Do you know? Thermocoupler..

[walkerj001]

Hello I am new to the forums and got pointed to this forum for assistance. This may be a basic question , but I am still learning and wanted to be sure I am doing this correctly. What I am doing is installing a thermocouple into my chimney pipe so I can get a digital readout on a PID controller from inside the house. The question I have is what would be the best location to install this thermocouple? I have seen where people stated 18" from top of woodstove, but that was with woodstoves that had chimney pipe coming out from the top of the woodstove and not the back. I have attached some pictures for reference. Also I know that thermocouple should be before the barometric draft regulator.

Unit is a US Stove 1557m

Thanks in advanced for your assistance !
Greatly appreciated

 

[PassionForFire&Water]

What do you want to accomplish with this reading?
Is it just to know how hot the flue gas is?
I would say as close as possible to the flue collar of the appliance

 

[warno]

My dad's chimney has a temp sensor to tell him how hot things are getting since the chimney runs through the center of his house. he has an alarm set at a certain temp to sound when he needs to go choke down the damper if he gets busy doing something else. his sensor is just before the chimney punches through the basement ceiling. so I would say about 6-7 feet from the wood furnace flue exit.

 

[Nofossil]

For me, flue temp is more about comparing than about absolute measurement. I want to see if changing boiler operation affects flue temp, and I use flue temp to tell me to stop making excuses and clean the heat exchanger tubes. Finally, I use it to sound an alarm if it gets too high - maybe someone got distracted and forgot to close the damper to force downdraft operation.

None of these uses depend on perfect placement. I have mine about 4" from the back of the boiler, and near the center of the flue.

 

[jebatty]

Ditto with Nofo except my senser is about 18" above the collar and also shuts down the draft fan if the temperature exceeds 250C. With the draft fan off the flue temperature drops rapidly.

 

[walkerj001]

What I am trying to do is get a close comparison in temp between a magnetic temp guage and thermocouple. I know one is measuring surface temp and another is measuring flue gas temp, but consistently walking back and fourth gets annoying. I plan to run a temp guage to my living room where I usually am. Also the alarm feature is nice in case it gets to hot while I am sleeping. I also read it needs to go before draft regulator otherwise readings will be incorrect. Im not an expert thats why I am reaching out !! Thanks everyone

 

[Nofossil]

In my experience, you'll *never* get a close reading between the two. Surface temp in my case is a lot lower, and I think that's what most folks have seen. True flue temp as measured by a thermocouple is much more accurate and responds to changes more quickly.

I use a magnetic to let me know when to switch to downdraft, but that's only because I haven't got around to displaying the thermocouple temp in the boiler room yet.

 

[maple1]

Don't think it matters a whole lot, as long as it is before a baro damper. Think my probe thermometer is about 1.5' from the boiler outlet.

Just stick it in so the tip is in the middle of the diameter - then stick your magnetic thermometer on the pipe beside the probe. I have a magnetic beside my probe thermometer - they are 100c different when burning. (Probe is higher, of course).

Also why IMO magnetic gauges can be dangerous, it's a lot hotter in there than what they say....

 

[STIHLY DAN]

Why is your cleanout facing the wall?

 

[brenndatomu]

I don't think it will matter much where you put it as long as it is rated to the temperature it will see. Example, a TC that is rated to 800*F that is mounted close enough to the stove to see 1000-1200* internal pipe temps, it may not last too long.