QF 7100 Thermometer Location and Temps

[kiltedpiper98]

Fellow Quadrafire 7100 owners, do you all have rough temperatures that you use to work your fireplace? If so, what are the temps, and how and where do you measure them? I have read on the forum about overfire situations, and looking into the gates of hell during that situation. There have been sometimes when it looks like there is a significant amount of fire. I have a magnetic stove thermometer on the top of the door, and get generally about 300 to 400 degrees, with some good secondary flame without much primary flame and the ACC all the way closed. Should I use more wood, keep the ACC open more, and get temps up to 500 degrees at that point to get good heat?

Also, the fan is quite intermittent even at high temps (seems more steady at low/coal temps). Does everyone have this issue?

Thanks.

 

[73blazer]

I have a North Star unit, same basic unit as your QF7100 (most p/n's are the same, your firebox is bigger and you have some additional options), remove the front fasicia (4 screws, designed to be removed so you can clean the bottom area around the fans out) and put the magnetic thermo on the steel chimney pipe above the stove. After you re-install the front fascia, you can view it pretty easily through the top vent plate. It's not in your way or an eyesore this way.
Anyhow, the temps on these magentic thermo's vary quite a bit, I have the rutland version, and I usually run a cycle after a new load, I leave the air full open until the temp reaches 500->600 (anywhere from 10-20 minutes, needle straight up or 10degrees or so beyond past straight up), then I open up the 'timed air' then set the air to almost full close, I close it down to about a just a shade, mabey 1/4" away from full close. If you have dry wood, it'll secondary burn for several hours this way. Late in the coal stage, I open the air up to 3/4 or so open and it'll maintain a decent heat output for another hour or 2.
I've had it up to 750 before, didn't seem to cause an issue, but that's getting to the edge of my comfort zone.

As far as the thermocouple kicking the fan in and out. 2 things. First, on every load, scrap away all the ash in the center of the floor, get the ash off to the sides or out completely, get nice clean red hot coals in that area. The thermocouple that controls the fan is right underneath the floor here, so keeping the insulating ash away from that area helps that alot. I find I need to remove ash at least once a day to keep the most optimized burn cycles going. Usally I remove some ash first thing in the moring when it's had a chance to burn down alot and there aren't so many hot coals. I wish there was a rake tool or something, but I move the shovel around and get the coals off to one side and get most of the ash out.
2nd, I wired the thermocouple override switch in my setup (was outlined in the instructions). It's a simple light switch next to the variable fan control. . Most of the time, I just leave the override switch on, because the thermocouple kicks the fans off too early in my opinion. Only time I won't have the override switch on is when I leave for a few days and the fire's still burning when I leave. Thermocouple controlled fan is a neat idea, but execution is another story. Alot have reported these going bad fairly often too. Anyway, if you keep the ash from insulating, the center area of the stove, even with my override switch off, the fans never kick in and out, they just shut off too early.

 

[kiltedpiper98]

73Blazer - thanks for the info. Good idea on placing the thermo inside the faceplate on the chimney. I will try that soon, and see where my burn temps are. On the front face, it takes a while for it to get over 300, in fact in can run with secondary flames at around 200 degrees on the Rutland t-meter.

We the fan setting, I have mine set up with the override as well. It works, but I would prefer to leave the thermocouple switch to work at night. If the fireplace has been rolling for a couple of loads, no issue, but if we start up a load for night the auto-on doesn't seem to work.

 

[Village Idiot]

+1 On placing the thermometer on the chimney pipe behind the fascia. I would suggest that you loop a wire around the pipe and use it to hold the magnetic thermometer in place since high heat reduces the magnetism. I found the thermometer very useful until one morning I came down to reload and could not see it. With a flashlight I could see that it had fallen off onto its face. It makes me wonder just how hot it was to make it fall off? The next time I have the fascia off, I will wire it in place.

