Combi Boiler

kev2009

Only thing I can find is it says:-

RTC (Real Time Clock) Backup

The electronic timer has a Real Time Clock which has a backup supply to maintain the date and time for when

power is removed from the boiler.

When power has been removed for more than 3 hours and is restored, it will be necessary to enter the date

and time again but the programmed periods will have been retained.

But no mention of a battery so unsure what this means.  Also power wasn't out for 3 hours, only few mins max

Kev

Bendy_House

I don't know what a 'real time clock' is, but it could keep hold of the time for 3 hours by using a capacitor, which stores charge - a bit like a teeny battery.

Anyhoo, the Logic timer is just a 'switch'. When it says 'on', it sends power to the old wall stat position, where the Nest receiver now resides. When the timer says 'off', the receiver doesn't get power, so it cannot work.

The Nest does not in any way 'communicate' with the Logic timer, it just gets a timed power supply from it. To repeat - if the timer is 'off' (or broken, or faulty, or doesn't have the correct time set), then the Nest receiver is simply not getting power, so the whole caboodle is non-functioning.

This is a very bad setup. The Nest receiver should not be turned on and off like that by the dodgy Logic; it should be permanently powered up and allowed to do its job. Really, the Logic should either be set to 'on 24hrs', or else electrically by-passed.

This way the Nest gets on with both jobs, timings and temps. As it should.

You then get to grips with the Nest and find out how to operate it properly - assuming it isn't faulty, which it likely isn't.

Go on a Nest support forum, and tell them of any issues you are having with the NEST, and ignore the Logic which is no longer required, and is just being a pita

Once you have the Nest working as it should - reliably giving you the temps you want and at the times you want them - you will chortle at what you're doing now, and then give yourself a good kicking for not sorting it sooner.

kev2009

Hi,

The Heat Link always has power, I can walk up to it when the heating is not on and press it and it will give me a green LED to indicate it is connected and I see it connected to my WIFI router all day, it doesn't go on and off, it has a permanently power supply.  Same for the Nest-E plugging into the wall socket so maybe it is connected differently? the boiler is in Run mode, so uses the Programmer in the boiler to determine when to turn on heating..

I therefore presume, if I switch it to continuous on, then the boiler would then take its heating on from the Nest-E schedule.  

I'll find a Nest Forum and post the issues but I've read on forums that lots of people are unable to make it come on and off at set times and it tends to do what it wants.  Some people have also ditched Nest and moved to other products but I'm not overly familiar with smart thermostats, I only gave this one a go as it was effectively free so was worth a try to see how good/bad it was.  

Thanks

Kev

Bendy_House

kev2009 said:

Hi,

1) The Heat Link always has power, I can walk up to it when the heating is not on and press it and it will give me a green LED to indicate it is connected and I see it connected to my WIFI router all day, it doesn't go on and off, it has a permanently power supply. 

2) Same for the Nest-E plugging into the wall socket so maybe it is connected differently? the boiler is in Run mode, so uses the Programmer in the boiler to determine when to turn on heating..

I therefore presume, if I switch it to continuous on, then the boiler would then take its heating on from the Nest-E schedule.  

Thanks for the clarification, Kev.

Something doesn't add up for me, then. If the Heat Link - the device on the wall which is in the place of the old room stat - is ALWAYS powered, even when the Logic timer is 'off', then it's wired in a different way than I expected, and also not the 'correct' way as far as I understand it.

I wonder - could the Heat Link have a back-up battery so it appears to be 'power-supplied', but is actually running on batteries when the Logic is 'off'?

Yes, the NestE is powered by it's own 'USB' type supply. Bear in mind, tho', that the NestE is the 'controller' - it does all the temps and timings - and the Heat Link is only a receiver, which does the NestE's bidding.

If the Logic timer is making the boiler do stuff that the Nest doesn't want - if it's working independently of the Nest - then it's 'wrong'.

You may be at the stage where a sparky is needed to confirm what's going on. But I still think it would be a shame to not use the Nest to it's full, and stop allowing the Logic to dictate things!

Bendy_House

Ok, the Heat Link IS battery-powered, so that explains why it's always on, regardless of what the Logic says.

If the Nest is therefore saying '27oC' at any point - when it clearly should not be - then that must be a problem with the Nest itself?

Your Logic timer is still obviously part of the 'loop' - ie the controlling signal from the Nest still goes 'through' it, so that if the Logic is 'off', then that signal doesn't get to the boiler, so the boiler goes off too.

It shouldn't ideally be like that - the Logic 'should' be 'on' all of the time, or even completely by-passed; the Nest should be doing everything.

But, it could be your Nest is faulty.

All I can suggest is that you 'web-chat' with Nest about your symptoms, or else use a forum for ditto. I did both for help with my Hive, and they were very good - the 'chat' person even phoned me up after the link got disconnected - very impressed.

Write down what your specific issues are as clearly as possible so that you can explain them in as few words as possible.

kev2009

Yes, I've looked into the Nest-E bit more and it seems it is powered by Batteries so is always on, the original cable is used to the boiler.

So as said programmer turns heat on/off according to its schedule and effectively nest is just setting the temp for it to be at just like the original manual thermostat.  The only difference is, I can control the temp remotely

I thought it had mains power but appears not, I would need an additional cable for that (like the Nest learning needs a mains power supply).

