sic0048 said:
Since I have no experience with either the rain8net or dampers, take this with a grain of salt.
But just looking at the thing, I'd have to say that the rain8net should work fine. Afterall, it is simply turning on 24vac power to the proper sprinkler zone when asked to. So you'd think you could send 24vac to the correct damper when asked to. It also looks like the power supply is rated high enough to power two "zones" at the same time, so you could power two different dampers (like the upstairs supply and return damper) and the same time.
Of course you would need to use CQC to turn on the zone and then turn it off. The automatic timer function of the rain8net has no real application in this setting. But it's simple enough to write the logic with CQC based on the temp upstairs vs downstairs and if the HVAC system is currently on.
I have installed the damper control systems, and to be honest even a 6 zone control system is under 300 bucks to buy. You do not have to use all the zones, but it is nice to have a couple extra incase down the road you want your bathroom or other room to stay at one temperature.
What most people do not buy is the barometric damper, that damper allows air, to recirculate from the supply plenum back to the return, if static pressure rises above a certain pressure.
I just did an existing three ton system, and installed a 14 inch bypass damper into the system. It requires some large flex, a large "T", some plastic "P" or zip ties, and a large take off, that you cut into the supply plenum. Then you basically just cut the flex to the registers or diffusers you wish to regulate, add on the power damper, it is just a short piece of round duct that has a damper inside of it. Then you put the flex back on the damper. They also make square dampers as well. I used four round dampers. One fourteen inch round power damper, and three six inch power dampers. The fourteen inch damper feed a 14 inch round duct, that had round take off's cut into that feed the same large room.
Each damper is controlled by its own thermostat. All thermostats in the house go to the damper control panel. As do all the damper wires. Three wires are needed for the PO power open and PC power close dampers. Common, PO and PC.
In a normal state the control panel opens all dampers, as soon as there is a call, it closes all the dampers that are not calling and turns on the air handler. You can turn on the fan, and send air to just the damper that is calling for the fan. You can even turn on the Air Conditioning on one thermostat and the heat on the others. Every fifteen minutes of inactivity from a heating cycle, will give the thermostat calling for AC a chance to run the compressor. To buy the stuff you need, to do something like that you are looking at about $1300.00
But you get outrageously hot air, outrageously cold dry air, because of the bio-metric damper recirculating the air within the unit. The air handler is protected by a heat sensor monitored by the control panel, that limits the temperature in the supply duct, either to hot or to cold. If you are supplying one six inch duct, with 3 tons of AC, you are going to have to shut the compressor down, if there is some strange occurrence that keeps that thermostat calling for air-conditioning.
If done right they are amazing. if done wrong they are horrible.
I have fooled with back feeding thermostats and it can cause problems, sometimes when you back feed a fan terminal on a thermostat it will turn on the Y1 and run the compressor. So I tend to avoid crazy wiring schemes. Unless I have a lot of time to fool around.
You actually need three NO (Normally open), NC (Normally Closed) relays just to isolate, each damper, from each thermostat, and air handler, it is not at all worth it, to try to do it yourself. If you only need two zones the controller is about $100 bucks. And leaves you with an extra zone capability.
The bio-metric damper, that works on gravity, very easy to setup, very simple, is about half the price of the same size power damper. Dampers are about $100 bucks no matter what size they are.
Sincerely,
William McCormick