I had some trouble with my snap disk working properly at first. I finally clued in about scraping the ash away from the center area on the floor of the box. Though it was still intermittent at times. Quadrafire agreed to have it replaced as a warrantee item. Once we had the hatch open, we saw that the metal clip that holds the snap disk in place was not doing a very good job. The original disk was working fine when heated with a lighter.

We think that as the fireplace heated up, the clip would expand and create an air gap between the disk and the bottom of the plate. As we know, air is a good insulator. So, we bent the clip to make a better hold and I have not had an issue since.

 

[docruss97]

Great thread! I have the North Star and have been wandering how to monitor the temp. Above was mentioned placing a temp gauge on the pipe above the stove…since the fan moves a massive amount of air past this point would the gauge give an accurate reading, i.e., the flat temp gauge on a round pipe would catch substantial amounts of air on the sides? The reason I want to measure the temp is that recently the stove seems to become a “nuclear reactor†at times. To get this, I get a nice bed of coals, stock it full for the night, let it burn hot for a bit to get everything going, then I shut turn it down incrementally over 10-15 min. Once I have it nearly shut down the secondary burn kicks in and the fire becomes HOT I can shut the damper all the way down but the stove continues to burn (secondary) like crazy and gets very hot. It will have secondary burn for 2-3 hours (some times less). I bought a Rutland temp gauge and stuck it on the top of the door last night, it was 475-500 F for about 2 hours during the completely shut down secondary burn. I assume the EPA certification requires at least some air to the stove for complete combustion even when totally shut down? Is this “nuclear reactor†normal in you experiences? Maybe I am just learning how to fire it correctly? The "unstoppable burn" makes me nevous but it may be normal for EPA secondary burn units? I burn seasoned elm and oak. I try to keep it going 24/7. I’ve had the stove since last March. I live in Oklahoma.

 

[Village Idiot]

I too experience these kind of burns and admit that I have lost some sleep over them. Over the lat few weeks, I have come to terms with them. I do make darn sure to keep the air control all the way down once the fire is fully engaged. Then once the bowels of hell have begun to reduce, I open it back up if I need the heat output to keep up.

I have tried closing the OAK lever, but it doesn't seem to make a difference. Last night I was thinking how nice it would be to close down the air "just a littlt bit more" to calm the fire down. Of course, that may end up going counter to the EPA nature of the stove.

 

[docruss97]

Good to hear that someone else has experienced this. Here is some info about the OAK system I have discovered. The OAK (outside air kit) lever does open and close a "flap" that allows outside air to come in; HOWEVER, it simply opens up under the stove letting outside air into the space around the stove. It is not a sealed air intake system, so combustion air is being drawn from the room and is being replaced with outside air. The OAK system simply opens up a "hole" to the outside to eliminate any negative draw on the stove. As long as you have a drafty house (or a window cracked) you can run the North Star with the OAK lever closed. Even though Heat and Glo states you MUST have the lever open I went to the dealer and dissected the floor model. The combustion air is drawn in directly under the middle of the front, while the air from the OAK is let in to the space surrounding the stove on the lower right of the unit.

 

[Village Idiot]

Ah-ha! It all makes sense now. I was wondering if the OAK was more of an inside/outside bypass that a single source duct. When experimenting, I would notice the sound of air being consummed conagend when I flipped the OAK lever. Also, it explains why cold air comes out the bottom fascia vent when the stove is out and the OAK lever is open.

This is kind of disappointing to consider. In a true over fire situation, there is little that can be accomplished by closing the OAK. I would be curious to know what the reasoning was behind "crippling" the OAK in ths manner?

Regardless, I really do like my 7100. It keeps my 2900 sq/ft 2-story house nice and toasty. It even does a decent job with the basement if I turn the HVAC fans on.

 

[kiltedpiper98]

Thanks for sharing your experiences. I had heard the OAK vs inside air issue. I actually posted a YouTube video on it, and someone posted there about it. My dealer was surprised by that and called the factory, they verified that it is inside or outside air.

I have the nuclear fire sometimes too, that is what got me thinking about the thermometer. I have moved it to the new location, but too warm for a fire. I do find if I dial the air back quickly, I can avoid the nuclear fire, but my temps (on the front face) stay between 200 and 300 degrees, but I have the aurora borealis effect, blue flame and some secondary action, but not a significant amount of heat.

