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🖥️ActiveHome Pro => ActiveHome Pro General => Wish List => Topic started by: Mal on August 21, 2008, 12:30:20 AM

Title: Thermostat control .. the best and how?
Post by: Mal on August 21, 2008, 12:30:20 AM
Hi: So as a "Newbie" I'm asking the obvious question about if it is possible, and the best way, to control the thermostat?
Seems an obvious thing for home automation, and I don;t mind buying a new thermostat - but which one for a 2-wire system.
By the way, I wouldn't mind an device that could transmit the temperature in each room, at least that way I might find out if things are not working properly.
Best regards to all, and thanks for reading my first, "Newbie", efforts
Good night. Mal.
Title: Re: Thermostat control .. the best and how?
Post by: Boiler on August 21, 2008, 06:12:21 PM
Mal,

First and foremost, welcome to the forum.  We were all newbies at one time.

Now that the pleasantries are over, I afraid that I will be raining on your parade.

Thermostats that can be interfaced to an automation system are typically:

A) 4 to 8 wire systems - you mentioned 2-wire, is this a Heat only application?
B) Expensive : RCS X10 Thermostat (http://www.homecontrols.com/cgi-bin/main/co_disp/displ/carfnbr/219/prrfnbr/1955/RCS-X10-Thermostat-Bi-Directional)
C) Typically designed for use in a large Zoned system (controllable dampers control heating/cooling to different areas ).
D) Expensive (do I need to add a E?).

I'm sorry to dump more, but there isn't a home control technology that I know of that I would trust to "control" the furnace/AC in my home.  Certain things I will only trust to dedicated, hardwired controllers.  I do not want to come home in January to find a frost on the inside of the windows. 

At this point I must ask what you are trying to achieve:
A) Fixing an existing hot/cold location in your home (within limits)?
B) Scheduling ease (easy programming of day/time schedules in a setback style thermostat)?
C) Energy savings
D) Temperature monitoring (not control)

There are methods for addressing the above.  Please give us a better idea of your end goal.

Boiler




Hi: So as a "Newbie" I'm asking the obvious question about if it is possible, and the best way, to control the thermostat?
Seems an obvious thing for home automation, and I don;t mind buying a new thermostat - but which one for a 2-wire system.
By the way, I wouldn't mind an device that could transmit the temperature in each room, at least that way I might find out if things are not working properly.
Best regards to all, and thanks for reading my first, "Newbie", efforts
Good night. Mal.
Title: Re: Thermostat control .. the best and how?
Post by: JeffVolp on August 21, 2008, 07:52:56 PM
I'm sorry to dump more, but there isn't a home control technology that I know of that I would trust to "control" the furnace/AC in my home.  Certain things I will only trust to dedicated, hardwired controllers...

I agree with you.  We opted for the 8-zone Bryant Zone Perfect system here.  The Ocelot handles some supplemental ventilation, and shuts down ducts to unused areas during the night.

Jeff
Title: Re: Thermostat control .. the best and how?
Post by: dave w on August 21, 2008, 09:38:26 PM
Mal
A relatively simple and reliable form of thermostat control is to use two thermostats installed side by side. One would be set to the "normal" temperature and one would be set to a "set-back" temperature.  A DPDT or 4PDT relay with 120VAC coil, controlled by an Appliance Module is used to switch between Normal and Setback thermostats.  Jeff and Boiler are correct in saying that "we" are not comfortable enough with X10 signal reliability to rely on X10 for complete control. But in the "Normal" / "Setback" scenario, even if the X10 signal never went through, the worst to happen would be the house remaining in either the normal or the setback mode. I also controlled the on/off and fan, on our HVAC in the summer but locked out the X10 "on/off" control in the winter to ensure the heat would never accidentally be turned off.

Search this forum for "thermostat" and "HVAC" because I (and others) have provided sufficient details to allow minimal X10 control of HVAC systems. You need to have a little DIY electronic and soldering experience to build the interfaces (mainly just soldering wires to relays). If you are further interested, back in 1994 I wrote several DIY articles for the defunct magazine "Popular Home Automation" and X10 HVAC was one.  PM me with an email address and I will email them to you.   >!