Fool temperature probes ??

[Chaboum]

Hello, I come to ask your opinion about something that "bothers" me a little about me. Coincidence? fixation ? exaggeration?
in short I explain:

in a room that I use for storage, then the boiler room on the other hand I have several appliances: freezer, solar water heater, boiler. I have the impression (I understand and realize over time, and I begin to make links between these problems:) all the temperature sensors in this room are distorted:

- my freezer tells me -18 ° while actually inside it is -24 ° (tested with several thermometers)

- my solar water heater gives me weird T ° on the T ° of the water coming down from the roof: example 60 ° on the roof starting from the panels, arrival at the bottom the water would only be 58 ° 57 ° 55 ° until stabilizing at 50 ° after qq time, while above the T ° remains at 60 ° (10 ° loss down 4m !!!)

- my boiler: it returns the ambient temperature of the house to me: well here too it is completely wrong 2 ° difference, which comes closer or closer at certain times.
- ditto for its outside T ° probe: in winter 2 ° difference (by -10 °) and in summer it is about the same !!!!

boiler probe changed = same
solar panel probe ditto = ditto
freezer: the seller said to me: at first it is normal, the freezer is half empty.

but there it is full and it has not changed anything !!! So he said to me: -18 ° is the safety threshold, I prefer it to be -24 °, it's safer

So please !!!! my sensors lost their mind ????? but because of what ???

[Flytox]

Hello chaboum

Thermometers of any type are given with a certain tolerance, margin of error (class) which is not always displayed. In some cases the error can be very large (> + or - 20%!). The manufacturers of all the materials you mention do not provide a calibration certificate / temperature verification report. So you can expect a lot of things from the display.

Often all these temperature indicators are offset from the exact measurement but their error is almost constant in the measurement range where they are used. Once 'known' your shift you make your correction yourself. For example you add 6 ° for your freezer, you will be less far from the truth .
A+

[Did67]

Agrees.

As it is electronic, we are all convinced that it is super-precise because super-modern ...

Second point: it also depends a lot on where the probes are placed. Ex: I also have a big difference on my solar panel, between the "top of the panel" probe and the (mechanical) thermometer placed on the circuit near the circulator. But the probe goes to the heart of the copper pipe at a T while the thermoeter is placed at the end of a T on the circuit ...

[the middle]

always the same opinion,
So there are measuring devices with a pt 100 temperature probe, with an accuracy of 2%, if memory serves.

[Chaboum]

I agree with you !! accuracy of thermometers, electronics .... on the other hand if I have a difference in T °, ​​it should be constant, right?
- if the probe is not correctly calibrated then this difference will be the same all the time.
- if the probe is positioned in a certain place: it will always be there, therefore constant deviation
that's where I don't see the why.
the difference in T ° between my T ° probe on the solar panel and my probe on the pipe that enters the balloon can be
- 0 ° sometimes 10 ° less and sometimes 20 ° less (this is normal ??) suddenly as the circulation must be cut when the entry T ° is 2 ° above the T ° of the water in the balloon ... well it cuts !!!!! while the panel T ° can be 10 ° higher or even 20 °. See where I'm coming from ??? and if it were constant, we would put a correction value, but no !!! it changes ....

[Flytox]

When a probe is dead it can say anything. This can be seen if it makes large 'leaps' in temperature in a second for example. (Not compatible with the regular flow of water in the pipe.)

If in your pipe you have air / gas instead of water at times, it can also do weird stuff, but it must be understood.

[Chaboum]

it is for this reason that I come to wonder if a phenomenon of ..... electromagnetism, sipritism, trucmuch bidul thing ..... waves trick ..... exists ?? qq something in my environment that would disrupt all that ???? whether it happened to someone or not ...

because it's for all of my measuring instruments in this room,

and nobody has ever seen that !! a freezer which displays -18 ° and which makes -24 ° nobody has ever seen !! I'm the first !! and I surprise everyone ...

well we don't see. or well the probes must not be very accurate

6 ° difference !! I want 1 °, 2 °,

suddenly it is for what the display clearly visible above the freezer door which says -18 ° if there was such a big difference it would be known anyway !! they would change something in the system no !!!!


so this phenomenon ?? unique to me ??

[Christophe]

Uh +1 with remark from Flytox

Have you checked the ... batteries? It counts a lot ... in measurement errors.

What exactly are you using as probes?

In fact nothing beats "mechanical" probes (including mercury) as we do more (or almost) but in some cases it is not easy to use them ...

Personal annecdote: recently I tried to take "precise" measurements at 1/10 ° C with "pro" gear (differential electronic thermometer on K probes) ...

Well it's almost IMPOSSIBLE to have 2 times the same measurement within a few seconds (style you do an ON / OFF / ON and measurements = different) !! Well the errors were around 0.5 ° C but when you buy gear at 1/10 to € 100 you expect to have more precision than 1/2 ° C ...

I was measuring the T ° of copper pipes connected to a circulator: on the k probes (not jacketed) there is electrical disturbance because the measurements were different when the circulator started! This might explain that ?

[Chaboum]

no battery! all the electronic probes are connected to their system (solar water heater, boiler, freezer) and me when I measure (only for my boiler for the outside temperature or room temperature, and for my freezer) I do it with a mercury thermometer .
for the solar water heater: deviations which vary from 60 ° to 50 ° in qq seconds (10 seconds) but which do not go up, which go downhill to stabilize around 48 ° eg.

what I mean is that I don't have a probe that makes the yoyo go down and down, weird value no no, a value that goes down gradually, and which reaches a level that is not in line with the other probe: that of the panel.

basically: it is hot on the panel, the regul tells the pump to start. the water arrives in the tank, it is measured by another probe which starts at the same value of the panel then descends in qq seconds to reach a too low T ° which says to the regul: T ° too low to heat the tank = stop of pumps.

yes it is ????

[Flytox]

Take an interest in all the displays of "measures" that you can see around you in everyday life. There are many who have errors of more than 10%.

The digital display makes it richer, eliminates the reading error but not the measurement error of the electronics behind it. If behind the electronic assembly is very basic, you are in no way sheltered from electronic drifts / components / probes. In the general case this material is set quickly, just to be within the manufacturer's (broad) tolerance and only once in new .... in the end after a few times / years, this can display anything. Somewhere this is normal, they are indicating devices and not regularly calibrated measuring instruments.