 

[kiltedpiper98]

Village Idiot - what temps do you run your 7100 at? Is there a temp you close the door at, then a temp you start to close down air, leave it at cruise, etc?

 

[libertyridge]

We need someone to make a simple magnetic thermometer so it can be placed in the best location on an insert and easily viewed. A remote sensor made for high temps like those oven probes would be great. Or a simple spring loaded thermometer, with an extended dial. Or.. Somebody with lots of time just tell me the correlation between the stove top temps,stove pipe temps, and temp on front of stove.. So when i look at thermometer on front of stove and see 450, it means my stove top is 550, and stove pipe is 650..
Thanks in advance

 

[Village Idiot]

Village Idiot - what temps do you run your 7100 at? Is there a temp you close the door at, then a temp you start to close down air, leave it at cruise, etc?

Sadly, I am not sure what temps I am running at. That dang magnetic thermometer fell face down shortly after I put it in place. I blame inertia and too many after school activities for my not fixing it. R/R the fascia is not difficult, but a hassle none the less. I do hear the pointer of the thermometer moving when the stove is heating up from a cold start.

From what I remember, my peak cruising temperatures were showing as ~750 (thermometer placed about 5" above top of stove.) I close the doors when I am convinced that everything is well lit. Frequently, I will slowly close the doors and everything mostly goes out. I will then open up again and give it a minute or so and try again. If you get down low and look in the top above the baffle, you can just see the flue. If I see flames start going up the flue, I close the doors and let the heat "soak" for a bit, then open up again if necessary.

Once I am convinced the wood is sufficiently lit and secondaries are starting to appear, the doors are left closed. I then reduce the intake air a little at a time over about 5 minutes. Then I let it cruise. Eight to ten hours later, lather, rinse, and repeat.

Sorry I cannot provide more detailed temperature readings. This may be the impetus that I need to go get it back up and useful.

I do think that when the thermometer fell down it was a blessing in disguise. It forced me to pay more attention to how the stove was running overall rather than focus on temperature. My stove and I have an understanding now and my skills running it seem to get better with every burn. Though, good dry wood is much more important than how I light it. Last night I did a cold start and had the stove up and running with a full load in 23 minutes. (From what I understand, if I were to use Super Cedars it should light itself. Gotta get me some of those someday.)

 

[docruss97]

The last two nights I have used the Rutland temp gauge placed on the upper portion of where the doors meet. With the doors or the air open it is likely reading low due to the air cooling this location. Having said that, once I get the stove roaring and I neck it down to get the secondary burn going the stove temp sits at 425-475 F at this location. I am not sure what this correlated to as far as top surface or flue temp, but since the baffle directs hot gases and flames right past this location it may be as good of spot as any. It is not a long term solution as it barely fits and looks funny (my wife hates it). I need to find a small temp gauge, maybe 1.5 inch? Any ideas???

I do my fires similar to Village Idiot. With the door slightly open I allow the wood to completely catch fire. I then close the doors but lease the air intake totally open, this temporarily slows the fire down. Once the fire is really going (stove/pipe producing pops and purr sounds) I close it down to around ½ to 1/3 open. If it is the final load for the night I will close it completely after about 5-10 min (secondary burn is going good). If I am around I will leave it about 1/5 open. In order to know where the damper is set I used some high temp silver paint and painted very small markings on the top of the grill above the air controller. I marked totally closed and opened and 4 markings in between. You do not see them unless you are right there. However, it is easy to see where it is set with out moving it and it allows for a common language between my wife and I as to where it is set. THANKS to all for the GREAT info. Keep it coming!!

 

[Village Idiot]

it allows for a common language between my wife and I as to where it is set.

Great idea. I am going to look into putting some unobtrusive marks on the air control lever this weekend. There have been multiple misunderstandings between me and Mrs. VI in the stove control arena. It has always been my fault of course.