Agreed with all the points above. I'm going to inquire as to a few things before they do anything:
1. which thermostat allows full manual programming on device screen (no phone app/internet needed)
2. will they install the "C" wire or some adapter kit or do I need to waste money/time dong it
3. do I keep my old thermostat so I can swap it in in case of an emergency
4. can I run the thermostat "off line" if I choose to (no internet hookup)
Yes I know I am paying for the program indirectly.... Same goes for the "LED light" upgrade that ran through my office twice already. I kept the old halogen bulbs, they installed a bunch of LED each time until all my lights were replaced. If it is not going to be messy, at least I want to get something back from all these levies/subsidies I have been paying to the utility.
I've attached what I believe represents the wiring for my thermostat. I see that the red wire is 24VAC from a transformer, and that the thermostat "bridges" across to the other wires for the fan, furnace or AC to complete the loop and toggle the relay. As long as the relay is activated, there is 24VAC going through the circuit?
I also found this video which explains a few things:
1. Honeywell mentions re-purposing of "G" as the "C" wire
2. Honeywell says it depends on building code (anyone know if this is ok in Toronto?)
3. The video shows jumping the Y and G on the control board
- I presume this is so the fan works when the air-conditioner is on
4. The fan will be automatically activated by the furnace when heating, but not cooling, necessitating the jumper?
I am assuming that the furnace control board manages to handle the fan itself whenever the heat is on, so it doesn't care what signal is coming from the thermostat. But for the A/C, the fan is turned on by the thermostat which should ALWAYS turn both the G and Y relays on whenever cooling is active (or optionally just G when you want fan but no additional compressor A/C). I can't imagine the compressor Y ever being active but not the fan G.... unless there is some "delay" the thermostat introduces to let the compressor start slightly before the fan, or is that not the case?
So by shorting Y and G terminals at the furnace control board, you are essentially sending the 24VAC signal through both Y/G relays at the same time when the A/C is activated, ensuring the fan is going to be on whenever the cooling system is on, correct? But that limits the ability to control the fan independently.... although I have never ever used the fan separately in any case.
I found this to be a good quick learning resource:
https://www.qwik.com/education-and-training/articles/thermostatic-wiring-principlesAnd this was very helpful in answering many of my questions:
https://diy.stackexchange.com/questions/58510/is-there-any-risk-of-running-both-the-fan-and-furnace-at-the-same-time