The Great Thermostat Search

[beelzerob]

Fantastic info jkish, thanks. That explains it perfectly. I don't see from the wiring diagrams where the serial adapter goes, but I'm thinking it just takes the place of one of the thermostat @ the 3 wire connectors.

This helps because I was about to pull the trigger on an IAQ on ebay, but now I see I don't need the thermostat with the interface module, I need *just* the thermostat, as the zone controller will take the place of the IM.

Excellent thanks!

 

[jkish]

Fantastic info jkish, thanks. That explains it perfectly. I don't see from the wiring diagrams where the serial adapter goes, but I'm thinking it just takes the place of one of the thermostat @ the 3 wire connectors.

This helps because I was about to pull the trigger on an IAQ on ebay, but now I see I don't need the thermostat with the interface module, I need *just* the thermostat, as the zone controller will take the place of the IM.

Excellent thanks!

Since it is a bus, my guess is that the serial interface could be connected in parallel with any of the other things connected to the Enviracom bus.

The install manual for the serial adapter shows it connected in parallel with an external temp sensor on the bus.

 

[english_1969]

Honeywell's control bus is called Enviracom. The Honeywell Enviracom Serial Adapter- W8735A1005, allows you to connect to the bus via RS232: http://customer.honeywell.com/Honeywell/Pr...aspx/W8735A1005

The CQC driver references can probably be found by searching for Enviracom over there. EDIT - looks like BPH might have been the one with the driver: http://www.charmedquark.com/vb_forum/showthread.php?t=2542

You can buy the thermostat + the interface box (not including serial adapter) pretty cheap via Amazon - http://www.amazon.com/Honeywell-VisionPro-.../ref=pd_sim_k_2 - and even cheaper on eBay

Wow, okay, now we seem to be talking. I have the 9421 unit (x3) and the remote terminal box (x2). I've looked for something to talk to this for a long time now. Shows what the local HVAC contractor knows.

Sounds like I can buy 2 of these serial units and be in the business of controlling my t-stats!

Thanks!!!!!

 

[beelzerob]

Before you get *too* happy about all that, you should take a look at securing the communication protocol doc first. I've been all over the web and could not find the "application level specification" that Honeywell mentions with their serial adapter. Interestingly, the *best* info google had to offer was actually here on cocoontech. But the documents there appear to be just what reverse engineering could reveal, which leaves a lot of "unknowns" throughout, and isnt as extensive as I'll need if Im going to commit to the 9421.

 

[jkish]

Before you get *too* happy about all that, you should take a look at securing the communication protocol doc first. I've been all over the web and could not find the "application level specification" that Honeywell mentions with their serial adapter. Interestingly, the *best* info google had to offer was actually here on cocoontech. But the documents there appear to be just what reverse engineering could reveal, which leaves a lot of "unknowns" throughout, and isnt as extensive as I'll need if Im going to commit to the 9421.

There is an Enviracom SourceForge project: http://sourceforge.net/projects/enviracom/

In there, one of the files appears to be a brief API doc and a C interface written by someone at Honeywell: http://sourceforge.net/projects/enviracom/...pi-orig.tar.gz/

 

[beelzerob]

Ya, C files somewhat implementing the protocol seem to be the closest that can be found. bph over on the cqc forums seemed to indicate he had actually written an enviracom driver (which you linked for me), so Im asking him about that.

The contractor that came out today actually recommended the iaq thermostat and I told him my frustration at not getting the doc, and he said he knew some engineers at honeywell he'd ask about it. Ya right, but we'll see what happens.

 

[jkish]

Ya, C files somewhat implementing the protocol seem to be the closest that can be found. bph over on the cqc forums seemed to indicate he had actually written an enviracom driver (which you linked for me), so Im asking him about that.

The contractor that came out today actually recommended the iaq thermostat and I told him my frustration at not getting the doc, and he said he knew some engineers at honeywell he'd ask about it. Ya right, but we'll see what happens.

One of the nice things about the 9421 is that it is one of the most highly recommended thermostats out there even if you don't want to be able to communicate with it.

The code in the SourceForge project appears to have been written by someone at Honeywell originally which sets it apart from other things I have found. In particular, the h file has extensive commenting on the protocol bits and pieces.

 

[beelzerob]

Huh...well, I've got more than a little C under my belt, so that's as good a source as any. I just have to find a way to gunzip and then untar that file. I'm sure there's a utility for windows somewhere....

 

[english_1969]

Huh...well, I've got more than a little C under my belt, so that's as good a source as any. I just have to find a way to gunzip and then untar that file. I'm sure there's a utility for windows somewhere....

Well, I just bought one of the serial adapters (amazon ~$100) so I will see what I can get to work. Reviewed the sourceforge information and it looks like I should be able to get some basic functionality.

We'll see...

WE

 

[standon]

I have a mix of Honeywell IAQ and Trane thermostats - which look exactly the same, I found this on CQC forums - would it work on your Trane systems?

Trane ComfortlinkII Driver

Edit: I just checked and my thermostats all have Honeywell control panels.

 

[beelzerob]

It's almost crunch time, so I think I've settled on the HAI RC2000 because it does everything I want.

I understand now that there really is no such thing as damper control from an HA perspective. So, I'll simply need to provide the 2 thermostats and the HVAC installer will put in the dampers and the damper controller, and the "need for heat" of a thermostat is what gets translated by the zone controller into which dampers get opened.

Because of that, I may go with an RC2000 for the main thermostat downstairs, which has humidity control, and then a cheaper RC1000 upstairs. We really don't need 2 humidity controllers in the house, I've decided!

 

[signal15]

It's almost crunch time, so I think I've settled on the HAI RC2000 because it does everything I want.

I understand now that there really is no such thing as damper control from an HA perspective. So, I'll simply need to provide the 2 thermostats and the HVAC installer will put in the dampers and the damper controller, and the "need for heat" of a thermostat is what gets translated by the zone controller into which dampers get opened.

Because of that, I may go with an RC2000 for the main thermostat downstairs, which has humidity control, and then a cheaper RC1000 upstairs. We really don't need 2 humidity controllers in the house, I've decided!

Make sure you put the one with humidity control in the area of the house that has the most stuff that could be negatively affected by humidity or lack thereof. Wood floors, grand piano, violin storage, etc.