Combi Boiler

kev2009

Thanks, yes I saw that on the site but I'm dubious as its about half the price and it also seems there is another website with same location whereby the break boilers down so I'm not sure if it would be "brand new" or removed from a boiler i.e. maybe one in a show room used for demos etc and therefore would it be brand new and last or would i only get couple of years before it plays up too,  Considering everywhere else is twice the price, I'm a bit cautious of that one.

I found the timer loop & blank plate for my boiler, together with delivery is approx. £30 so not too bad.  I just fell short when i was looking at where I plug the loop into as the timer has 2 connectors left and right but no real info on what the connectors do and which one (or maybe both) need looping.

I've not tried it on continuous but in Run mode when power goes out & comes back on - Nest does nothing at all - i can change temp, turn heat off etc but boiler doesn't seem to get the signals it ignores it and I think its because until the date/time etc is entered, it hasn't been "initialised" so to speak so it ignores all inputs until then.

I was hoping I'd have more time to look at this but looks like it starting to get bit colder again so might need to come up with a quick fix or as you suggest switch to continuous and cross my fingers power doesn't go out

Unfortunately at present between work and being with parents due to Dad unwell at the moment, I'm not home much to play around with the settings etc.

Kev

Bendy_House

I'm not surprised that the Nest doesn't work after a power outage if the Logic isn't at the correct time and it's in 'RUN' mode; 'RUN' will require the clock time and the set 'on' times to correspond before the Logic relay goes 'click' and allows power through to the Nest. If the clock is wrong, or not even working, then the whole caboodle is unlikely to work.

If you set the Logic to 'CONST ON', I am going to guess it doesn't rely on a switching relay like 'RUN' does, but just the actual physical rotary control on the front making a direct switching-through connection; ergo, if your control is on CONST ON, power should go to the Nest constantly, and regardless of whether the clock is correct or even working.

If you had a pro installer come in to fit your Nest or Hive or Wiser or whatevs today, that is what they'd do - set the boiler's timer to 'CONST ON', and threaten to break your fingers if you touched it. OR, they might disconnect your Logic and fit a by-pass link.

These are the correct ways to do this, and I will repeat - running your Nest via a timed on/off supply might seem like a good idea since you are having some weird stuff with your Nest, but it ain't right. And you won't sort out your Nest issues whilst you are doing this. It's almost like wondering why there's no water coming out your garden hose nozzle, whilst knowing that there's someone at the tap who might be randomly turning it on and off. There could be two possible reasons why there's no water!

Here you go - both items for just over a £enner: https://www.ebay.co.uk/itm/125004228462?hash=item1d1ad5276e:g:vfQAAOSwmlhhkooa

or, a brand new link by itself for a  £enner: https://www.ebay.co.uk/itm/312944222951?epid=21019469583&hash=item48dcede2e7:g:1CwAAOSwe-hesSbZ and just reposition the existing - disconnected - clock.

All I'd suggest is that you first look at the top-LH socket behind the Logic and check it has 5 terminals like these links do - I'm pretty sure it will (tho' the link only spans 2 terminals).

It's your call, but I think you'd be nuts to buy a whole new Logic timer. There is an obvious thing to do here, and it's the 'correct' way.

kev2009

Thanks, I did email Ideal regarding instructions etc and they have advised I put the timer loop in top left.  There is also a connector top right and I did ask if need anything for that but they haven't answered that questions so I'm assuming I don't need anything but this make me curious as to what does it actually do lol

I'm currently thinking of trying to change the boiler to CONST ON and leave timer in situ as is and in theory it should bypass the timer and let Nest control it.  If this works, then the timer can remain connected but just wont do anything.  IF it doesn't then I'll need to get the timer loop and if I'm doing that, i might as well get blanking plate to fit and remove the ideal programmer altogether since I'd have cover off anyway.  The first option doesn't involve removing the boiler cover i can just set to CONST ON and then try it and see.

I have a switch near the boiler to turn it off so I can effectively mimic a power cut by turning it off and turning it back on after a couple of minutes so that the timer flashes requiring dates etc and then see if Nest can still turn heat on/off as needed.

This way its a £0 fix   In theory const on should by-pass the ideal programmer so it *should* work but some how i suspect I'd need to get the timer loop etc but its worth a shot.

just got to work out if i can go up this weekend.

Kev

Bendy_House

Cool - that's a plan.

