Worcester junior 24i and Nest thermostat

yes that will work,before you power it back up double check that the fused spur has a 3 Amp fuse fitted
 
Sponsored Links
Yeah just checked and it's 3amp. One thing I'm curious about. The boiler has the spur switch and also a switch adjacent to it with a red light, which as far as I can tell doesn't affect the boiler at all. I'm curious as to what it is, as switching that on and off does nothing at all that I can figure out.
 
If you had a HW cylinder before the combi was fitted it is possibly the isolator for the old immersion heater
 
Ok, so wiring it up only took a few minutes, but it isn't triggering the heating. I can turn the dial on the thermostat and hear the relay clicking in the heatlink, but it isn't switching the heating on.

Edit: did also set the manual timer to always be on with the central switch

double edit: schoolboy error....clamped onto the insulation instead of one of the wires
 
Last edited:
Sponsored Links
Moving now so no longer matters, however I tried to control a Bosch Worcester only to go around in circles, it seems early boilers can be switched on or off, but there was no ability to connect to the bus, latter did have connection but not opentherm voltage, so your limited to Wave, which may work in an open plan house but not where you want to control each room independently.

It seems only way to control the boiler is with the return water temperature, although you can turn it off/on electrically. As it if it is worth fitting a thermostat to turn it off, is a big question.

Heart of winter likely not worth it, as modulating the boiler is a more efficient method than turning it off/on. However as summer gets closer there may be days when the heating could be turned off, it could likely be turned off just as easy with a relay as a thermostat, if we could write a program "If any TRV head target is above actual then run boiler" it would work. And there are IFTTT programs being released every day, so maybe it now can be done.

However only automated way I could see was to have a series of off/on thermostats in parallel so if any calls for heat the boiler will run, which seems a little daft as you already have a good thermostat in the TRV head that will report to a computer actual and target but I could not find out how to actually use the info to turn boiler off/on.

I have a wall thermostat, however it is used like a switch, if cold turn it up, if warm turn it down, so it could be just as easy an off/on switch.
 
Moving now so no longer matters, however I tried to control a Bosch Worcester only to go around in circles, it seems early boilers can be switched on or off, but there was no ability to connect to the bus, latter did have connection but not opentherm voltage, so your limited to Wave, which may work in an open plan house but not where you want to control each room independently.

It seems only way to control the boiler is with the return water temperature, although you can turn it off/on electrically. As it if it is worth fitting a thermostat to turn it off, is a big question.

Heart of winter likely not worth it, as modulating the boiler is a more efficient method than turning it off/on. However as summer gets closer there may be days when the heating could be turned off, it could likely be turned off just as easy with a relay as a thermostat, if we could write a program "If any TRV head target is above actual then run boiler" it would work. And there are IFTTT programs being released every day, so maybe it now can be done.

However only automated way I could see was to have a series of off/on thermostats in parallel so if any calls for heat the boiler will run, which seems a little daft as you already have a good thermostat in the TRV head that will report to a computer actual and target but I could not find out how to actually use the info to turn boiler off/on.

I have a wall thermostat, however it is used like a switch, if cold turn it up, if warm turn it down, so it could be just as easy an off/on switch.
have you answered the wrong post ?????
 
So now this is installed have I come across an obvious drawback? The combi boiler I have, has a heat dial on the front of it that controls (not very accurately) the heat to the radiators as well as the regular hot water.

At the moment, even if I say, tell the Nest to set the room to 21 degrees, the boiler is switching itself on and off, apparently based off wherever the heat dial is set on the front of it?

I could get around it, I guess, by turning it all the way to maximum, but then I get scolding hot water out of the hot tap. How are people settings theirs up? Thanks
 
The nest hasnt a clue what your boiler thermostat is set anymore than the boiler knows what the nest is set to, the boiler thermostat is the maximum temp that the boiler can reach before cutting out, the nest senses the air temperature in the room that it is situated and when the air temp reaches the set point it will tell the boiler to shut down, HW temp should not be affected by either
 
Oh yeah I get all that. It's just that my boiler is turning itself on and off, seemingly having it's own idea of what temperature it should be, completely ignoring the Nest settings telling it when it should be on and off.

I'm also finding the Nest seems really slow in reacting to changes in temperature. The actual reading takes an age to update. No idea why, maybe placement has something to do with it. I'll see if it learns anything in the next week or so. But not overly impressed so far.
 
does your boiler have an inbuilt timer still installed ? if so which one ?
 
It's just a bog standard mechanical timer which I have switched to the permanent on setting as per your earlier recommendation.

I do appreciate your replies and help by the way :)
 
I could get around it, I guess, by turning it all the way to maximum, but then I get scolding hot water out of the hot tap. How are people settings theirs up? Thanks
The DHW is pre set and can not be adjusted, doesnt matter what temp you set the control for the heating it will not affect the HW temperature.

https://www.wolverhamptonhomes.org....ior_User_Instructions_Customer_Care_Guide.pdf

Page 8

Try the heating set quite HI and see what happens with the nest, if it is still random when the boiler switches off, go to the heatlink and see if it is shownig a demand and see if the nest is showing as demanding
 
Mines not like that model. This is mine:
https://i2.wp.com/justcentralheating.co.uk/wp-content/uploads/2013/01/IMG_2094.jpg

And on mine it does actually affect the hot water. It explains it in the manual. Basically as you turn up the heat dial, it slows down the running water going though to the hot tap, therefore heating it up more.

I think I have found a decent balance now though. I've gone around 3/4 of the way up on the main dial, and that seems to have the boiler turning on and off when the Nest tells it. Rather than it doing it itself. I assume because 3/4 is higher than the temp I have set the Nest to.

Still not convinced by the Nests temp readings in the room I have it in though. It is a reasonably well insulated room, but once it reaches a temp I'm happy with, the Nest will show it sticking at that temp for hours afterwards, even when I switch a cooling fan on to bring the temperature down and see if the Nest display reacts.

It is responding better to increases temperature though, since I did a reset on it.

edit: I'm also curious about the temp dial on the front there. At the 3 o'clock position it shows a dot. What does that indicate, because you can turn past that. In every manual I can find online, it doesn't mention that dot, and in fact doesn't even show it at all.
 
Last edited:
And on mine it does actually affect the hot water. It explains it in the manual. Basically as you turn up the heat dial, it slows down the running water going though to the hot tap, therefore heating it up more.
You have read that wrong, the temp dial can not alter the flow rate in any way
 
Hi All,

I'm off to look at installing a Nest to the Greenstar Junior 24i later, I've already fitted mine to a Biasi which works perfectly. The Greenstar has an existing thermostat/timer in the hall so just wanted to know if this needs disconnecting or does it work in conjunction with the Nest?

Thanks

Mick
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Back
Top