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6

You don't. There is a feature called Heat*Cool: https://nest.com/support/article/What-is-Heat-Cool-mode


4

I would adjust the dampers so the ones in the smaller rooms are not fully open this will put more flow to the larger room. Things to think about that can reduce flow to a room is the bottom of the door jamb tight to the carpet or floor this can act like a damper once the room is pressurized the flow will be reduced with the damper open. If this is the case ...


3

Which Nest Protect should I get? Just check the smoke alarm you have now. If it connects to [line voltage] wires, you’ll want Nest Protect (Wired 120V). If it doesn’t, you should get Nest Protect (Battery). Those colored wires in your ceiling look like 24 gauge thermostat wires, unsuitable for line voltage. I surmise your old smoke directors ran on 24 ...


3

Since you have a R841C (with an integral transformer) You have your terminals on the relay confused. Connect RH to the HOT terminal from the relay and W1 to to the NEUTRAL terminal from the relay. C on the Nest is left unconnected, and you do not need a separate transformer here. If this was an R841D (standalone relay) You have your terminals on the Nest ...


3

With only two wires between the thermostat and the boiler, you're not going to be able to power the thermostat, and call for heat. You'll need at least three wires for that. The C terminal on the controller is likely the COM terminal, though I can't say for sure. According to the schematic, pin 2 of the PCB connector is C. But I'm not sure where it's ...


2

I ended up finding the problem - the black (Rc) and red (R) wires going to my thermostat were joined together in a junction box between the furnace and the thermostat (why I don't know). I've now separated the black from the red, and installed the new thermostat with black as 'C' and red as 'Rh'. It's working great!. Thanks to @chris and @ThreePhaseEei for ...


2

I fixed it myself. In the manual (page 18) there is the following image. As shown on the photo in the question: From left to right: The red "bridge cable" is meant to close the circuit in order for the next two (bus +/-) to work. But the bus connectors only work with with an eBus system. Which is not compatible with the Nest Heatlink. The two wires that ...


2

Zone system A true zone system allows different areas of the house to be isolated, by closing off certain areas using dampers, or just having completely isolated air handlers. This allows fairly accurate control of the temperature each zone, allowing a specific (and if desired, different) temperature to be maintained in each. Multiple sensors The Ecobee ...


2

The guidance we are/have been providing in the comments. The direct answer, is that you have a current carrying wire directly tied the return. (E.g., Neutral & Live In wired together). While this may not be exactly what happened, its an example. Unfortunately, the diagram the book shows you is possibly misleading and therefore it is likely you were ...


2

The object in the photos is a 230V "immersion-heater timer". Most traditional UK heating systems have a "programmer" instead but I guess you could have an installation that just uses the timer. I'm assuming IE practices are similar to the UK. In that case, wire 1 on the old timer would have provided switched-live to a 230V thermostat and the 230V thermostat ...


2

According to the wiring diagram I found, typical wiring is as follows. 1 END SWITCH (To circulator or another valve) 2 END SWITCH (To circulator or another valve) 3 TH/TR (Thermostat and Transformer) 4 TH (Thermostat) 5 TR (Transformer) You'll have to verify this is how your valve is wired, but it looks just like the diagram to me. If this is how it's ...


2

If you have forced air A/C and radiant heat, you almost certainly have two separate transformers. So you'll have to use a thermostat that can work with separate transformers. If the thermostat you choose requires a C wire, you'll likely want to supply the C from the A/C transformer. It's almost always easier to get the C wire from a forced air system, ...


2

Nest customer service is probably your best bet, but I'm going to give you a guess. In a two wire install the Nest charges itself when the boiler is off, using the difference in voltage between the two sides of the on/off relay inside the Nest itself. A small amount of current is allowed to flow through the charging circuit, and back to the power supply ...


2

The voltage drop I saw was due to the triggering of the low water cut off system. When the LWCO kicked on it dropped power to the thermostat. Thank you for the tip @ThreePhaseEel ! Gotta get some of those leaky radiators fixed. As a side-note, the Ecobee handles the power drop better than the Nest. I tried two different Nest-E units and they both read 5-6 ...


2

The Honeywell device does not provide a C wire out. There is fairly open access to it; perhaps you can pull a rabbit out of a hat. Otherwise add a second transformer (2 wires from this new transformer). Phase it correctly, I discuss how to do that here.


2

The wire currently hooked to Y and C will be going off to your air conditioner condenser unit. Y is cooling. C is common, and yes, you can connect another wire to that terminal. You appear to have a two-stage furnace however, with W1 and W2. That means you have a couple options: 1 - Install another wire To take full advantage of two-stage, you need to ...


2

All, I apologize for wasting your time. I feel like an idiot. It was because I didn’t put the face plate back on the heater and the kill switch was on. My bad! Sorry again.


2

Yes, you can use the blue wire the way you have described. Instead of all of that work to attach an extension to the blue wire, I would just cut back some of the brown sheath. That's assuming that there is enough slack in the cable for that to work.


2

Page 17 of the manual linked in the question has the information you need to wire up remote thermostats, that is, to connect wall thermostats rather than using the control panel on the unit. You will have to run five, six, or seven conductor thermostat cable (depending on the unit) from each unit to its thermostat. You could follow those instructions to ...


2

Bit of Nest history Nest often has a sub base issue. Usually the issue is contained to the cooling side. Rh is power input for the heating side. So that wouldn't be my first guess. Test Remove Rh and G and connect them together with a wire nut or simply twisting together. It doesn't have to be a very good connection, it just has to be a connection. This ...


2

On dual transformer systems, Nest expects the common wire to come from the cool side (Nest Pro Guide, bottom of page 20); look towards your A/C not your boiler. If there is a common terminal on your A/C control board and 18/5 wire bundle - use one of the extra wires to connect the common terminal to your Nest 18/3 wire bundle Use Venstar Add-A-Wire (or ...


2

As you can see mine shows replace by April 2026 although I didn’t buy them until end of Aug 2018 and fitted them a couple of months later. I’d better start saving up for the next ones now! So i didn’t get the full product at a discounted price, simply received a reduced lifetime at a higher prorata cost :( Can’t tell you about the end of life nagging but i ...


2

I'm concerned about @ThreePhaseEel's comment on how the Nest will respond to the switching 24VDC that the diode bridge will provide. Although I'm confident that would be an appropriate location to pull a common wire from, I'm going to construct my own circuit from more standard parts.


2

Yes the PY4G unit is compatible with the Nest 3rd Gen Thermostat. I'm guessing that the quote from the manual about power-stealing is to ensure users use the common wire and don't rely on smart thermostats' power-stealing. My issue was that I had 18/8 coming from the outdoor unit that met with 18/5, but only 4 wires {Y-G-W-R} were connected. The junction ...


2

I had a similar issue. Originally the indoor doorbell chime rang, then it stopped ringing the day after install. I found that the reason was that the white Nest connector wires that I added in the chime we’re getting in the way of the electro mechanical solonoid. They were preventing the movement. Once I moved the wires out of the way it started ringing ...


1

Based on this wiring diagram, this looks like a multistage heat pump thermostat (provide control of a two-stage heating/one-stage cooling heat pump system). From left to right in your picture: W2 = Aux. Ht. Relay G = Fan Relay R = Power X = (Note says terminal labeled C/X on some models, and based on diagram, I think your assumption of common wire is ...


1

In my experience Nest's customer support is excellent, they have technicians which seem to be capable of talking homeowners and pros through some fair technical installs. It appears that this is a common question, and that Nest doesn't support this feature yet, but I would call Nest's support line and see if they have any tips.


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