To all the HVAC guys who know what their doing

[BiggDogg]

I read a recent thread and it seemed like a number of you fellow 3 wheelers are in the plumbing and HVAC business. so here is a fairly simple question that I can't solve

I have been trying to install a wifi thermostat. I have it hooked up and programmable works but the wifi part is still messed up. it requires a "C" wire for wifi power, so I set up the "C" wire and it works until the furnace kicks in and then it resets my wireless thermostat signal and I lose wifi connection until I reset the thermostat (in other words it stops working once furnace cuts on to heat house, thus making wifi useless).

I read that the "C" wire can't be sharing any other voltage but my electrician says that shouldn't be true.Curently the "C" wire is connected to a white wire above my furnace, that connection also has another wire hooked into it for my water heater. So what is a fix? Should i just go to home depot, buy a new "C" wire and hook it into a separate power source and run it to my thermostat? is that possible, will I short anything?

I don't have A/C in my house
Thermostat is a Filtrete 3M50
house is steam radiators so I guess that makes my furnace a boiler (gas)

[Dirtcrasher]

I am not familiar with how your setup is suppose to be wired, I can just share this.

Take for instance a heating/cooling system that runs both. Each system has it's own 24V transformer with C or a common. Most T stats are just a switch, they have no need for 24V to work, just 2 wires (more if cooling from same stat), they work based on temp rise or fall depending on what season your in. They have batteries for a display. That is why there is an RH and RC terminal that are normally combined. You can run 2 transformers by removing the link from RC to RH or the jumper sometimes which is flipped around. The transformers cannot "buck".

If your wifi needs it's own 24V power source then you may need to isolate it and it's outputs I imagine run the stat. Your not low on amperage, all this stuff is low amperage, your back-feeding something.

R or red is hot 24V - for heating RH or cooling RC
C (usually the black wire if not used, sometimes the blue if not a Carrier system as blue is cooling) is common 24V
W or white is for heat.
Y or yellow is for cooling.
G or green is for the fan motor.

Somehow, I'm not sure you have it hooked up right. Regardless of whether you are in cooling (need a fan wire and a wire to run the air handler and condenser) or heating, any additional wire is for common.

Show me some wiring diagrams, show me the type of stat, one boiler only? or also an air handler for cooling on the same stat?

[Thorpe]

Agreed with DC...

[twitch101]

scan the wiring diag and a close up high res picture of your stat wiring.

[riverrat]

Dirtcrasher is correct. The "c" wire is the common wire from the transformer. The installation instructions for your t-stat state that it must have a dedicated transformer for using the wi-fi. Most likely because rf (radio frequency) can be transmitted through the wires that can interfere with the wi-fi, or the wi-fi is sensitive and cannot have any fluctuation in voltage. Also make sure you are not mixing up the hot and common wires off the transformer. Like dirt said, you could be backfeeding the t-stat.
He stated he didn't have AC dirtcrasher.

Um wait, what kind of water heater do you have? Did they just hook the "c" wire to 110v common? The "c" wire needs to go to the common side of the 24vac transformer, the white wire. Also make sure the transformer is wired correctly to the line voltage. Where is the red wire going to on the boiler? Tell us what boiler you have also.