DIY Zoning: Total Control
Making the system completely operational
If you made it this far, you definitely know what you are doing. There's just this pesky issue of dealing with real world and its issues. Mostly, these issues boil down to the following quotation:
What we do not understand, we fear. What we fear, we destroy.
Like it says in the prerequisites, if you decide to install the hardware that controls your HVAC unit, and, God forbid, connect it to your HVAC unit, you're looking for trouble. Your HVAC servicemen will look funny at you. They, in turn, may make your home warranty company look funny at you. As well as manufacturer warranty supervisor. As a result, you may lose the warranty on your equipment, and, what's even worse, have an insurance fraud lawsuit against you filed by your home warranty company. So let me repeat again, in bold letters:
Now that we're done with formalities, let's get down to business.
Choosing the right hardware
Depending on the kind of HVAC unit that you have, you may choose to select different hardware to control it. The (known) options are: 1-Wire® serial and USB.
This option uses1-Wire® switches (DS2406 or DS2408) combined with optoisolators and triacs, or a plain relay.
An advantage is low cost, a disadvantage is that they can't really be represented as an integral device, but as a collection of switches.
Custom devices (such as a DTR controller made by Tim Small) as well as existing devices such as X10 fall into this category.
An advantage is that the devices are integral (from the business logic point of view), a disadvantage is that they can't be autoprobed.
There are some nifty USB devices that allow to control high power currents, but none of them seem to be available at the moment.
An advantage is that the devices are integral, a disadvantage is that the USB specs don't allow a cable to be longer than a few meters, so you will either have to place the computer running DZ next to your HVAC unit (which is not entirely unreasonable), or have longer 24VAC wire runs from the HVAC unit to your computer.
Connecting DZ to your HVAC unit
First of all, you have to understand how the HVAC unit is controlled.
A typical thermostat connector looks like this:
|C||Black?||Common. Not a ground!|
|R||Red||Return. 24V AC.|
|B||Blue||Engage heat mode.|
|O||Orange||Engage cool mode.|
|G||Green||Call for fan.|
|Y||Yellow||Call for cool.|
|W||White||Call for heat.|
For multistage units, there will be Y2, W2. Sometimes, there's a HUM input to connect the humidifier. And again, this chart may be completely off if the connector is proprietary, such as Carrier Infinity (just 4 wires, function unknown).
Lo and behold, you've finished the installation. Now, let's try to think outside of the box.
Proceed to Beyond Installation.