Building an automated home is sometimes harder than it *should* be
By john on Jun 2, 2008 in Home Automation, featured
I wrote last week about the new home automation gear I’m installing in my new house – remote controllable light switches, a programmable and remote controllable thermostat, etc. Most of the new gear came in this weekend (they actually did a Saturday delivery – awesome!) and I got time to play with a little bit of it.
First, the good news – the KeypadLinc V2 dimmer from Smart Home works great and was dead simple to install. It installs just like a normal light switch, and was simple to sync up with my Indigo home control server. All in all, it took about 10 minutes to swap it out with the X10 dimmer switch I installed last week (the KeypadLinc is in the master suite). Once I have time to program it (I’ll start that this week, and finish once I’ve got the automation stuff set up house wide) It’ll be able to control my bedroom light, as well as four different “scenes”, which can control any lights / appliances in my house with the push of a button.
The other item I played with was the Venstar T1700 thermostat with an Insteon module for remote control. I unpackaged it and read the instructions – it helpfully gave me wiring diagrams and a table to indicate what wires on the old thermostat would correspond to on the new thermostat. Very cool. I shut off power to the HVAC system and removed the old thermostat, being careful to write down what wires went to which terminals (turns out they were color coded – G was the green wire, Y was the yellow wire and W was the white wire, RC ( R on the new thermostat) was conveniently red). I rewired the new thermostat with the wiring and noticed something – there was no C wire, which the new thermostat requires for power. There WERE plenty (3, maybe 4) unused wires from the old thermostat, but which would be the C wire? I looked online, and found various answers. One suggested that the black wire would be the C Wire (C Wire, for those wondering, is the common wire – a 24volt VAC wire from the furnace – or air handler, most of the time that’s the furnace – to supply power to some programmable thermostats). I tried the black wire, and no dice. In fact, none of the wires worked. Frustrated, I searched more online and found a post with pictures of the FURNACE end of a thermostat wiring job, so I went to the furnace and popped open the access hatch. Sure enough, there was the other end of the wiring, and only one wire was hooked up to the C terminal – a white wire that runs out to the A/C condenser unit. There were, as on the thermostat end, a few unused wires coming from the wire bundle, but something was strange about it…. for starters, there was no black wire like on the thermostat end. The other wires, also, were different – not different COLORS, but different SHADES – one end had light blue, the other dark blue. One light green, the other dark green. In short – they were different bundles. Yet, they had to be connected SOMEHOW, as the old thermostat worked just fine. I figured they must be spliced together somewhere in between the furnace and the thermostat, and continued with what I was doing – hooking up the unused blue wire to the C terminal, closing everything up and heading back to the thermostat and doing the same there. Then, the moment of truth – I went and flipped power back on and……. nothing. Still no power!
At this point I gave up and reinstalled the old thermostat (works fine), vowing to figure this problem out eventually – but knowing that 1230am was probably not the time to keep trying.
It would appear (though I don’t know for sure) that someone spliced two different wire bundles together, except instead of hooking up ALL of the wires in the bundle, they only spliced the ones they were using (lazy SOB), so any future expansion – while LOOKING possible, really isn’t. There were a few other unused wires that I could TRY hooking up to the C terminal on both ends, but something tells me this would be futile. I may try it anyways, just to make sure, though.
Anybody who has thoughts or suggestions on this – by all means please leave a comment and let me know!
As an aside – and mostly off topic – anybody looking to buy a weed trimmer / edger, you would probably be wise to avoid buying a Troy Bilt 4 Cycle gas powered one. I bought one this weekend and had to return it because it wouldn’t start. I exchanged it for another one (same model) that also wouldn’t start, and had a giant crack through the plastic housing surrounding the engine. I’ve read plenty of negative reviews about Troy Bilt equipment – enough to make me take that one back and pick up a black and decker cordless 18 volt electric trimmer. Just an FYI for those who may be in the market for those things this spring / summer.
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An update on this for anyone reading it:
An electrical engineer friend of mine mentioned a way I could test to see which (if any) of the spare wires to the thermostat go all the way through.
After making sure no current is running through them, short the wires on one end (say, at the furnace). Then, using a multimeter set to short (or continuity) mode, test the wires to see which ones go all the way through.
The other option I’m looking at (and almost appeals to me more, to be honest – for a variety of reasons) is running new wiring for the thermostat and installing it in a different location. I have a location in mind that would have easy access for me without having to run the wiring THROUGH walls, and without it being exposed to people. It would also place the thermostat into the main room of the house and get it out from behind the entertainment center (where the current one is), avoiding the heat buildup from the equipment there (and avoiding having the system start up when it doesn’t need to).
john | Jun 5, 2008 | Reply