Which infrared thermometer to buy ?

[ewansdad]

Hi all.

I want to get one of these but dont know which one to buy or where from. I will be using it mainly for balancing radiators and getting my flow and return pipe temp differential. May use it for other things too.

Or should i be buying clamp on pipe thermometers? Or what else?

I dont mind what they cost within reason - dont want to buy a cheapie and find out it is inaccurate or basically rubbish.

Thanks, stu

 

[ianniann]

If you are going to be doing a lot of boiler work and radiator balancing then the clipons might be worth getting. They are more accurate but slower and more fiddly to use.

The infra-red thermometers are instant but not very accurate and even less accurate reading small objects and metal surfaces. Cheaper models (often look a bit like keyrings, available for about ten quid) are effectively useless for measuring the temperature or metal pipework, because the reading area is too large. They can be used to measure the bottom corner temperature on a radiator within a couple of degrees which is adequate for DIY balancing.

The next step up is middle-range gun style thermometers which have a narrower reading area but are still not very accurate on metal. You can put black tape on pipework and get a better reading, but then you can also use a clip-on thermometer

Top of the range IR thermometers have emissivity adjustments which make them much more accurate for reading metal surfaces and usually an even narrower beam, but they are hundreds of pounds.

One of the most important things to note until you get to really expensive models is the focus level. 1:1 on a cheap model means it measures an area as wide as the distance it is from the thermometer, which means you need to be almost in contact with most objects to get a sensible reading. Middle range thermometers are usually in the range 8:1 to perhaps 20:1, meaning you can read an area 1cm wide from 20cm away.

I can't tell you the best brand to get. There are some remarkably cheap ones available on the internet, usually shipped from the far east. Build quality is pretty low but for occasional use they work just as well as better built ones.

 

[brig001]

For the money, it's hard to beat these http://www.maplin.co.uk/Module.aspx?ModuleNo=220790

But, as ianniann says, it has a wide viewing area and you need black tape or similar to read shiniy surfaces.

 

[ewansdad]

Thanks chaps.

This is going to be for DIY use only.

How about a dual input digital thermometer with 2 k type thermocouple probes? Found one for £60.

stu

 

[Agile]

Thats the kind of thing that you need.

Although I do have dual input meters I usually use a press on single probe as its so quick to move and responds within a few seconds and is far quicker for me to use.

Setting rads is only ever very approximate at best. But if they are all set up consistently then they will operate together as best as can be done.

The infra red ones are very good for identifying heat loss areas and by pointing at walls gives a very quick assessment on the effectiveness of the rads at heating a room in terms of heat output.

Tony

 

[ewansdad]

Thanks agile.

Do the probes have to be clamped on the pipe or just pushed on?

stu