Hello Everyone,
I’m looking at the Touch guide and Circuit image and wonder how this would translate what is used in the U.S.
My heating/cool (no hot water) unit has the following wires:
Thanks,
John
Hello John,
could you find how the cables you named function. A local electrician’s wisdom is needed here to move forward.
There is a good youtube video showing what each wire’s purpose:https://youtu.be/65LE_h76DNc?t=6m44s
Here are text descriptions: (from https://highperformancehvac.com/thermostat-wiring-colors-code/)
Red – The R terminal is the power. This comes from the transformer usually located in the air handler for split systems but you may find the transformer in the condensing unit. For this reason, it is a good idea to kill the power at the condenser and the air handler before changing or working on the wiring at the tstat. If you have a package unit then the transformer is in the package unit.
Red C – The RC terminal is designated for the power for cooling. Some HVAC systems use two transformers. A transformer for cooling and a transformer for heating. In this case, the power from the transformer in the air conditioning system would go to the thermostat terminal. It should be noted that a jumper can be installed between RC and RH for a heating and cooling system equipped with a single transformer.
Red H – The RH terminal is designated for the power for heating. See RC above for an explanation. It should be noted that a jumper can be installed between RC and RH. This is only for heating and cooling systems equipped with a single transformer.
Yellow – This is the terminal for cooling or air conditioning and goes to the compressor relay. Typically a thermostat wire pull is made to the air handler on split systems. This wire is then spliced for the separate wire pull which is made to the condenser. Some manufacturers put a terminal board strip near the control board in the air handler. Therefore, a splice is not needed.
White – This is the terminal for heating. This wire should go directly to the heating source whether it be a gas or oil furnace, electric furnace, or boiler or auxiliary heating for a heat pump.
Green – This is the terminal used for the fan relay to energize the indoor blower fan. On a split system the blower fan is in the air handler. A package unit the blower fan is in the outdoor package unit.
Common (blue or black wire) – This is the terminal which originates from the transformer and is necessary to complete the 24 volts power circuit in the thermostat but only if the thermostat consumes electricity for power. Many digital thermostats require 24 volts for power so the common wire is necessary.
Here is an image of the air handler control board: You can zoom in on the connections. http://www.carrierenterprise.com/rcd-parts-furnace-control-circuit-board-hk42fz027
Thanks,
John
Okay, did my research 
There are some issues we need to address.
First off, HestiaPi is not battery-powered. It is mains-powered and therefore requires 110-230VAC. The 24V AC is not enough. Can you get a power cable where the thermostat is? Even the thinnest should do as HestiaPi consumes very little (draws ~0.1A)
If you can do that, the rest will be easier but you will have to modify the PCB with our guidance.
(Please note there is a bank holiday so you may hear from us after Monday)
Yes I can get a 110VAC line for power.
Thank you for your assistance.
John
Great! Give us a day to prepare the instructions for you.
Hello again,
could you please get a short wire and connect Red ® and White (W). Confirm that the heating turned on. There may be a delay depending on your system before it actually starts.
Then disconnect the wire and connect Red ® and Green (G). Confirm that the fan turns on.
Then disconnect the wire and connect Red ® and Yellow (Y). Confirm that the A/C turns on.
Then disconnect the wire, get an additional wire and connect Red ® with Green (G) and Yellow (Y). Confirm that both the fan and A/C turn on.
During all tests make sure the Red wire does not touch the Blue “common” wire as it will probably blow a fuse.
Let me know of each result.
Thanks for the instructions. I will be able to try it out this weekend and will post results.
John
Thanks guys!! I was wondering all this myself… so once John posts his results I can proceed…
I’m also in need of a case… hint…hint LOL
Hey @cowboysdude how comfortable do you feel about doing these tests too to have a more complete answer?
About the case, the readings are off for 1 degree (actual room temperature is 20’C and HestiaPi shows 21’C). Is this something acceptable for you. We are thinking of running a poll and if most people can live with that we will release the 3D files. Right now we are not happy with this +1 so we keep redesigning the air flow paths inside and outside the case keeping the aesthetics.
I don’t mind doing the tests… is this the test you are talking about? I will be happy to do it but I can do only one as I have heat only and no AC.
could you please get a short wire and connect Red ® and White (W). Confirm that the heating turned on. There may be a delay depending on your system before it actually starts.
Then disconnect the wire and connect Red ® and Green (G). Confirm that the fan turns on.
Then disconnect the wire and connect Red ® and Yellow (Y). Confirm that the A/C turns on.
Then disconnect the wire, get an additional wire and connect Red ® with Green (G) and Yellow (Y). Confirm that both the fan and A/C turn on.
During all tests make sure the Red wire does not touch the Blue “common” wire as it will probably blow a fuse.
Let me know of each result.
Yeap. That is the test. Do you have any idea how common is your setup (no AC) and John’s?
We are thinking of modifying the PCB in the future to support all the 4-5 contacts but this would mean adding 4-5 relays and to be on the safe side they would need to be these big chunky blue boxes that click once triggered, so we are not convinced yet of the feasibility but this would cover an additional, say 50% of the homes then we would need to think about a redesign…
Most have AC honestly. I use window units… until I replace my furnace at which time I will have AC
You could do what some companies do… sell units that only support HEAT and NO AC…that’s how they sell them here because I have never seen any that use the hotwater part… our watertanks are self supporting… they don’t require a thermostat.
I will test it. I just don’t want to burn it up… that’s my only concern and why I’ve waited for this thread to get figured out. BUT I can test it.
How do you turn on hot water though? Is it heated instantly when hot water starts running?
Any update on this?
With apologies… this is my VERY busy time of year. When I get home later I will do the test and report back tonight.
This is the question I have, how do I hook up the power to it? Is it a 110 connection or an RPI plug in adapter? I cannot go any further till I figure out this part…
you only need the 2 wires from mains (L and N), no plug. Strip them and connect them to the terminal block on the HestiaPi main board with the markings L and N. It sits just below the Raspberry’s mini-HDMI port.
Ok. Well I’m going to use a plug because I have an outlet located 2 feet where the current thermostat is now. so whether I use a plug or regular wire 110 is 110 
Ok first… Sorry this taking so long…
I wired the thermostat to power and it’s been sitting like this for a very long time…
My system only uses
Red C – The RC terminal is designated for the power for cooling. Some HVAC systems use two transformers. A transformer for cooling and a transformer for heating. In this case, the power from the transformer in the air conditioning system would go to the thermostat terminal. It should be noted that a jumper can be installed between RC and RH for a heating and cooling system equipped with a single transformer.
Red H – The RH terminal is designated for the power for heating. See RC above for an explanation. It should be noted that a jumper can be installed between RC and RH. This is only for heating and cooling systems equipped with a single transformer.
White – This is the terminal for heating. This wire should go directly to the heating source whether it be a gas or oil furnace, electric furnace, or boiler or auxiliary heating for a heat pump.
I’m pretty sure it’s missing the green wire but mine may be an older system and the furnace control board ‘calls’ the fan to work at temp when it’s needed.
Not sure why it’s setup like that but at any rate…
I tested both and they turn the system on no problems.
So what’s next? 
and just how long does it take to boot this up?
