I've attached a new diagram. It's cleaner, and looks better. I have changed the relay. The specs for the relay are Operating voltage 20.4vac, 2.4vac OFF, 24vac rated voltage.
The relay is : 655-K10P-11AT1-24
http://www.mouser.com/ProductDetail/TE-Connec...ty/K10P-11AT1-24/?qs=W847AxTQu3I/bO6G+L/iDA==Data Sheet for the Relay : 655-K10P-11AT1-24
http://www.mouser.com/ds/2/418/NG_DS_1308242_K10_0413-712049.pdfThe Transformer : 655-4000-01E07K999
http://www.mouser.com/ProductDetail/TE-Connec...y/4000-01E07K999/?qs=1eQvB6Dk1vjrX3lMNrzltQ==My voltage coming from the wall is measured at 119.6vac using a 6000 counts DMM, UNI-T
I don't understand what you mean by fixed wiring.. Most of the stuff will be put into an enclosure that will house most of everything. The outlet will be on the outside, mounted to the enclosure.
I honestly don't know if R on the thermostat needs exactly 24vac, but if my boiler downstairs is running on the same electricity, then the transformer supplying 24vac isn't 24vac, because I've measured the voltage up on the third floor and it's 119.6vac. I've heard of others making this thermostat controlled outlet, and they've supplied 28vac to it.. might be bad, but it's not below 24vac. I'm pretty sure it should be fine, but I just tried checking online for answers if R on the thermostat needs an exact 24vac, but so far, I can't find any information. My voltage will be off by only 0.4vac, I honestly don't think it should be a problem.