Measuring CH flow and return temperatures

shiraz99

What do professionals use to measure the flow and return temperatures on a radiator?

I want to properly balance my rads and check whether the boiler is running efficiently as possible.

alanobrien

No idea what heating engineers use but as an engineer myself i use an infrared non contacting thermometer.
It makes the job quite easy.      Something like the one linked to below except mine is more accurate at +/- 1C


https://www.amazon.co.uk/Etekcity-Lasergrip-Non-contact-Thermometer-58°F-1022°F/dp/B01AT9TON0/ref=sr_1_7?crid=37AX64PSLZLIZ&keywords=infrared+thermometer+gun&qid=1665496998&qu=eyJxc2MiOiI1LjAyIiwicXNhIjoiNC43MSIsInFzcCI6IjQuNjUifQ==&smid=A3P5ROKL5A1OLE&sprefix=infra+red+thermo,aps,131&sr=8-7&th=1

Ebe_Scrooge

Stick "radiator balancing thermometer" into Google and you'll get dozens of results, from less than a tenner to well over a hundred quid.  I'd probably suggest that one of the cheaper ones is fine for DIY use - you're not going to be using it very often at all, unlike a plumber who'd use it a lot so could justify spending a lot more on something a bit flashier, easier to use and more accurate.

victor2

shiraz99 said:

What do professionals use to measure the flow and return temperatures on a radiator?

I want to properly balance my rads and check whether the boiler is running efficiently as possible.

Not "professional" equipment, but I got four thermometers from Amazon for less than a tenner:

https://smile.amazon.co.uk/gp/product/B07ZN3QTBV

They all work and agree to within one degree of each other when measuring room temperature. You could put one on the flow and one on the return and do two radiators at a time. Of course you have to give them time to settle, where infra-red thermometers will be instantaneous, but I can live with that.

shiraz99

alanobrien said:

No idea what heating engineers use but as an engineer myself i use an infrared non contacting thermometer.
It makes the job quite easy.      Something like the one linked to below except mine is more accurate at +/- 1C


https://www.amazon.co.uk/Etekcity-Lasergrip-Non-contact-Thermometer-58°F-1022°F/dp/B01AT9TON0/ref=sr_1_7?crid=37AX64PSLZLIZ&keywords=infrared+thermometer+gun&qid=1665496998&qu=eyJxc2MiOiI1LjAyIiwicXNhIjoiNC43MSIsInFzcCI6IjQuNjUifQ==&smid=A3P5ROKL5A1OLE&sprefix=infra+red+thermo,aps,131&sr=8-7&th=1

I've got one of those no contact forehead thermometers that also has a mode for object temperatures, I wonder if this will be accurate enough.

Ebe_Scrooge

shiraz99 said:

alanobrien said:

No idea what heating engineers use but as an engineer myself i use an infrared non contacting thermometer.
It makes the job quite easy.      Something like the one linked to below except mine is more accurate at +/- 1C


https://www.amazon.co.uk/Etekcity-Lasergrip-Non-contact-Thermometer-58°F-1022°F/dp/B01AT9TON0/ref=sr_1_7?crid=37AX64PSLZLIZ&keywords=infrared+thermometer+gun&qid=1665496998&qu=eyJxc2MiOiI1LjAyIiwicXNhIjoiNC43MSIsInFzcCI6IjQuNjUifQ==&smid=A3P5ROKL5A1OLE&sprefix=infra+red+thermo,aps,131&sr=8-7&th=1

I've got one of those no contact forehead thermometers that also has a mode for object temperatures, I wonder if this will be accurate enough.

Well, given that you're looking to measure a temperature difference in the pipes, it doesn't really matter if the absolute temperature reading is accurate or not.  You're usually looking for a 12 degree difference in the 2 sides.  So, a "human" thermometer will be plenty accurate - the only downside is that it's probably calibrated wrongly.  In a human, if your temperature is more than a couple of degrees outside of "normal", you're very ill.  If you are 12 degrees outside of normal, you're pretty much dead.  So I suspect it may not be calibrated to read much outside, say, 3 or 4 degrees either side of 37 degrees.

I might be wrong - if it's marketed as a "multi-purpose" tool, with different settings for "human" and "other things",then it may well do the job.

But like I said, a cheap pipe thermometer for less than a tenner is probably going to do the job "near enough" for most DIY purposes.

shiraz99

Ebe_Scrooge said:

shiraz99 said:

alanobrien said:

No idea what heating engineers use but as an engineer myself i use an infrared non contacting thermometer.
It makes the job quite easy.      Something like the one linked to below except mine is more accurate at +/- 1C


https://www.amazon.co.uk/Etekcity-Lasergrip-Non-contact-Thermometer-58°F-1022°F/dp/B01AT9TON0/ref=sr_1_7?crid=37AX64PSLZLIZ&keywords=infrared+thermometer+gun&qid=1665496998&qu=eyJxc2MiOiI1LjAyIiwicXNhIjoiNC43MSIsInFzcCI6IjQuNjUifQ==&smid=A3P5ROKL5A1OLE&sprefix=infra+red+thermo,aps,131&sr=8-7&th=1

I've got one of those no contact forehead thermometers that also has a mode for object temperatures, I wonder if this will be accurate enough.

