Complex A/C control?

[mitch236]

Now that I have the Venstar thermostat, I was thinking about creating a program to make the a/c more efficient. One of the thermostats controls the second floor of my house. The thermostat is located in the hallway that is a catwalk that connects one side of the second floor to the other side. Each side has two bedrooms. Since the catwalk is located in the main house's airspace, its temp does not reflect the temp in any of the bedrooms. In fact, I have to set the thermostat high because the catwalk is always warmer than the bedrooms. Because of this problem I cannot keep the temps in the bedrooms consistent.

 

Now for my proposal:

 

I am thinking about installing four of these:

8-Inch Diameter Normally Closed Electronic HVAC Air Duct Damper with Power Supply

 

and controlling them with:

24V AC 40VA Power Supply w/Auto-Resetting Fuse

 

 

And controlling the thermostat with four of these, one mounted in each bedroom:

Venstar Wireless Indoor/Outdoor Remote Temperature Sensor

 

 

Then I would write a program to have the a/c turn on when any of the sensors falls above the desired temp for each room and then openning the vent for that or any/all rooms that need it.

 

 

Will this work? I didn't see a specific Insteon temp sensor so I'm not so sure this will integrate properly. Has anyone tried a similar installation? If so, can you post your programming?

 

Thanks!

[garybixler]

mitch236

 

I had bought the remote indoor and outdoor temp sensors for the Venstar, but unfortunately the ISY (Insteon) can't see them at least for now. I have been patiently waiting just to be able to read the outside temp into the Insteon network, but there just doesn't seam to be any way to do that. Indoors I have just added another Venstar thermostat with the Insteon adapter but it won't read below 32 degrees for outdoor use.

I would think being able to easily read temperatures (indoor, outdoor, water, etc.) would be the basics for automation. Maybe soon.

I would be glad to hear if there is a way.

 

Gary

[Michel Kohanim]

Hi Gary,

 

Long time no see! The last time I checked, this property is not query-able via the current protocol specs. I shall send an email to SH to verify.

 

With kind regards,

Michel

[garybixler]

Hi Michel

 

I suspect that the remotes will never be accessible via the insteon module on the Venstar..

 

I am surprised however that SH has not yet come up with Insteon wireless temperature modules that could be used indoors, outdoors and for monitoring water temperatures. Seams like many users have looked for such capabilities. Anyway its on my wish list.

 

btw I am at 2.7.14 with no problems.

Gary

[mitch236]

So basically, it can't be done. I'm amazed there isn't a remote temp sensor that can tie into the Insteon network. I can't imagine it would be difficult to make one.

[Michel Kohanim]

I totally agree ... to more generic, there should be INSTEON analog sensors which can be used for all purposes.

 

With kind regards,

Michel

[garybixler]

mitch

 

I think it could be done with 4 cheap heat/cool mechanical thermostats connected to 4 Insteon I/O Lincs to get the temp set points from each bedroom. Then an I/O Linc to turn on the AC or program set point changes in the Venstar and finally more Insteon relay modules to open close dampers.

Just my thoughts on how it could be possiable.

Gary

[Michel Kohanim]

Hi Gary,

 

Yes, that would be a solution but not ideal since you cannot actually use the analog values coming off the sensor as such you are bound by On/Off based on set temperatures.

 

There has to be analog INSTEON sensors ... I believe this is one thing that is missing from the product line.

 

With kind regards,

Michel

[Goose66]

Simplehomenet has a number of devices (e.g. EZIO8SA) that offer analog inputs with 1024 point resolution. Most of these have relay outputs as well. It seems like one or more of these devices could be used to both read the room temperatures and to control the damplers. I do not know what support for these devices exist in the ISY.

 

However, the solution may be more complicated that you think. First, you probably want dampers on both the vents and the returns. This will substantially increase your cost. But, if you are sending air to only one room but all returns are active, then you create negative pressure situations in the other rooms that will suck air under the doors. This may cause doors to "pop" open, whistling or other air noise, the nasty black stuff on your carpet under the doors, shortened lifetime of your HVAC unit, etc.

 

Further, if you are going to let the ISY control your multizone HVAC over Insteon, I suggest installing a negative pressure damper on a return from the common space (over the catwalk) and as well as a vent over the catwalk. This may mitigate circumstances that could damage your unit, such as the Venstar commanding HVAC to a room but the Insteon signals to the dampers not reaching their destinations. You don't want to have the unit running and all dampers closed! Lots of online dicussions around this. I suggest you read up and let us know what your final design looks like.

[Goose66]

How about two EZIO2X4s connected to temperature-sensing IC-chips (e.g. http://www.smarthome.com/1523/Temperature-Sensing-IC-Chip/p.aspx) mounted in small plastic boxes in each room. If you design a circuit board for these with screw terminals and a .1mf capacitor across the output and ground, order 4 for me as well.

 

Better yet, how much you want to bet that the Venstar remote temperature sensor (http://www.smarthome.com/30421/Venstar-Indoor-Outdoor-Remote-Temperature-Sensor/p.aspx) is not exactly that: a temperature sensing IC-chip mounted to a circuit board in a plastic case that receives a 5V Vs and returns 0-5V signal based on the temperature.

[Goose66]

The problem, though, will be in the ISY programming for such a setup. Ideally you would want the temperature setpoint for each room to be compared to the current reading of the Venstar, which is going to require variables and probably the ability to do some math. In addition, even if the ISY allows access to the current values of the EZIO analog inputs, you are going to have to figure out how to poll for these on a periodic basis.

[Michel Kohanim]

Hi kingwr,

 

Thanks so very much for the feedback ... the main issue is that we cannot guarantee smooth interoperability with SHN devices. I was told that they were going to fix it but have not heard back since.

 

With kind regards,

Michel

[Goose66]

Got it. Perhaps when the SHN issues are ironed out, we can pursue this further, because I have the same issue but have shyed away from overly expensive mutli-zone controllers and systems.

 

However, does the ISY support automatic, periodic polloing of any devices? For example, could the firmware code supporting the EZIO2X4 be written to periodically poll for the value of the analog input and change the state internally (thus potentially triggering a program) if the value changes? It looks like the "alarm value" that can be programmed in the EZIO2X4 only works in one direction.

[Michel Kohanim]

Hi kingwr,

 

You can do that via programs ... the only issue is that the analog input can only be read using i2 and we have yet been able to extract that information!

 

With kind regards,

Michel