Posted by: @transparent

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Posted by: @benson

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turns out an external junction box and conduit entry hadn’t been installed properly. This has wiring connections for the cylinder temp sensor that were completely submerged in water that had been getting into the box

That's awful!

... and should've been flagged as an Alert by the software when the cylinder-temp readings no longer passed a sanity-check.

It's likely that water will have been sucked back up the wires due to capillary action.
It might cause further corrosion in time, depending on the cable composition.

I recommend you write some labels with a date, and place them at relevant points in case the corrosion causes another fault in a year or two.
"Sensor wire, water ingress 07jun25" should do it.

Place one inside that external box, and another on the cylinder next to the temp sensor.

Or alternatively, if there's sufficient spare cable to pull through, snip out 150mm each side of the junction in the box and re-make the connection.

The homely dashboard was useful in diagnosing For sure an error code would have been useful as well but we definitely didn't have that.

Thanks for the tips regarding the wiring. I will have a look and see if there is any slack. I don't think there is though. To be honest the temp sensor and wiring looks like a really cheap bit of kit, so I suspect we'll have to replace it all at some point. The biggest issue I'm guessing will be how we feed a replacement wire through the conduit as it goes through the loft cavity wall at the gable end, then a few metres down the side of our house. It's only 25mm and has a couple of other cables in it as well.

@benson If there IS sufficient room for the cables in the conduit to move about a bit (Thank you Tony Hancock!), you could securely attach a new (replacement cable) to the old cable you wish to replace ensuring a smooth taper at the joint rather than any abrupt edges that might snag. Possibly having someone to ease the new cable into the conduit, gently pull on the old cable at the external end and ease the replacement through the entire length until the replacement can be seen at the external site.

N.B. if the conduit is roomy enough for it, also pull through a drawstring and leave a little spare at both end labeled to indicate why it is there. Regards, Toodles.

Posted by: @benson

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The biggest issue I'm guessing will be how we feed a replacement wire through the conduit as it goes through the loft cavity wall at the gable end, then a few metres down the side of our house. It's only 25mm and has a couple of other cables in it as well.

I have years of experience in pulling wires through conduits, gaps below floorboards and timber-framed walls 😊 

It's usually sufficient to bind the new cable to the old one with PVC electrical-tape, and then pull steadily from the other end.

In your case, you want to feed from the loft, so that gravity works to your advantage.

If I think there's a chance of the cables parting company mid-way, then I also bind the end of some nylon garden-twine onto the old cable.
At least I then end up with the twine in the conduit when I pull out the old cable.

If that all fails, then buy a 30m-long nylon cable draw-tape from Screwfix (or similar outlet)

The dark bendy end goes in first.
That leaves you with a brass eyelet to which you attach the new cable.

I hope all those other cables in the conduit are ELV (below 75v).

Electricians may not use the same conduit for mains wires and signal wires, even if they're double-insulated.

@transparent and @toodles of course. Forgot I could attach it to the old wiring and pull it through, should a complete replacement be required. It is all the low voltage connections for that conduit run. Thanks

I think what this latest issue (in a long list of issues) highlights again the inherent problem with installer access to homely. 

Homely evidently want only the original installer to access the dashboard/installer app, for the lifetime of the system. The last people we want to have sole access to, to our ashp , is the original installer. I emailed them yesterday telling them that I no longer consent to our data being shared with them, but I don't want to toggle the access completely off on our homely account as this means no one can remotely access it, including us. Will see what they say.

Something I've been wondering for a while....

Homely on their website claim a 31% reduction in yearly bills (which is a bold claim to make without any "up to" qualification, but that's another topic), but I've never seen anything to say 31% of what. Is it 31% off a typical "run it like a boiler" installation or is it 31% off the cost of a properly installed system set up with sensible weather compensation and properly balanced radiators etc.? I don't doubt that Homely and its competitors can show some further savings by very active management of an already efficient system but I'd be interested how much improvement one can expect on an install without glaring issues (i.e. one that would bear the scrutiny of this forum, for instance).

The reason I'm wondering, of course, is that there comes a point when the downsides outweight the benefits. Homely's service that includes optimisation for smart tariffs already needs to show a £25 p.a. improvement just to break even and if a customer has to waste time and effort to get to information (e.g. stats) they are being kept from by Homely then a cost has to be added to that too. In contrast, Havenwise have so far demonstrated a commendable degree of customer focus and therefore seem to represent a lower "customer frustration" cost, and I would expect that must affect the light in which Homely's service is viewed. 