The top-RH plug for the timer is its power supply, so as you suggest it ain't needed when/if you want to remove the Logic - just unplug that end, and remove - leave it empty. Only the LH-top socket needs the by-pass (that's the way the bare boiler without controls is supplied - there must be hundreds of these links out there!)

kev2009

Hi all,

Update on this.
So tried the boiler in Const ON with date/time etc set on the programmer in the boiler.
Nest can then control heat on/off, can turn heat off all together and also turn back on and adjust temps etc so all ok there.
However, this is where it all fell apart, when I turn the boiler off(to simulate a power cut) and turn it back on, the programmer in boiler immediate flashed waiting for date/time and it then turns the boiler on.  Anything I do on Nest is ignored i.e. turn heat off, change temp, anything, its all completely ignored.  Setting the date/time on the programmer and Nest can then take control again so I've again left the boiler off for now as any power cut will mean it is running constantly and I can't have that.

Having now confirmed it looks to be the programmer as once its date/time is set, I'm going to look into see what options are, thinking I might just get the loop connector and plug that in and leave the inbuilt programmer in situ but not connected (if there is room) also going to see IF there is a battery backup programmer as my concern is IF I remove inbuilt programmer, plug in the loop connector, if power goes off and comes back on, will boiler run until the next schedule on/off time on Nest or will it talk to Nest and realise oh temps is set to X and then decide turn on or off accordingly or will it just wait for the next signal from nest to indicate turn on/off.

For example, heating goes off at say 10:30pm and temp is set to 10C.  If power cut at 2am for a minute then comes back, will boiler then come on only if temp is below 10C or stay off if above or will it just come on regardless and run until the next schedule Nest command at 6:30am to say heat to 21C?  I'm not sure as I think Nest only sends commands according to schedule so if power cut in-between, what does it do?  Will nest detect power cut and then re-send the last command effectively to the boiler again? not too sure.

Thanks

Kev

kev2009

Hi all,

So small update, I've decided to order the timer loop connector for now, see if it works.

Ordered it last week not heard anything re delivery so unsure when it will come.

Thanks

Kev

Bendy_House

That's interesting, Kev.
So it looks as tho' the 'const on' control on the programmer is STILL dependent on the programmer's time clock being set correctly. Weird. It seems as tho' it defaults to turning on the boiler if the time hasn't been set - it must be by-passing the Nest, which is strange.
Anyhoo, fitting the loop and disconnecting the prog should determine this for certain. Yes, almost certainly there will be room for the prog to be repositioned, and you might not bother replacing this with a blanking plate - there's no need.
Remind me - the Nest's receiver is battery-powered? In which case it should be fully unaffected by power cuts. So, when there's a mains power cut, the Nest doesn't actually know about this, but just keeps on trucking. The receiver is essentially a switch, and when the Nest controller says "turn on the heat..", the receiver goes 'click' in response, to do so. It doesn't 'know' if this has been successful - it just does it. If the mains power is off, if the boiler has exploded, it doesn't matter - the receiver will still go 'click - turn on'. 
So, once power has been restored, the Nest will be doing what it always does, so it'll be saying 10oC, or 20oC or whatevs, and the boiler SHOULD just respond in accordance to what the Nest is telling it at that moment.
Anyhoo, once the link arrives, you should be able to confirm.
Fingers crossed

kev2009

Hi,

Thanks, yes indeed, without a date/time on the programmer, it ignores anything else until set.

So this is where I was a little unsure... for example..

Lets say Nest is set to below schedule..

11am set temp to 21C
2pm set temp to 10C
4pm set temp to 21C

Assuming no power cuts....
At 11am, Nest set temp to 21C, heat link goes click and boiler comes on if below 21C... 
At 2pm Nest set temp to 10C, heat link goes click and boiler goes off.
At 4pm Nest set temp to 21C, heat link goes click and boiler comes on if below 21C... 

All ok, so far...

Now IF I had a power cut at 11:30am, what would happen if:-
At 11am, Nest set temp to 21C, heat link goes click and boiler comes on if below 21C... 
At 11:30am power cut... Nest and Heat-link have batteries so they remain on and in communication but boiler is off.  When boiler comes back on at say 11:40am, I presume Nest won't resend the "set temp to 21C" and heat link wont go click as I presume it did this at 11am and now wont do anything until 2pm... So will heat come on until 2pm (assuming under 21C) or will it remain off?  At 2pm Nest sets temp to 10C, heat link goes click and then boiler comes on if below 10C or remains/goes off.

At 4pm Nest set temp to 21C, heat link goes click and boiler comes on if below 21C... 

similarly, if the power went out at say 2:30pm and came back at 2:40pm, would it remain off or come on and wait till Nest sends next signal at 4pm etc?

OR in best case scenario, does Nest detect power has gone off and when it is restored, wait a few mins for boiler to "initialise" so to speak and then re-send the previous command i.e at 11:40, it re-sends the 11am command of set temp to 21C and for the later example at 2:40, would it re-send the 2pm command to set to 10C?

