Ted,
Let me take your last post from the bottom up -
3. I'd like to pull temperature data from the boiler to pull into a computer to see how the system runs. I'm a chemical engineer (that's why you have to explain things slowly to me), and I'm curious how the system performs.
You're being modest. I happen to be a EE that transitioned to ME and then to HME (hydromechanical). Jack of many trades, master of none.
I've never had to explain things slowly to a Chemical Engineer (I have two in the family). Normally they ask me embarrassing questions that cause me to scramble for answers. At my age they are required to ask questions Loudly, Clearly, and Repeat them (gives me time to search the memory archives - this rarely works for me).
Not only are you a Chem-E, you appear to be heavily involved in processes and efficiencies. Possibly a bit of a reach, but you're interested in tuning your system beyond the normal "out of the box" efficiencies".
Past that, I have no experience with monitoring Inlet/Outlet temperatures (efficiencies) with a home automation system. To the best of my knowledge, this is still the domain of dedicated hardwired controllers (thermocouple/thermistor/RTD inputs).
2. Take control of the DHW (domestic hot water). The new boiler will send 180 F hot water to an external tank to heat up DHW to 140 F. I'd like to override the temperature controls and add timers, especially for nightime. I also have teenagers who take unending showers. It would be fun to have a wireless X-10 controller and turn the boiler off after they've been in the "sauna" for awhile.
Man it's great to hear someone with a good sense of humor. I got a good belly laugh out of the teenager ploy. What I assume you're asking for is a X10 compatible gate valve that would shut off the hot water to the "Teenager Shower". While I applaud your sense of "Pavlovian conditioning", I don't know of a off the shelf device that can do this. Most of the electric gate valves that I have seen are 24V and hardwire to a relay panel. Maybe a sprinkler controller (RF of course) would fit the bill?
1. Take more control over the "modulating" function of the boiler. This is a condensing boiler, and will produce lower temperature hot water when it is only a cold outside (say 25 degrees) and then crank the boiler output up to 180 F when it gets below zero outside. I'd like more control over this to see if dropping the boiler water temperature and running the boiler longer would be cheaper than the standard program.
Once again, X10 tends to operate on events (On/Off/Dim). Temperature monitoring and control (proportional) is difficult. To monitor this properly, I believe you would require a dedicated analog to digital board that would communicate with a digital controller (Stargate perhaps). You're really looking for a process controller here.
Those are my thoughts (misguided though they may be),
Boiler