Well, given that you're looking to measure a temperature difference in the pipes, it doesn't really matter if the absolute temperature reading is accurate or not.  You're usually looking for a 12 degree difference in the 2 sides.  So, a "human" thermometer will be plenty accurate - the only downside is that it's probably calibrated wrongly.  In a human, if your temperature is more than a couple of degrees outside of "normal", you're very ill.  If you are 12 degrees outside of normal, you're pretty much dead.  So I suspect it may not be calibrated to read much outside, say, 3 or 4 degrees either side of 37 degrees.

I might be wrong - if it's marketed as a "multi-purpose" tool, with different settings for "human" and "other things",then it may well do the job.

But like I said, a cheap pipe thermometer for less than a tenner is probably going to do the job "near enough" for most DIY purposes.

That's a good point, didn't really consider that. I'll have a play later when the heating comes on.

nofoollikeold

For modern systems with condensing boilers it is normal to have a temperature difference of 20 degrees C across the flow and return pipes.  

Apodemus

alanobrien said:

No idea what heating engineers use but as an engineer myself i use an infrared non contacting thermometer.
It makes the job quite easy.      Something like the one linked to below except mine is more accurate at +/- 1C


https://www.amazon.co.uk/Etekcity-Lasergrip-Non-contact-Thermometer-58°F-1022°F/dp/B01AT9TON0/ref=sr_1_7?crid=37AX64PSLZLIZ&keywords=infrared+thermometer+gun&qid=1665496998&qu=eyJxc2MiOiI1LjAyIiwicXNhIjoiNC43MSIsInFzcCI6IjQuNjUifQ==&smid=A3P5ROKL5A1OLE&sprefix=infra+red+thermo,aps,131&sr=8-7&th=1

I've got that exact thermometer and it is great for a lot of uses - everything except getting the temperature of CH pipes, especially if they are shiny copper or stainless steel.  It's good for rads and walls, woodburner, pizzas, you name it, but results from pipes are all over the place.  At the moment, the top of my kitchen radiator is showing 44C, while the feed pipe from the boiler is giving me between 27C and 44C and the return 26C to 35C.  I can comfortably put my hand on the return pipe, but not the feed, so I'm guessing high 40s for the feed and mid twenties for the return.

FreeBear

victor2 said:

shiraz99 said:

What do professionals use to measure the flow and return temperatures on a radiator?

I want to properly balance my rads and check whether the boiler is running efficiently as possible.

Not "professional" equipment, but I got four thermometers from Amazon for less than a tenner:

https://smile.amazon.co.uk/gp/product/B07ZN3QTBV

They all work and agree to within one degree of each other when measuring room temperature. You could put one on the flow and one on the return and do two radiators at a time. Of course you have to give them time to settle, where infra-red thermometers will be instantaneous, but I can live with that.

I also have a pair of the same. Used a plastic Talon pipe clip with a 4mm hole drilled in it for the sensor. Slip the clip over the pipe, wait for the reading to stabilise, job done.

Apodemus

FreeBear said:

Apodemus said:

alanobrien said:

No idea what heating engineers use but as an engineer myself i use an infrared non contacting thermometer.
It makes the job quite easy.      Something like the one linked to below except mine is more accurate at +/- 1C


https://www.amazon.co.uk/Etekcity-Lasergrip-Non-contact-Thermometer-58°F-1022°F/dp/B01AT9TON0/ref=sr_1_7?crid=37AX64PSLZLIZ&keywords=infrared+thermometer+gun&qid=1665496998&qu=eyJxc2MiOiI1LjAyIiwicXNhIjoiNC43MSIsInFzcCI6IjQuNjUifQ==&smid=A3P5ROKL5A1OLE&sprefix=infra+red+thermo,aps,131&sr=8-7&th=1

I've got that exact thermometer and it is great for a lot of uses - everything except getting the temperature of CH pipes, especially if they are shiny copper or stainless steel.  It's good for rads and walls, woodburner, pizzas, you name it, but results from pipes are all over the place.

I also have a pair of the same. Used a plastic Talon pipe clip with a 4mm hole drilled in it for the sensor. Slip the clip over the pipe, wait for the reading to stabilise, job done.

Thanks, but my comment was in response to alanobrien's link to the Etekcity IR Thermometer - really useful device, just not for pipes!