So in turn, the power outage doesn't affect the Nest-E as it has a inbuilt battery (rechargeable I believe) and the heat link has a battery so only thing that happens is Nest-E brings up a message advising its lost power but continues to function via battery.  I'm assuming the Programmer used to remain on too (never looked as its in a cupboard) but whenever power has gone off and back on in the past, the programmer in boiler has always retains date/time etc but no longer.

Hence why I'm thinking it's programmer some how not accepting temp signal from heat link until it has a date/time set on it.

I've left a msg on a Nest forum too but no response so far, it seems lots of posts have no replies so will see if can find another forum for it as hole idea was to have the flexibility to turn on/off when i want but it does tend to do when it wants, even sometimes turns heating on a little bit before my chosen time or leaves on a bit longer past my chosen off time, it just random.

It does seem the Nest Learning has some more features and more controllable so maybe i should just bit the bullet and buy that and then remove inbuilt programmer and just rely solely on nest learning? I believe it will *try* to adapt schedule etc to what it *think* i want by "learning" but I believe this is only for a couple of weeks? So maybe for first 2 weeks I'd be constantly going in and changing the schedule back to what I want and then maybe it will give up and just go with what I've set?

The Nest-E has very little options on it compared to the nest learning, the nest-E looks to be more set it up via the web page or app which is fine as I'd sooner do it that way anyway than on the little round screen but it may have some additional options that will help.

Only concern of moving to Nest learning is I don't believe that heatlink has battery backup its mains only so IF power went out, would it auto re-connect to Nest and WIFI given it takes a bit for my router to power back up.

Thanks

Kev

kev2009

Thanks, the Nest was in Eco mode and when I discovered it, I turned Nest off so that to see if that would stop the heating coming on after power cuts.  The Nest-E has a sensor on it which tells you the temp in the room so hence I could tell the temp in the room was 27 (the heatlink has a sensor too to tell you the temp in the room), the nest wasn't set to 27, the max temp nest is set to at any point in time is 21 on the schedule and I may occasionally up to by 1 or 2 degrees if it gets really cold by that is very rare, most of the time 21 is fine.  So some how, its default to 27 where it got that figure from - would it be that is the max temp of the boiler? I was expecting the max temp to be 30 or 35 but could be wrong.

I've left a msg on Nest forum, will try find another as it seems most posts are not answered on the forum i found, losts of posts but very very few replies

Kev

Bendy_House

Kev, I wouldn't go for Nest Learning as the NestE should be ideal for your needs. It does timings and temps - that's all most folk want, and it's easy to follow and override when needed.
I think your issue is your logic timer... (Did you mention there was another programmer in a cupboard as well?!).
It seems to me that the logic is working in addition to the nest, in 'parallel', instead of letting the Nest take over from it and just being 'fed' from it (series). So, when you have a power cut and the logic's timer goes 'ape', the LOGIC is the device that turns on the boiler and KEEPS it on, not the poor maligned Nest.
The fact the Nest shows 27oC doesn't mean it's the Nest wot's doing it; the Nest is simply reporting what the room temp actually is. (It must feel really warm in there?!)
So, seriously, I think you need to get the Logic right out of there by completely by-passing it, and let the Nest do its job.
You shouldn't have ANY issues with the Nest giving you, say, 14oC overnight, 20oC in the morn, 18oC during the day - WHATEVER it is you want.
The logic needs shooting. As does any other programmer in any cupboard

kev2009

Hi,
No other programmer, just the programmer that's in the logic boiler is all.  The boiler is in a cupboard so its not viewable unless i open the cupboard hence I never paid any notice to the timer before.

Yes, i can try it without the programmer but i need to get a blanking plate to cover up the gap in the boiler as there is no blanking plate as it was fitting with a programmer that sits in the boiler.

Still nest keeps trying to turn on heating during the night or during the day outside the hours - its soo annoying plus i don't get notification to say heating on etc so its only when i check the next day etc that I see oh actually it was on outside of my hours.

Not to mention, when i view history it shows no orange bars on the days at all BUT if i click on the day, then it shows the orange bars for the times it came on... not sure what that issue is.

Obviously atm I've got boiler in off mode so doesn't mater if power goes out etc as boiler cannot come on regardless until i can find a solution for this issue, I'm torn between getting timer that has been 100% reliable until recently and does exactly what i want or getting blanking plate and then hope can sort nest timings out and stop it coming on outside of schedule which seems impossible as I've tried for quiet a while with no joys.

Kev

Bendy_House

No need to physically remove the Logic - just pop it out, disconnect it, fit a by-pass loop, and refit the unit without it being connected.

From what I've seen in a YouTube vid about fitting these Logic progs, there is a plug-in wire loop that needs removing before the Prog is fitted, so that loop will need reinstating if you are removing the unit.

I don't suppose you'd be lucky enough to find that loop sitting behind the Prog?! Folk charge 'silly' for them on t'Bay - around £15, which is nuts.

I'm not saying that this will sort your issues, because I can't tell what's actually at fault. I am just suggesting what I would do in your situation; first I'd fully 'remove' - electrically isolate - the Logic timer as it serves no useful purpose, and is clearly also faulty.

Once removed - by-passed - then I'd tackle the Nest. It can be programmed/scheduled via the App, can't it? I'd go through that process again from scratch, following a written-down list of required temps and timings. Then tell it to get on with it. If it still goes pear-shaped, then it's either because I've done summat wrong with the programming, or else it is faulty...

In general, tho', the Nest is a good thing to have, so I'd - personally - be looking to keep on with it, even if a part needs replacing/repairing.