[Hai-users] Temp sensors accuracy again.
Jim Willeke
jim at willeke.com
Sun Jan 15 03:35:10 CST 2006
I have never seen a single room, let alone a house or a movie theater,
that the HVAC could maintain 1-2 degree temperature through out the room.
And likewise, changes of 10-15% in humidity throughout a home would be
normal. (Basements vs top floors and kitchens/bathrooms vs bedrooms)
Anyone talking of having all thermostats within 1-2 degree readings
throughout a home (or building) has a inaccurate view of reality.
Most "normal" thermostats accept a 5 degree differential for from for
on/off conditions.
Differences of comfort is largely related to activity. So differing
conditions in the Bedroom vs the workout room should be expected. The
ASHRAE Standard 55-1992, "Thermal Environmental Conditions for Human
Occupancy is the standard used by the HVAC industry for decisions on
temperature and humidity. (See this calculator
http://www.automationcollege.com/myfacilities/tools/ComfortCalculator.asp)
Generally, Human comfort is very subjective and depends on:
Air factors
Dry bulb temperature
Relative humidity
Environmental factors
Air movement
Mean Radiant temperature
Personal factors
Activity (metabolic rate)
Clothing
-jim
Brad wrote:
>
> Well in my case, similar to what others have already said, when you
> have temp & humidity sensors each reading all over the map, it makes
> the customer question my credibility and HAI's credibility. Its all
> installed as a system, not they question the entire "expensive"
> systems reliability.
>
> This latest install was in a movie theatre. 1 or 2 degrees off can
> make the difference between customer complaints and not.
> We are talking about folks that are setting inactive for 2-3 hours at
> a time. They notice the difference. Especially the female persuasion.
> They are much more sensitive to temp swings. Then of course you get
> into the humidity. We all know how humidity affects the comfort "feel".
>
> I of yet have not had the chance to put instruments in place long term
> to track the inaccuracies, but I will this week.
>
> As an installer, when I install products I expect them to work as they
> are "perceived" that they should. The customer has the right to expect
> this as well. HAI has excellent products for the most part, but by far
> the temp/humidity sensors and Web-link are sore points in their
> product lineup. When I install a system, it is not fair to the
> customer for me to have to figure in labor cost for "futzing with it
> time" to get things to work as they should.
>
> I'm the anal retentive type, and I have this odd trait that I expect
> things I purchase to work as advertised. Not sorta maybe kinda work as
> advertised.
>
> If you bought a clock and it lost 3 minutes per day, everyday I don't
> think you would keep it very long.
>
> I for one will stop recommending HAI's temp/humidity sensors to anyone
> until they can get the issues cured. It's not rocket science.
>
>
>
>
>
> ------------------------------------------------------------------------
>
> *From:* hai-users-bounces at tssi.com [mailto:hai-users-bounces at tssi.com]
> *On Behalf Of *Brett Griffin
> *Sent:* Saturday, January 14, 2006 12:46 AM
> *To:* 'Ken Schumm'
> *Cc:* hai-users at tssi.com
> *Subject:* RE: [Hai-users] Temp sensors accuracy again.
>
>
>
> Ok, so I have read this conversation many times over the years, and
> have heard different explanations. I have some questions, please take
> a moment to read and don't get annoyed that I take a defensive stance,
> I am really trying to create a good dialogue, and maybe HAI will read
> this and make adjustments.
>
>
>
> My few questions, What is everyone doing with these temperature
> sensors that you need .1% accuracy? You cannot program the HAI system
> to respond to decimal levels. So your programs have a 1 degree
> accuracy, and realistically thinking a 2 degree accuracy since you
> cannot and should not write a two direction program with the temps
> setting closer than 2 degrees.
>
>
>
> I have an OP2, and I had about 4 temp and humidity sensors hooked up
> to the system prior to my move to my new residence. I used them for
> outside temp, and curious things like the temp inside my controller,
> my basement, and my second floor. I could care less if the temp
> outside was 14 degrees or 18 degrees, regardless I had to dress warm.
>
>
>
> Not I understand that there are some more critical things like
> humidors and wine cellars, but even the accuracy is not going to make
> a overall difference.
>
>
>
> The point of the temperature sensor being next to the thermostat, I
> can understand the frustration that they are off by a couple of
> degrees. However taking the safe assumption that the error likely
> tracks over the temperature range (i.e. your home temps swing about 25
> degrees for extremes) why not just adjust the thermostats to match the
> temp sensor.
>
>
>
> The same being true for humidity. What are you guys doing that
> requires such high accuracy in your home? The application I have run
> are like turning the bathroom fan on while taking a shower. The
> humidity will climb close to 100% so I write rules that if it exceeds
> 70% turn the fan on. If you have an air conditioned home, your
> humidity levels will swing between 30-45% Much beyond those levels
> you got problems like static electricity build up and mold. Again I
> don't see an application that requires such high accuracy.
