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Fluke 62


Ben H
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I don't use the infrared thermometers at this time. When checking register air temperatures, you can get different readings depending on whether your infrared 'sees' the metallic grille or the black insulated interior. It's an objectionable difference, in my opinion.

Maybe I'll begin using them in instances where the ceiling height is out of reach. I've had lots of Flukes. They seem to be a good rugged brand.

Marc

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I don't use the infrared thermometers at this time. When checking register air temperatures, you can get different readings depending on whether your infrared 'sees' the metallic grille or the black insulated interior. It's an objectionable difference, in my opinion.

Maybe I'll begin using them in instances where the ceiling height is out of reach. I've had lots of Flukes. They seem to be a good rugged brand.

Marc

Really? You get on your ladder and check the temperature at every register?

I consistently get good readings with my IR thermometer. Yes, you are getting the temperature of the register, not the air, but what difference does it make?

The key is the spot to distance ratio. Get at least a 12:1 resolution.

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Really? You get on your ladder and check the temperature at every register?

I consistently get good readings with my IR thermometer. Yes, you are getting the temperature of the register, not the air, but what difference does it make?

Google this term to learn more about the shortcomings of radiation based, non-contact thermometers: Emissivity

I'm 5' 10". If it's an 8' ceiling, I simply extend my hand upwards. My thermocouple has about a 2' lead on it.

Marc

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Marc, why do you need anything more than an approximate temperature at the registers? If you are trying to get an accurate delta T, the register is not the place to do it no matter what thermometer you are using.

True, the plenums are the best place because it leaves out duct losses but the way residential systems are built here, I'd usually have to punch a small hole in the supply plenum which I arm unwilling to do during a home inspection. I'd punch it if it were an HVAC service call though.

During a home inspection, I look for 12 to 18 degrees of temperature differential between air return and a distant ceiling register. If the differential is off, I recommend service, I do not specify 'air handler' or 'furnace', just 'HVAC system'.

You'd be surprised how much the emissivity can vary between black insulation and white painted grilles. Try it, I did, then switched.

Marc

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True, the plenums are the best place because it leaves out duct losses but the way residential systems are built here, I'd usually have to punch a small hole in the supply plenum which I arm unwilling to do during a home inspection. I'd punch it if it were an HVAC service call though.

Marc, my friend, you have to pick one side of an argument and stick to it... if emissivity affects readings then just shoot the plenum sheet metal on the supply and return after 5 or 6 minutes of operation. No holes, no different surfaces, no different emissivity. Even if the temps are skewed they're skewed proportionally.

That said, my Raytek Ranger reads my mouth interior @ 98.2 degrees.

In comparison tests pitting the Ranger against a bulb thermometer I shoot the sink basin after running hot water for three minutes and then immerse the thermometer in the water stream and the two results are always less than .5 degrees different.

That said, my Raytek has a spot ratio of 1:60 and it cost as much as my moisture meter. I'm not sure how the less expensive models perform but my bet is they're useful as well as non-intrusive.

Back in the day when I was mostly dirty, I used the Ranger to diagnose misfiring diesels by shooting the exhaust manifold near each cylinder. Picking the cool cylinder let me confidently replace one injector instead of a set 6 or 8.

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