Thanks

Kevin

kev2009

Thanks, yes I ordered it on Thurs but delivery info was a bit unclear it was down as standard but no real info on when it will arrive, got it from hsp as I liked the site as it showed pics of the boiler components so quiet handy to try and see what's what and i could see the timer in one of them which confirmed top left so decided as site was useful to order from them, said I would get a email confirming delivery shortly after but nothing so far so might have to try chase tomorrow as no word of it being despatched or anything so far, just a order confirmation and payment taken.

Kev

Bendy_House

kev2009 said:

Hi,

Thanks, yes indeed, without a date/time on the programmer, it ignores anything else until set.

So this is where I was a little unsure... for example..

Lets say Nest is set to below schedule..

11am set temp to 21C
2pm set temp to 10C
4pm set temp to 21C

Assuming no power cuts....
At 11am, Nest set temp to 21C, heat link goes click and boiler comes on if below 21C... 
At 2pm Nest set temp to 10C, heat link goes click and boiler goes off.
At 4pm Nest set temp to 21C, heat link goes click and boiler comes on if below 21C... 

All ok, so far...

Now IF I had a power cut at 11:30am, what would happen if:-
At 11am, Nest set temp to 21C, heat link goes click and boiler comes on if below 21C... 
At 11:30am power cut... Nest and Heat-link have batteries so they remain on and in communication but boiler is off.  When boiler comes back on at say 11:40am, I presume Nest won't resend the "set temp to 21C" and heat link wont go click as I presume it did this at 11am and now wont do anything until 2pm... So will heat come on until 2pm (assuming under 21C) or will it remain off?  At 2pm Nest sets temp to 10C, heat link goes click and then boiler comes on if below 10C or remains/goes off.

At 4pm Nest set temp to 21C, heat link goes click and boiler comes on if below 21C... 

similarly, if the power went out at say 2:30pm and came back at 2:40pm, would it remain off or come on and wait till Nest sends next signal at 4pm etc?

OR in best case scenario, does Nest detect power has gone off and when it is restored, wait a few mins for boiler to "initialise" so to speak and then re-send the previous command i.e at 11:40, it re-sends the 11am command of set temp to 21C and for the later example at 2:40, would it re-send the 2pm command to set to 10C?

Thanks

Kevin

AfaIk, the Nest will operate in a similar way to the Hive. Ie, there is a battery-powered Programmable Thermostat with which you set the required temps and times and which detects the room temp. And then there's a receiver. The receiver with the Nest is battery-powered, and the Hive's is mains-powered. But that doesn't matter; ALL that the receiver does is to 'listen' to the ProgStat and act on what it's being told.

And it's as simple as this: IF the ProgStat tells the receiver to turn the boiler 'on', the receiver will close a relay switch and this will send an 'on' signal to the boiler. WHEN the ProgStat says either "I've reached temp - turn the boiler off", OR the ProgStat reaches the next set program such as the 10oC setting at 2pm, then the receiver will respond by opening the relay and breaking the 'on' signal to the boiler.

The receiver isn't trying to work anything out, it just goes 'on' and 'off' when the Prog Stat tells it to. It doesn't 'know' if there's a power cut, it just sits there dumbly waiting to be told what to do - on or off. If a power cut DOES occur, then the receiver is oblivious to it.

Similarly, the ProgStat doesn't know if there's been a power cut. It, too, just sits there constantly detecting the room temp, and obeying the program - what temp have you set for what time. If a power cut occurs, it is oblivious to this - it is still measuring the room temp, still obeying the Prog settings, still sending its signal to the receiver.

So, to answer your 'power-cut' scenario, at 11am the Prog Stat obeys "Turn on until the room is at 21oC, or until 2pm is arrived at". It tells the receiver to turn the boiler on, and the receiver obeys, and goes 'click' and does so. The boiler comes on. Then, at 11.30am there is a power cut - the boiler goes off because it has no power. The receiver is still saying 'on', because it has batteries; it does not know there's a power cut. The ProgStat is still measuring the temp, and will be sensing that the temp might be dropping, but that doesn't ring any alarm bells - it just dumbly keeps saying 'on' to the receiver.

Then, at 11.40am, the power comes back on. ALL that happens now is that the boiler has power, realises it has an 'on' signal from the receiver, and therefore goes back on. It'll stay on - as before - until the P-S/receiver says either "I've reached 21oC - go offski", or the PS/receiver says "It's 2pm, so turn off until I tell you it's reached 10oC".

Or, in one line, it should not matter at all that there's been a powercut - both the ProgStat AND the receiver keep on doing their job regardless, and the boiler should simply pick up from where it left off.