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[Skidad89]

I saw some dated threads, but, can anyone explain the proper set-up for wiring in the nest thermostat for a auxiliary source such as the wood boiler.  I have it working now, set up as a heat pump but would like to control the backup source (gas heater) a little better by setting a low temp for it to kick on if I forget to put wood in one night 

[Boydz]

Dig into the Emergency Heat or the Duel Fuel options. The EM heat allows you to specify the setpoint. I am still fooling with mine but it is working. I have an issue though where my Heat exchanger is on the return and the furnace gets crabby when seeing warm air above ambient. So unless the Boiler water is completely cool, the controls buck at the back up heat source sometimes. i havent had much of an issue though since i always remember to feed the beast.
I sure do like the nest for tracking and remote control though. Pretty awesome.
Good luck !!

[Skidad89]

Boyd's, thanks for your input. I understand your comments and appear to be set up same as you. I haven't run it long enough or been in the situation where the plenum is too hot for the furnace flame to kick on. Do you remember if you hooked fan to W1 (wood) and the furnace flame to W2/Aux. also, I wish I could program the emergency point higher on the Nest.  I think a little adjustable programming on Nest's part to up the heat pump / emergency heat limit to say 60 or 65 would help.  Also, the nest is a great tool for the wood furnace as I can monitor and adjust heat while away saving wood

[Boydz]

yes - W1 for the wood and W2/Aux for the propane for me. I cant remember how i setup the controller though. I had to mess with it a few different ways and its still not perfect, but i thinks that my HE location causing the issue still because when its cold it works fine. I do remember digging thru the Nest archives and coming across some helpful documents. I also changed my W1 to electric to ditch the cool down which actually was them overshooting the set point.
Anyhow, its doable, keep messing with it

And yeah, Im always logging in remote on my iPhone jacking with it trying to rack up those nest energy saver leaves. LOL
Next stop - converting my old iPhone to a camera for monitoring the boiler remotely on the cheap. I have it working but need to get it in place.
Im a geek like most of us here.

[FareNorth]

Know this is an old thread about using a NEST thermostat.

Recently installed a wood boiler and now looking to tackle the thermostat. Embarrassingly I admit I am just pushing the button on a relay on my oil burner that activates the fan. Looking for a possible way to utilize this thermostat for fan only or if I should add a second NEST for the fan and leave the original thermostat as a backup using the oil burner.

Ideas and pictures if you got em are appreciated. Digging into areas I am unfamiliar with, so hesitate to start hacking wires without some knowledge on my end.

[concordprof]

I'm bumping this old thread for any new information about wiring a Nest thermostat to use both the wood burner and a heat pump as back up heat. Any information will be appreciated.

[mlappin]

Cute thermostat, kinda spendy though.

We have our old style programmable set up pretty easy, 72 when we get out of bed, 67 when we are sleeping, wife is home all the time anyways so daytime temps never change.

Wonder if there is something similar with a programmable secondary thats a little more wallet friendly.

[concordprof]

I misspoke. I actually have a Honeywell version. Some with an hvac guy and they were saying something about a relay???

[mlappin]

Installed a Nest and a Nest Protect as our old smoke alarm was older than dirt.

The wife loves the large display and easy setting as sometimes she would adjust the wrong thermostat when we had two.

At the moment I have the fan on the furnace hooked to W1 and the standard White wire hooked to W2.

I’d like to figure out how to fool it into thinking I have a heat pump so it will only use gas in a dire emergency as this is adjustable in Heat Pump Balance as I don’t find any settings as how to adjust two stage heating.

Also gonna give it a shot on running the whole house humidifier but need a 24volt relay to close the signal loop on the S2020.

I have the first stage set as geothermal, the second is electric.

I’m pretty sure I’ll need another relay or two to fool it into thinking I have a heat pump and the hookups are different as well. When set for heat pump Y1 is still the compressor but it also wants to turn on with the heat, I’m thinking use the O/B terminal for running the AC compressor and set it as a “O” style hookup. O is energized to cool, then the gas furnace can be hooked to W1 which is Auxillary heat. I need to double check if when on heat pump if G is still energized, if so no need to mess around anymore there or G and Y could be hooked together.

I also have a rather unique setup, we had a wood furnace in the basement years ago before building my first OWB. Being a union sheetmetal guy dad had it hooked into the cold air duct for the supply and piped the hot into the original hot air plenum. Have backdraft dampers in both systems so one can’t back feed the other. When I got my first boiler made and hooked up we removed the wood furnace, made up a new piece of duct and placed the water to air exchanger in that so I’m messing around with two different fans, wasn’t a problem wit two different thermostats but is challenging fooling one into controlling everything. Was also easier with two as if several hours after a call for heat in the morning the temp wasn’t up yet then the second one would kick on the gas furnace.

Also get to deal with the whole house humidifier as well, now if the humidifier is calling for air and the OWB is supplying heat the fan in the gas furnace doesn’t run, soon as the fan for the OWB kicks off the fan on the gas furnace kicks in.

Have all the stuff to change a few things around, was never satisfied with the amount of air coming thru the heat exchanger, try to change pulleys and speed it up then it gets noisy, have gone thru the hassle of changing fans to another belt drive and same story. Gonna keep the belt drive in place but move the heat exchanger to the gas furnace and just let the belt drive handle the air flow when the humidifier is calling for a fan but we have no need for heat. The wife always complained before that it felt drafty with the gas furnace fan running just for the humidifier.