Hi Well, i guess what would be most useful would be some tables so as to figure heat loss and gain such as they use for buildings.?? For aquariums they generally recommend 1-2 watts for a rise of 5 degrees per gallon. Which would calculate out to around 2000 watts lol My hot water tank only draws 2500. i think the thing to bear in mind is I'm not trying to raise the temp of the water just maintain it. Would think this would be a big difference in wattage required?? In my neck of the woods the all time record low was 27 for 4 hours and the low daytime was 55. We just broke that record Monday with a daytime high of 54 the low was 34 so not a record. I recorded 38-60 in my shadehouse. has frosted 6 times in the last 30 years. Normal winter temps are 65-75 throughout winter with greatest possibility of frost in Feb. Some of the peculiarities of this climate with cold Is the front must push straight south with no wind otherwise the gulfstream heats the air. The sky must be dry and perfectly clear,only way radiation cooling is allowed. Temps below freezing are impossible without all these conditions. Another peculiarity is that at sunrise the radiation heat from the sun is tremendous so if you cover something it quickly cooks lol. 15 to 20 degree raises are common in an hour. So the max in my situation would be 30-35 degrees for around 5 hours MAYBE 1 week a year Any ideas how to figure this out?? i certainly appreciate the help. gary

"I just am not clear on where the extra C-wire gets wired to. " Because the thermostat is electronic, it needs constant 24v - so this is a 'hot' wire right from the transformer. I would wait until Spring to try this :)

Trying to install a new Ecobee3 thermostat and have to run a "Common" wire up to the thermostat. Difficult to find any solid information on the Honeywell Aquastat L8048G online (just for the replacement controllers, which are not wired exactly the same as the L8048G). Attached is a diagram of the current (pre-Ecobee3) wiring (boiler, Taco valves, thermostats) - want to make sure it is correct. I have seen some wiring diagrams that show alternate ways to wire the thermostats and Taco valves, so want to make sure my current wiring is actually correct. It always worked before, but want to make sure nothing is installed incorrectly/backwards. The Aquastat has a built-in 24V transformer. How do I know which wire would be used for the COMMON wire? Assume blue wire on "T" would be the "Common"? If not, which wire/terminal would I use? Assume I can pull a common from the Aquastat board/internal transformer, but not sure. If not, should I purchase a stand-alone 24V transformer or the FAST-STAT Common Maker? http://www.fast-stat.net/ If that is the case, how would I wire one into the current system? Please review the diagram and comment/correct as necessary. The boiler has been seemingly fine for 48 years wired as shown, but see various ways to wire thermostats and valves to boiler and want to make sure it is correct. Most important issue is how to add a common wire to this setup most economically. Thank you for any assistance you can provide.

Do you have any other controls in your heating system? If not there would be no reason why you could not replace this with a wifi thermostat. You also have an additional wire which will have to be utilized and used as you will need a common. If you buy the ecobee they have a tech support that will walk you through wiring and set up of your ecobee at no charge. As mentioned if you have no other controls associated with the existing thermostat it would be a simple fit. Just an FYI the AC unit bears no relevance to your concern as the wiring diagram states this is a simple on off signal sent from your furnace. I hope this helps.