@majordennisbloodnok I suppose that (in my own case at least) the choices were:

1. Run with a on/off thermostat as supplied by installers.

2. Fit a Homely control system.

3. Fit a Havenwise or Home Assistant control system.

The first option was not to my liking as very unkind to heat pumps and efficiency. Though I set the system with WC and adjusted the curves, I was never confident that the settings were optimal and I found at either extremes of OAT, I had to tweak the tweaks far too often for comfort! The thermostatic on/off bang bang method was just a temporary means to an end anyway.

Option 3 was never going to be my choice as I am neither good at coding / programming or even following other’s cribs of code for instructions; to this, adding my poor sight meant this really is a no-no. In addition such a system would not be controllable by my better half should I go under a bus or something!

Option 2 means I leave the control to others but that my wife could also do the same with confidence as it would ‘just work’ in my absence. Having discussed my needs at great length with Homely over some 6 months or so, I felt fairly confident to trust them to do their best and that this would suffice for me.

I don’t need the £25 per annum option as with battery supply flattening out the TOU restrictions, I can run without the Smart+ extras and it doesn’t really impinge on the efficiency. As to whether the control is optimised? I can’t be sure but, cold winter conditions usually provide a COP of 3+ and mild weather 4.5 - 5.6. My wife can operate the basic Homely menu if that murderous bus comes along - so I am fairly happy. Regards, Toodles.

@majordennisbloodnok it explains it further here in terms of what they were comparing it to. The headline figure is indeed comparing it to fixed flow temp from what I can see:

homely blog

That said, agree with toodles. Our Clivet seems to perform quite well with it- we'd have to revert back to an on/off thermostat if we didn't have it as there is no available alternative that offers similar, as far as we know. We have come to appreciate homely, despite the frustrations.

Posted by: @toodles

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@majordennisbloodnok I suppose that (in my own case at least) the choices were:

1. Run with a on/off thermostat as supplied by installers.

2. Fit a Homely control system.

3. Fit a Havenwise or Home Assistant control system.

The first option was not to my liking as very unkind to heat pumps and efficiency. Though I set the system with WC and adjusted the curves, I was never confident that the settings were optimal and I found at either extremes of OAT, I had to tweak the tweaks far too often for comfort! The thermostatic on/off bang bang method was just a temporary means to an end anyway.

Option 3 was never going to be my choice as I am neither good at coding / programming or even following other’s cribs of code for instructions; to this, adding my poor sight meant this really is a no-no. In addition such a system would not be controllable by my better half should I go under a bus or something!

Option 2 means I leave the control to others but that my wife could also do the same with confidence as it would ‘just work’ in my absence. Having discussed my needs at great length with Homely over some 6 months or so, I felt fairly confident to trust them to do their best and that this would suffice for me.

I don’t need the £25 per annum option as with battery supply flattening out the TOU restrictions, I can run without the Smart+ extras and it doesn’t really impinge on the efficiency. As to whether the control is optimised? I can’t be sure but, cold winter conditions usually provide a COP of 3+ and mild weather 4.5 - 5.6. My wife can operate the basic Homely menu if that murderous bus comes along - so I am fairly happy. Regards, Toodles.

I can certainly understand why you made your choice, @toodles, and I'm well aware you've been happy with the choice since then. There are a couple of points I'd make, though, about your last post.

Firstly, I'd suggest people will normally have four options rather than the three you outlined. Instead of having an installer provide a thermostat and choosing to run with that, most people we see on the forum now are recognising they can insist on a system installed with weather compensation and choose to run just like that without any thermostats at all. That fourth option is the preferred for quite a lot of forum members and the posted stats/bills for many of these installs show very good running costs already. Given that's realistic now, my query was how much Homely can then improve on that already good figure. If the answer is "not that much" and Homely choose to be awkward about providing access to running stats, I wonder how many potential customers will just walk away having decided it's not worth it to squeeze the last few quid out of the system. Of course, if Homely's improvement is still a substantial chunk of money, I suspect those potential customers would put up with quite a lot, but if Homely are "hiding" the performance figures how can one tell?

Secondly, you've lumped Havenwise with Home Assistant and I'm not sure that's all that accurate. From what I can tell, Havenwise is - from the customer's viewpoint - Homely without the little white box, so someone would find both systems fairly similar to use. Home Assistant is a whole different beast and, whilst able to do the Homely/Havenwise job (if configured appropriately), it's far more all-encompassing and far more hands-on as you suggested. In short, I'd personally put Homely and Havenwise together in your point 2.

If the Homely box blew up tonight (or experienced some other form of catastrophic failure), would your heating system continue to work on weather compensation or fixed flow? If the former, have you ever contemplated turning it off for a month or two and seeing what your bills look like without it, just as a comparison? Not suggesting that's what you should do yourself, but it's the result of exactly that test I'd love to know.

