Is there a decent magnetic flue thermometer?

[neiln]

Not really complaining as they are so cheap, but I've got half a dozen and they all start ok but soon miss read by a huge amount,  50-100C or more under, always under. I can only imagine the curly bimetal strip gets too hot and bends or goes limp or something.  But, if there is a decent brand that doesn't do this, I'm interested!

[slim reaper]

I've got clearview ones on my 

stoves and when I check with a Fluke IR thermometer they are well out

[sandspider]

I've got a Bluedot (I think) one on my smaller stove. I don't have an IR thermometer to compare, but it seems to read low to me - only 100C ish when the stove is running nice and hot.

 

My Burley stove manual says not to use them, as the stove is so efficient the flue temp is quite low - to get a flue thermometer reading in the healthy range would mean massively overfueling the stove.

 

Maybe get an IR thermomemter instead?!

[slim reaper]

2 hours ago, sandspider said:

I've got a Bluedot (I think) one on my smaller stove. I don't have an IR thermometer to compare, but it seems to read low to me - only 100C ish when the stove is running nice and hot.

 

My Burley stove manual says not to use them, as the stove is so efficient the flue temp is quite low - to get a flue thermometer reading in the healthy range would mean massively overfueling the stove.

 

Maybe get an IR thermomemter instead?!

Seems a strange one by Burley, all they need do is give a temperature range.

[GarethM]

Well they are only a broad range indication of the temperature, fitting a threaded insert bolt would be more accurate as your installer could use it to check flue gases.

 

However if you look at the burley mentioned, the flue gas depending on model can be as low as 122c.

Edited September 30, 2022 by GarethM

[sandspider]

20 minutes ago, slim reaper said:

Seems a strange one by Burley, all they need do is give a temperature range.

I suppose they don't want people using the standard flue thermometers and melting their stoves getting the flue temp to 200C as the thermometer advises!

[openspaceman]

2 minutes ago, sandspider said:

I suppose they don't want people using the standard flue thermometers and melting their stoves getting the flue temp to 200C as the thermometer advises!

Quite so.

 

It looks like Burley stoves give out a high percentage of the released heat to the  room and thus the flue gases are much cooler than a conventional thermometer can indicate. On commercial biomass boilers I saw flue temperatures typically around 115C. This of course means they are running very efficiently without the risk of condensation in the flue.

 

With a temperature at these lower ends you will almost certainly require a well insulated chimney to prevent the water vapour condensing.

[Rob_the_Sparky]

I honestly don't care too much what the thermometer says.  It tells me if it is too hot or too cold but now I have had a few years at it you don't need the thermometer to tell me what the temp is.

[neiln]

True it's not really needed, and I've got an IR thermometer..

[openspaceman]

43 minutes ago, neiln said:

True it's not really needed, and I've got an IR thermometer..

I must treat myself to a new one, what's the highest temperature they measure now?