Stack temp gauge placement on Drolet escape 1800?

[Mark Richards]

First I'll tell you that the stove is a Drolet Escape 1800 freestander and I have been having great luck with getting fires started and then getting the Secondarys to fire off. Actually the stove seems to be idiot proof and has been very controllable using the damper. I havent got it rip roaring yet with a full load but next weeks weather will probably allow me to do that. My question is related to the construction of the stove and how it might affect the temp reading of my thermometer. The stove has a shroud (on the top surface)that extends from the back of the stove to in front of the stovepipe connector by about three inches. The instructions for the thermometer say to place it 18 inches above the stove top. When I place it there I really have to let the fire inside my stove roar wide open to get the reading to 350 degrees and it seems to use most of the fuel to get there. If I place the guage on the stove top I'm running around 475 to 500 degrees. So my question is do you think that the shroud is acting like a clearance reduction thing much like a sheet of steel on your walls 1 inch from the wall surface. When I place the guage around 10-11 inches I easily get to the 350-425 degree range after 7-12 minutes and then shut down primary air and all is good? What to think ?

 

[Sprinter]

What model thermometer do you have? Do you have a double wall stove pipe or single wall?

It sounds like you have a flue thermometer designed to measure flue gas temps. Those are calibrated to be used a certain distance up the stovepipe. If it's a magnetic type, it should only be used on single wall pipe. Probe types are made for double wall pipe. That makes a big difference. But if you have the right thermometer for the right pipe, then you should put at the recommended height.

I suppose that step top could make a difference, though, if it's a magnetic type. Those thermometers are just measuring indirectly and could be influenced by a lot of things. They're not exactly known for precision anyway.

 

[Mark Richards]

What model thermometer do you have? Do you have a double wall stove pipe or single wall?

It sounds like you have a flue thermometer designed to measure flue gas temps. Those are calibrated to be used a certain distance up the stovepipe. If it's a magnetic type, it should only be used on single wall pipe. Probe types are made for double wall pipe. That makes a big difference. But if you have the right thermometer for the right pipe, then you should put at the recommended height.

I suppose that step top could make a difference, though, if it's a magnetic type. Those thermometers are just measuring indirectly and could be influenced by a lot of things. They're not exactly known for precision anyway.

Thanks and yes it is a magnetic type and I am using single wall pipe. I think I'll go ahead and get something alittle more accurate.

 

[oldspark]

If you are putting that magnetic type on single wall stove pipe 18 inches above the stove and it only gets to 350 something just dont add up, it should be higher then that, you know it reads higher by the reading you got off of the stove.

 

[begreen]

Surface thermometer temps are not a direct indication of the inner flue gas temps. On some stoves, especially those with a 90 above the stove, you can get different surface readings at the same height, but at different points around the pipe. Try this with an IR thermometer and you can see a measurable variation. My guess is that this is because the gases are swirling up the pipe. A 350F surface temp means it is more like 525F to 600F inside the pipe. 350F surface temp is not unusual. Note that stove pipe thermometers as opposed to stove top thermometers show 350F in the correct burn zone.

Don't run the stove with the air wide open. Once the stove is going well, close the air down incrementally over time so that the flame is lazy, but not out. You will see the stove top temps climb and the flue temp drop. This is perfectly normal on an epa stove. And put the thermometer a little lower or on another side of the pipe at 18" to see if it's hotter on that side.

 

[oldspark]

I beg to differ, been looking at a magnetic temp gauge (different brands) for over 30 years, 350 temp is nothing 18 inches above a wood stove, both my old one and new one get hotter then that in a heartbeat. After the fire settles down yea 350 is a good temp but on start up and reload 350 is nothing.

 

[begreen]

How many stoves and different flues for over 30 years? Different stoves behave differently as do different flue setups. Do you have double-wall pipe now? A probe thermometer will react much more quickly and accurately because it is in the middle of the flue gas stream.

Seriously, if you go back over threads you will see lots of different flue temps. Sometimes it's the stove's personality or efficiency, sometimes it's the flue setup, sometimes it is also due to inaccurate thermometers. Even with a straight up flue the Castine ran with lower flue temps than the T6. And our old Jotul 602 would heat up the flue pipe almost instantly.

 

[oldspark]

He has single wall pipe.

 

[oldspark]

How many stoves and different flues for over 30 years? Different stoves behave differently as do different flue setups. Do you have double-wall pipe now?

Seriously, if you go back over threads you will see lots of different flue temps. Someitmes it's the stove's personality, sometimes it's the flue setup, sometimes it is also due to inaccurate thermometers.

Been reading flue temp posts for a long time, 350 is low for start up and reload.

 

[oldspark]

We are talking start up and reload here.

 

[begreen]

You're right, the most common cause is poorly seasoned wood, not the thermometer placement.

 

[Sprinter]

Flue thermometer accuracy issues are a common topic here. The magnetic type is convenient, but will be subject to all kinds of influences. I'd suggest the Condar Chimgard that begreen showed. It's still a bimetallic, but the probe will be looking directly at the gasses. Follow the instructions for height above the stove. It's accrurate enough to keep you out of trouble.

If you want better accuracy, you could look into a thermocouple setup.

 

[oldspark]

I double check mine with an IR testor, its within 50 degrees up to 500 or so and then it can be 100 degrees or more off.
I agree with sprinter, its good enough to keep you out of trouble.

 

[Sprinter]

Flue thermometer accuracy issues are a common topic here. The magnetic type is convenient, but will be subject to all kinds of influences. I'd suggest the Condar Chimgard that begreen showed. It's still a bimetallic, but the probe will be looking directly at the gasses. Follow the instructions for height above the stove. It's accrurate enough to keep you out of trouble.

If you want better accuracy, you could look into a thermocouple setup.

Correction on that for the record. The "Chimgard" is the magnetic model.. I would suggest the "FlueGard" which is the probe model.

 

[begreen]

FlueGard is designed and calibrated for double-wall pipe. The OP has single wall pipe.

 

[Sprinter]

FlueGard is designed and calibrated for double-wall pipe. The OP has single wall pipe.

Okay. I thought it should work for single. An email reply from the company said that they have tried to make it work on single, but it isn't accurate enough.