but I was referring to Monaco's not yours. I find the answer you received to be hard to believe. Did you tell him that 3 of you had the exact same issue.

 

[Monaco]

Dave, yes to close to the unit but I was referring to Monaco's not yours. I find the answer you received to be hard to believe. Did you tell him that 3 of you had the exact same issue.

I think I might move mine higher just to be on the safe side. may also find some kind of thermometer to stick in there just for information's sake

 

[DaveH]

Since I've turned my low limit down to 100, I've noticed the the fan come on earlier and stay on consistently like it should. I have not had the computer shut down again. There may be no direct correlation, but everything is running fine now.

 

[garmford]

I talked to Daryl about my short cycling and he agreed that the low limit switch could be bad. He sent me a new one and that thing works sweet!! Very little cycling at the start, if at all, and then it cycles at the end when there's just coal. This is how I assumed it should have worked from the start. Again, customer satisfaction at its best! I now have the switch set to 110 for the last few weeks and has been working well

My question for the rest of you users is, what temperature are you getting in the bonnet when the furnace is hot and running at an even keel? I assume this can different for all of us depending on our wood and size of the load in the box. If I put in a decent load and the computer on low, I will be 90-100*. With the same load and the computer on high it can get as high as 110*. It definitely uses more wood with the computer on high! For temperature reading I have a meat thermometer inserted in the front of the plenum about 16" up from the top of the furnace. I also have the static pressure set at .20. I also have cold air return from the existing hvac system attached to the filter box. I keep reading about some of you being able to cook yourselves out of your house with a small load with the computer on low. I can't do that with a big load with the computer on high, unless it's about 35* outside. Now I may have over engineered my duct work too. I created some long runs thinking I was doing the right thing but I'm starting to have my doubts. So I'd like to make sure that the Vaporfire is operating similar as the rest of yours before I start tearing sheet metal apart.

Though I must confess, it's been in the mid 20's here today the house has been at a pleasurable 72* all day with the computer on low. Now that we have cooler weather and the fire can stay lit 24/7, the temp in the house doesn't seem to fluctuate near as much as last month with the continual cold starts from the warmer weather. I may need to crank it up for tonight's single digit temp forecast.

Thanks for any helpful info!!
Happy New Year

 

[STIHLY DAN]

My question for the rest of you users is, what temperature are you getting in the bonnet when the furnace is hot and running at an even keel?

I have a 1/3 load in now, unit on low, computer at 1, low speed fan on, fan on temp set at 100*. Temp at 1st outlet 5 ft away is 102*. This will increase a bit when it hits cruise temp. Generally runs about 112*. My ductwork is not insulated, return is 30 ft long, supply trunk is 35 ft with 9 takeoffs and key dampers in each for zoning.

I like 110 setting on shoulder season and 100 when its cold, You get more heat with lower setting. Allows the fan to run longer when your down to coals.

 

[STIHLY DAN]

Coming into the last 3rd of the burn, #2 on and temp is 112*

 

[STIHLY DAN]

32* outside, started with a cold unit, house was 68 and un insulated concrete basement was 60. House is now 76 and basement 70. This (over heat) was not an accident, No kids tonight so planning on hot, drunken, sloppy XXX!!

 

[STIHLY DAN]

On # 3 at end of burn, 5 hrs in, temp 92*