Omnistat 2

[nexus99]

I am getting myself ready to install an Omnistat 2. (As soon as I work up the fortitude to go back in the attick and start dragging cable in walls again).

Installing one looks pretty straight forward.

If I want to add a second elsewhere do I need to connect it to the HVAC control wiring too or can I just home run it to the HAI panel and the 2nd Omnistat can talk to everything via the panel?

I'm not sure of the proper way to add 2nd and 3rd units.

How do the multiple units deal with temperature settings? Each one has a temp sensor and I am sure there will be different temps in different rooms. If you set one does it set them all? At this point I have a single zone (no dampers or anything fancy) AC + furnace systme (in Socal).

I am just a bit confused how it all works together.

 

[nexus99]

It looks like there is a zigbee version of the Omnistat2 as well. If I have multiples of these units do they just need power somehow and then just connect back to the panel via Zigbee?

 

[jharrell]

Why do you want to add multiple units?

I don't think they integrate like you imagine, a second unit will display temperature where it is installed and control it's own relays. So the only reason for a second unit would be a second HVAC system or perhaps damper control in a zoned system.

If you want to control and display temp in another room then you will need a touchscreen or maybe a console(clunky, bad WAF), or like I do use an iPhone.

If you want it to use temperature on another part of the house for determining HVAC control the you need a indoor remote sensor and the Omnistat will either use it exclusively or average it with it's built in one.

You could technically wire multiple Omnistats in parallel on the HVAC control, but they would be out of sync and it would be possible for one to call for heat and the other cool, I would not think this is recommended.

 

[nexus99]

The things I would like to accomplish with multiple units:

1) Be able to manually change the heat/cool settings from multiple rooms without resortintg to a mobile device
2) Have multiple temp probes across the house (I know I could just add temp probes but the thermostat has them built in too)
3) Eventually use them to control dicreet HVAC zones if I ever get around to installing dampers. It would be awesome to have a zone in the MBR,office, living and then one for everything else.

The HGTV Dream home looked nice... but I imagine that house was using one omnistat2 per HVAC zone.

 

[jharrell]

As far as I know an Omnistat cannot be a "slave" of another Omnistat, so #1 is not really possible, you will need another type of interface to remotely control the Omnistat that runs the HVAC.

I use my old RC80 in the garage for a temperature probe. It displays time, the garage temp and outdoor temp, but it's relays are not hooked to anything, so its just a probe and works well for this, so #2 is covered.

#3 is probably what most people really mean when they think of having multiple thermostats, but from what I understand a properly zoned system is expensive, not easy to do right, and difficult to retrofit. Beyond the multiple Omnistats and dampers you will need some sort of zone controller to arbitrate the multiple thermostats trying to control the HVAC.

 

[ASIHome]

The things I would like to accomplish with multiple units:

1) Be able to manually change the heat/cool settings from multiple rooms without resortintg to a mobile device
2) Have multiple temp probes across the house (I know I could just add temp probes but the thermostat has them built in too)
3) Eventually use them to control dicreet HVAC zones if I ever get around to installing dampers. It would be awesome to have a zone in the MBR,office, living and then one for everything else.

The HGTV Dream home looked nice... but I imagine that house was using one omnistat2 per HVAC zone.

For the second thermostat, you would just tie it to the panel and have the panel change the first thermostat based on what you do on the second.

 

[nexus99]

The things I would like to accomplish with multiple units:

1) Be able to manually change the heat/cool settings from multiple rooms without resortintg to a mobile device
2) Have multiple temp probes across the house (I know I could just add temp probes but the thermostat has them built in too)
3) Eventually use them to control dicreet HVAC zones if I ever get around to installing dampers. It would be awesome to have a zone in the MBR,office, living and then one for everything else.

The HGTV Dream home looked nice... but I imagine that house was using one omnistat2 per HVAC zone.

For the second thermostat, you would just tie it to the panel and have the panel change the first thermostat based on what you do on the second.

Anyone have details of how to integrate Zigbee with the HAI panel so that I wouldn't have to drag wire to the Omnistats?

 

[ASIHome]

Anyone have details of how to integrate Zigbee with the HAI panel so that I wouldn't have to drag wire to the Omnistats?

I am double checking this, but I am pretty sure the ZigBee module and ZigBee OmniStat2's are not shipping yet.

Edit: I got an answer on this, the ZigBee module and OmniStat2's are not expected to be released until later this year.

 

[ASIHome]

It is possible to use a Z-Wave thermostat with an HAI.

 

[nexus99]

Thanks for the info. Looks like I can delay for a while till we know a firm release date for the Zingbee equipment. I am pretty sure this will be required for the integration with the utility meter so might as well wait...

 

[jharrell]

For the second thermostat, you would just tie it to the panel and have the panel change the first thermostat based on what you do on the second.

You would have to write your own programming and I don't think you could really do the act of reading the values from one and setting them to the other?

Maybe 3.0 firmware minimum and even then one programming line per temp value, wow that would be a lot of programming to keep two in sync. Cool and Heat setpoint,fan mode, etc in both directions

EVERY 1 MINUTE IF THERMOSTAT 2 IS 74 THEN THERMOSTAT 1 COOl SETPOINT 74
EVERY 1 MINUTE IF THERMOSTAT 2 IS 75 THEN THERMOSTAT 1 COOl SETPOINT 75
ETC
ETC
ETC

Something like that?