>
>
>
> Now I understand the concerns of what's expected and what's reflected
> are not the same thing and that is a legitimate complaint.
>
>
>
> Now to my next question, I am done Ranting, now I am pondering...
>
>
>
> If you could buy a $20 radio shack sensor and make it work with the
> HAI system, would you buy them over the $80 temp sensor? What if the
> accuracy was +/- 2 degrees. Would you buy one for general use like I
> do, and buy the higher accuracy ones for humidors and wine cellars,
> where the accuracy was more critical?
>
>
>
> Just trying to get insight to your concerns, and by now means do I
> intend to derate your complaints.
>
>
>
> Brett Griffin
> Architechtronics
> www.architechtronics.com <http://www.architechtronics.com/>
>
>
>
>
>
> ------------------------------------------------------------------------
>
> *From:* Brad [mailto:looney2ns at sigecom.net]
> *Sent:* Friday, January 13, 2006 5:46 PM
> *To:* 'Ken Schumm'
> *Cc:* hai-users at tssi.com
> *Subject:* RE: [Hai-users] Temp sensors accuracy again.
>
> Thanks for the replies Ken. Your explanation makes lots of sense.
> Hadn't thought of the wire length issue.
>
> I'm comparing the readings to a $300 Kestrel 4100 Pocket HVAC tool.
> Its temp specs are +/- 1.8 degrees.
> Humidity specs are +/- 3%
>
> I also have 3 of the Radio Shack gauges, and those and the Kestrel
> agrees with each other within a few tenths of each other on temp
> and Humidity.
>
>
>
>
>
> ------------------------------------------------------------------------
>
> *From:* hai-users-bounces at tssi.com
> [mailto:hai-users-bounces at tssi.com] *On Behalf Of *Ken Schumm
> *Sent:* Friday, January 13, 2006 4:59 PM
> *To:* Brad
> *Cc:* hai-users at tssi.com
> *Subject:* Re: [Hai-users] Temp sensors accuracy again.
>
>
>
> Just curious, if your humidity readings are off what are you
> comparing them to? I believe the Radio Shack humidity sensor is
> accurate to +/- 5 %. If the HAI is also +/- 5% the difference
> between the two could be 10% and they'd be within specs.
>
> ----- Original Message -----
>
> *From:* Brad <mailto:looney2ns at sigecom.net>
>
> *To:* 'Wenzel, Guy' <mailto:Guy.Wenzel at capella.edu>
>
> *Cc:* hai-users at tssi.com <mailto:hai-users at tssi.com>
>
> *Sent:* Friday, January 13, 2006 2:00 PM
>
> *Subject:* RE: [Hai-users] Temp sensors accuracy again.
>
>
>
> In my case, the thermostats readings are very accurate; it is
> the Temp.Humid sensor's that are off.
>
> The new temp/humid sensors can not be calibrated. The
> Thermostats can be if needed.
>
>
>
> ------------------------------------------------------------------------
>
> *From:* Wenzel, Guy [mailto:Guy.Wenzel at capella.edu]
> *Sent:* Friday, January 13, 2006 12:40 PM
> *To:* Brad
> *Cc:* hai-users at tssi.com <mailto:hai-users at tssi.com>
> *Subject:* RE: [Hai-users] Temp sensors accuracy again.
>
>
>
> I have a similar setup with an Omnistat and a Temp sensor in
> the hallway near the same room and see the same 3 - 5 degree
> difference. I have not cheeked to see which is more correct.
> Does anyone else know if it can be adjusted or just the
> thermostat?
>
>
>
>
>
> ------------------------------------------------------------------------
>
> *From:* hai-users-bounces at tssi.com
> [mailto:hai-users-bounces at tssi.com] *On Behalf Of *Brad
> *Sent:* Friday, January 13, 2006 12:19 PM
> *To:* hai-users at tssi.com
> *Subject:* [Hai-users] Temp sensors accuracy again.
>
> Just installed 3 HAI temp/humidity sensors. Also installed 3
> HAI OmniStats with remote temp sensors. The Thermostat remote
> sensors and the Temp/Humidity sensors are mounted on inside
> walls within 6 inches of each other, each set in a different
> room. Temp/Humidity sensors show temps being 3-5 degrees
> higher than the thermostats show.
>
> Apparently HAI STILL has not resolved the issue of the
> Temp/Humid sensor's being inaccurate.
>
> The Humidity is reading low on them as well. Very frustrating.
>
> Anyone else seeing this?
>
> ------------------------------------------------------------------------
>
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