Checking Digital Thermostatat Inside Temperature

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One of the digital thermometers ranges from about 66->86. I do not know about the other. Are you suggesting that I submerse the other? I have no idea if it is waterproof.
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Total submersion is the only accurate test.
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Christopher A. Young
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Only for thermometers that are intended to be used submerged. I have a number of glass lab thermometers (mercury and alcohol) and at least half of them have a line on the body to mark how far they are supposed to be submerged. The part above that is expected to be in air.
In addition, many bimetal dial thermometers are not waterproof and will be ruined if you submerge them. The bimetal element is only in the lower inch or so of the hollow steel shaft, and that's all that needs to be submerged.
Then there are electronic thermometers that are not waterproof and will be ruined even faster when submerged. In these, the measuring element is a small thermistor bead, and it's at the end of the metal shaft.
    Dave
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One of the digital thermometers ranges from about 66->86. I do not know about the other. Are you suggesting that I submerse the other? I have no idea if it is waterproof.
Sorry I was thinking of a glass tube thermometer, that is, an analog device.
The trouble with digital is the rounding error. On analog you might read 70 and a half. But one digital might sense it as 70.45 and report 70 and another might sense 70.55 and report 71.
This is exactly why I bought a glass thermometer just to check my digital thermostat. They are less than $5. Then if you really want to make yourself conused, take the room temperature in various parts of the house.
Charlie
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Does it have patches that change colour to indicate temperature? If so, that's an LCD thermometer, not an electronic digital thermometer, and unlikely to be very accurate.

More likely, the digital thermometers will display fractional degrees. So the one will report 70.5 and the other will report 70.6. It probably won't be *accurate* to 1/10 degree, but have enough precision that you don't have to worry about roundoff error.

Analog glass thermometers have infinite measurement precision (you can use a magnifier to resolve fractions of one scale marking), but their accuracy is not infinite, and depends on manufacturing accuracy. There are accurate and inaccurate digitals, accurate and inaccurate analog thermometers.
    Dave
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On Oct 14, 12:29pm, snipped-for-privacy@cs.ubc.ca (Dave Martindale) wrote:

Yes, the patches change colour and I tossed it a couple of days ago.
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Make ice cubes out of distilled water. Make a mixture of ice cubes and distilled liquid water, and shake it up good. When you're sure it's all 32F, soak the thermometers. the one which reads 32F is correct. The others are not.
Only an engineer could spend so much time on two degrees.
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And even by doing all that you are only sure of one point. It could still be way off at 70 deg.
He should just put a piece of tape over the readout and set it to the comfort zone.
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you do know that heat comes out of the thermostat. so putting a thermometer on top will not give accurate reading. my bad, dumb question. obviously you dont or u wouldn't put it on top.

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You are right. I never thought of that.
When we moved in here, the mechanical thermostat was off by about 8 degrees. We would set the heat for 68 and be sweltering.
Right now, these 2 standalone digital thermometers are really bugging me. One is at 71 and the other somewhere between 72 and 76. I think it is time to toss the second.

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Bob wrote:

that various electronic units have different thermal mass, i.e. they take longer or shorter times to warm up or cool down. For instant reading a small thermocouple will give the fastest response .... but don't stand close to it or it will be reading heat radiating from your body.
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most electronic thermostats use thermistors. about the size of a small seed.
--
Jim Yanik
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the actual temp is some thing about 68 to 71.
s

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Who cares what the numbers are? The *right* temperature is the one that makes you comfortable. Somehow the numbers seem to have become more important than the real goal.
Different places in your home will vary more than that.
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Best is to get a few more thermometers. Then go for five out of seven matches.
Of course, the actual temperature of the 68 and 69 may be 67.9 and 68.6 rounded off.
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That is how I used to shop for thermometers with red liquid years ago.
A normal topic of conversation here (southern Ontario) is 'what setting are you using for your furnace (or air conditioner)?' That seems kind of irrelevant now in terms of what we are all posting about here.
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On Oct 12, 6:24am, snipped-for-privacy@columbus.rr.com wrote:

I think that the analytical side of me is taking over. I thought (obviously incorrectly) that a digital thermostat (or thermometer) manufacturered fairly recently should be 'calibrated' out of the box to about +/- .5 or so. As a result, I was unpleasantly surprised when the thermostat and 2 digital thermometers were so far apart.
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I have calbirated units, I must because the city can fine me for not supplying tenents with enough heat. You need a marked calibrated glass mercury or liqued filled thermometer, heating supply places have them but call first or go online to like Granger. I have tried the ice method but its not easy to get it exactly. Then I buy thermometers I can adjust or slide up or down the thermometer in its casing. You can then adjust the digital to match. 1 degree is important to me since I pay thousands a month in Ng, tennants lie and say they are always cold, I just had one couple say they were cold when it was 74 in his apt and he had his T shirt on. They proceeded to run their electric heater to keep the place 79, ran up a 800$ electric bill, moved and stiffed everyone. 1 degree makes a difference in my gas bill. Stores sell uncalibrated humidistates and thermometers.
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Adjust the digital? Do you mean determine that 74 on the calibrated thermometer is 72 on the thermostat, and then set the later to 72? or actually *adjust* the inside temp of the thermostat to a true 72 (using the thermometer)?
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Find true temp with a glass analog with scale printed on thermometer, then adjust thermostat to match, there are settings if its a quality unit, digital thermometers usualy cant be adjusted, but some can.
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