How do I calibrate pressure?

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  • Updated 3 years ago
I've had a 01512 unit for about three months. The forecast icons have never been close to correct and the pressure trending arrow doesn't move but the pressure reading itself has always been pretty accurate. Today I noticed it was way off - reading 30.06 and pressure is 30.16. I tried to manually adjust. Manual says first hold the set key 10 secs to put in manual mode. Then hold Up Down and Set keys 6 secs to enter calibration mode. If in auto mode I do get to calibration, but in manual mode holding the three keys only sends me back to auto mode, not calibration. How do I calibrate pressure?
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Rich

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Posted 3 years ago

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AcuRite Crystal

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Hi Rich,

To adjust the calibration settings, you will need to press and hold the up arrow button, set button and the down arrow button all at the same time for at least 5 seconds.  This will allow you to adjust the settings from there.  To switch from Manual to Auto, press and hold the set button for 10 seconds.  If you have any further questions, please let us know.
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Rich

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Crystal, thanks for the reply.  I understand the instructions but my unit is not working that way.  I was hoping maybe the manual was misstating something but, apparently, if must just be that my unit is defective.  As I said, after I hold the set button to put it in manual and then the three buttons at once the unit just goes back to Auto not into Calibrate.  Not sure what to do about that.
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AcuRite Crystal

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Hi Rich,

The following instructions should help resolve any issues you are having with your display.


To do a factory reset: (THIS WILL CLEAR ALL OF YOUR HISTORY AND YOUR SETTINGS)


Please verify that you are using a name brand (Rayovac or Energizer) standard alkaline batteries in the display unit. We do not recommend using anything that is heavy duty, rechargeable, store brand or Lithium inside of the display.

- Remove all power, AC adapter and batteries, from the display unit.
- Inside the batter compartment there should be a white sticker with four numbers on it, please email those numbers to me.
- Press and hold down the CLEAR RECORD/RESET button, located in the battery compartment, for 20 seconds.
- Plug back into AC power and insert recommended batteries.
- Press and hold down the CLEAR RECORD/RESET button for an additional 20 seconds.
- Verify that the unit has powered on and once connection has been made, attempt to set time and date.

If this does not resolve the problem, please email me back so that we can work to get this resolved.
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Rich

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As long as I'm on this subject in general, what's up with the icons?  I know they're only meant to be marginally predictive but the only two I get alternate between Rain Likely and Chance of Rain.  I live in Southern CA and rain really hasn't been a factor lately.  The icons I can let slide but the trending arrow should work - it has never budged from horizontal.
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AcuRite Crystal

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Hi Rich,

It could be that with the unit alternating between manual and auto, that it never had the chance to go through a proper learning mode.  I recommend doing the reset above and allowing it to go through the full 14-33 day learning period to properly get a correct barometric pressure reading.
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Rich

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OK, I'll try it.  The number on the sticker inside the battery compartment is QC 4114
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AcuRite Kevin

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Rich,

Be sure to let us know if we can be of further assistance.  Have a great day!
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Rich

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OK, thanks.  I did the factory reset that Crystal suggested and I'm back in learning mode.  The pressure is still reading about 0.1 inHg low but I will give it a chance to learn.  Same with trend arrow - still hasn't moved.  I don't mind calibrating the pressure but I couldn't get into calibration mode doing as instructed both by Crystal and the manual.  We'll see.
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AcuRite Kevin

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Hi Rich,

The accuracy standard for barometric pressure on our units is .15inHg, so your unit is currently within that limit.  Please continue to let the Learning Mode complete. 

Have a great day! 
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Rich

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Really?  That means if the true pressure was 30.00 inHg the unit might read anywhere from 29.85 to 30.15 - which seems like a pretty big range (why even have a read-out with two decimal places) but it could just be that here in Southern CA the pressure never gets much outside of 29.5 to 30.5.  Probably why the icons don't work but the trend arrow does work either.  How much of a pressure change per hour is needed to make the trend arrow move?  Do you have a spec on that?

Anyway, the absolute value of the pressure read-out can be adjusted with a calibration offset, I assume.  That wasn't the problem I originally posted about.  It was because I couldn't get into calibration mode.  I'm going to give the learning period some time, see what happens with the pressure read-out (accuracy notwithstanding, up until a week ago it was pretty dead on in Auto mode and then seemed to spontaneously go off by 0.1 to 0.15 inHg) and then try calibrating again if needed.
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AcuRite Crystal

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Hi Rich,

Here is information on how your 01512 barometric pressure trend arrow should be behaving.

•Pressure
arrows will not change for first three hours after battery inserted.  Pressure readings will
change, but the arrows will not


•After
first three hours, unit
compares current
pressure to measurement taken
three hours
ago.  The arrow will change or stay the same per
the data below – the rate of change in this three hour comparison is what
changes the arrow


•After
that, unit will calculate
once every
hour (from battery insertion) looking back three hours to compare change


•Arrows
change once per hour (from when batteries inserted)                                                                                                                                                                          

•Calculations
are in inHg
(inches of mercury).   0.03 inHg
equals one milibar of
pressure



•Rising
Arrow = change more than +0.09 inHg


•Steady
Arrow = change within +/-0.09 inHG


•Falling
Arrow = change more than -0.09 inHg



If you have any further questions, please let us know.




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Rich

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OK, thanks for that info.  Trend arrow probably is working and, as I said, it's just that we don't usually get pressure swings that large here in Southern CA.
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AcuRite Crystal

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Hi Rich,

No problem, if you have any further questions, please let us know.  Have a great day!