Posted by: @benson

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@majordennisbloodnok it explains it further here in terms of what they were comparing it to. The headline figure is indeed comparing it to fixed flow temp from what I can see:

homely blog

That said, agree with toodles. Our Clivet seems to perform quite well with it- we'd have to revert back to an on/off thermostat if we didn't have it as there is no available alternative that offers similar, as far as we know. We have come to appreciate homely, despite the frustrations.

Thanks, @benson; that's helpful. 

To be clear, I'm not against Homely per se but I do worry about obfuscating spin wherever I see it. Given most of the claimed savings are actually possible to realise simply by setting up a heat pump to run low and slow with weather compensation, the actual value I see from the likes of Homely, Havenwise or even getting clever with Home Assistant is the extra savings from active management. The table you linked to suggests the real benefit of such systems is more in the line of £100-150 per year - still not to be sniffed at.

The real savings become more difficult to measure accurately, though, when one adds in a battery and I suspect Homely and Havenwise' blind spot here may mean the financial benefit is much less. I, for instance, only have a 6kWh battery but that's almost always enough to take us through the 4-7pm expensive stretch (we're on Octopus Agile). Because of that, I always ensure the battery is pretty much full by 4pm whether from solar PV or, if necessary, charging from grid at cheap points. In effect, rather than micromanaging the heat pump to vary its consumption according to prevailing prices and conditions, I'm micromanaging my electricity supply to let the heat pump do its low/slow thing uninterrupted. Two different ways of achieving the same thing.

Both Homely and Havenwise have at one point or another expressed a view that, longer term, their development strategy will include management of a wider range of devices - batteries and solar PV in particular. Once that's in place, their products will effectively be similar to Home Assistant with a greater degree of plug and play (i.e. more approachable for non techies). I also think, at that point, that the real world savings they can make for a household will increase significantly so I look forward to that point.

In the meantime, any customer's efforts to estimate a Homely/Havenwise/Home Assistant (or other home automation system) installation's benefit are only as good as the data they can get to work on. With Home Assistant, that's easy; it's your installation so it's your data so you're only limited by your ability to use the software. With Havenwise, it appears they encourage educated customers so the data's available if wanted. With Homely, they're actively standing in the way and trying to "mark their own homework". To me, that's obfuscating spin and that worries me.

@majordennisbloodnok Regarding option 1, I omited to mention that after just a few days after commissioning, I set the on/off unkinthermostat to several degrees above maximum required and allowed the WC and adjustment of the curves/slopes to do the controlling anyway; it is just that I found the extremes of the range required manual tweaking frequently. This was probably due to my inadequacies in setting the slopes correctly but the commissioning had been carried out in a very mild spell in February 2023 and even getting the pump to run was problematical! The installer found that the internal setting for OAT cutoff was set too low when I delved into the problem.

Now, sorry if I lumped Havenwise and HA together, this is through total ignorance of both products I’m afraid. I didn’t try comparing Havenwise as I already had Homely up and running when I first heard mention of Havenwise.

As to your questions on Homely failing, I would just revert to the Daikin MMI and WC control until sorted out. As to comparing running with and without Homely control; I’ll let someone else try that exercise thanks! Regards, Toodles.

Posted by: @toodles

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@majordennisbloodnok Regarding option 1, I omited to mention that after just a few days after commissioning, I set the on/off unkinthermostat to several degrees above maximum required and allowed the WC and adjustment of the curves/slopes to do the controlling anyway; it is just that I found the extremes of the range required manual tweaking frequently. This was probably due to my inadequacies in setting the slopes correctly but the commissioning had been carried out in a very mild spell in February 2023 and even getting the pump to run was problematical! The installer found that the internal setting for OAT cutoff was set too low when I delved into the problem.

And being entirely frank about it, that is part of the appeal of the likes of Homely and Havenwise; they offer a plug and play way for customers to keep those awkward adjustments at arm's length. There is certainly value in that and it shouldn't be underestimated.

Posted by: @toodles

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Now, sorry if I lumped Havenwise and HA together, this is through total ignorance of both products I’m afraid. I didn’t try comparing Havenwise as I already had Homely up and running when I first heard mention of Havenwise.

No apology needed. I only mentioned since if someone discounted Havenwise thinking it was complex like Home Assistant then that would mean Homely was in a monopoly. In fact, Homely and Havenwise are in many ways interchangeable products since what they provide is an almost identical service - just via different methods - and so new potential customers now have some choice.

Posted by: @toodles

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As to your questions on Homely failing, I would just revert to the Daikin MMI and WC control until sorted out. As to comparing running with and without Homely control; I’ll let someone else try that exercise thanks! Regards, Toodles.

Yes, I thought you'd opt out of that particular bit of disruption. Don't blame you. I might want the answer but I certainly don't want anyone to risk anything to get it for me. 😀