[Hai-users] Temp sensors accuracy again.

Sun Jan 15 12:03:33 CST 2006

Does anyone have any experience with similar products from other
manufacturers?  I would be interested to know whether a Honeywell
Residential T-stat with outdoor temp exhibits similar characteristics.  I'll
bet they do.  I have some background in HVAC and ASHRAE standards, as well
as how a customers' perception is reality.  I can appreciate all sides of
the comfort discussion, however, the only one that matters is the customer
perception.

I am reluctant to sell the HAI outdoor temperature sensors due to
reliability.  When they work, I've been happy with the relationship between
the reported weather and the reading.  However, for a device that is
designed to be outdoor, we have replaced a very high percentage due to
failure.  Most often it seems related to corrosion.  I digress.

Back to the comfort vs. accuracy discussion and does it matter.  Have you
ever moved into a new home and set the thermostat to a different setting for
the "same" comfort?  Is it due to the different home, different insulation
values, better windows, different t-stat location - or simply the thermostat
reads differently.  Despite the common discussions related to the accuracy
of the temp/humidity sensors, I have never had a customer complain.  If you
are not comfortable, make an adjustment.  People are very familiar with the
concept of a thermostat in their homes.  As for HVAC control for a
commercial application, I would not consider HAI as right of the
application.  I recommend using a recognized controls manufacturer such as
Honeywell or Johnson Controls.

Andrew Comstock
Alarmtech Security Systems, Inc.
519-434-3996 office
519-854-9623 cell

-----Original Message-----
From: hai-users-bounces at tssi.com [mailto:hai-users-bounces at tssi.com] On
Behalf Of Jim Willeke
Sent: Sunday, January 15, 2006 4:35 AM
Cc: hai-users at tssi.com
Subject: Re: [Hai-users] Temp sensors accuracy again.

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 HYPERLINK
"http://www.automationcollege.com/myfacilities/tools/ComfortCalculator.asp"h
ttp://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: 

<!--[if mso 9]--> <!--[endif]--> 

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: HYPERLINK
"mailto:hai-users-bounces at tssi.com"hai-users-bounces at tssi.com [HYPERLINK
"mailto: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: HYPERLINK "mailto:hai-users at tssi.com"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
HYPERLINK "http://www.architechtronics.com/"www.architechtronics.com

   _____  

From: Brad [HYPERLINK
"mailto:looney2ns at sigecom.net"mailto:looney2ns at sigecom.net] 
Sent: Friday, January 13, 2006 5:46 PM
To: 'Ken Schumm'
Cc: HYPERLINK "mailto:hai-users at tssi.com"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: HYPERLINK
"mailto:hai-users-bounces at tssi.com"hai-users-bounces at tssi.com [HYPERLINK
"mailto: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: HYPERLINK "mailto:hai-users at tssi.com"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: HYPERLINK "mailto:looney2ns at sigecom.net"Brad 

To: HYPERLINK "mailto:Guy.Wenzel at capella.edu"'Wenzel, Guy' 

Cc: HYPERLINK "mailto:hai-users at tssi.com"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 [HYPERLINK
"mailto:Guy.Wenzel at capella.edu"mailto:Guy.Wenzel at capella.edu] 
Sent: Friday, January 13, 2006 12:40 PM
To: Brad
Cc: HYPERLINK "mailto:hai-users at tssi.com"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: HYPERLINK
"mailto:hai-users-bounces at tssi.com"hai-users-bounces at tssi.com [HYPERLINK
"mailto: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: HYPERLINK "mailto:hai-users at tssi.com"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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