@old_scientist I took a closer look behind the pump this morning.  As I'd expected, there are two anti-freeze valves (as least I think that's what they are) which are deliberately exposed, along with the red and blue isolator valve 'things' (official technical term!) further along.

It might not look the neatest in the photo, but it's not a section of pipework that can be completely enclosed due to various "sticky outy bits" (another official technical term!) and I'm quite relaxed that any heat inefficiencies in the work are likely to be minimal.

Personally, the biggest eyesore in the photo is the gravel bag, which has been left temporarily for someone to return to and use to top up the heatsink when they're next in the area.  I could have removed it for the photos but have left as is, for which I believe the official technical term is 'lazy' on my part.

Posted by: @sheriff-fatman

↑

@old_scientist I took a closer look behind the pump this morning.  As I'd expected, there are two anti-freeze valves (as least I think that's what they are) which are deliberately exposed, along with the red and blue isolator valve 'things' (official technical term!) further along.

Anitfreeze valves, or at least the ends of antifreeze valves, should be exposed, the idea is that if the heating isnt on when the OAT approaches freezing, they get cold and open

Personally I think there is logic in leaving the shutoff valves exposed also, if you need to shut them off in a hurry you don't want to be fiddling around removing insulation, nor do you want the handles to be hot.  Others, Im sure, will disagree.

That outside pipework would concern me. Surely rigid sections accommodating the valves, and then properly supported with brackets? The rest inside looks ok but I would not be happy with that and personally I'd be getting them back.

Speaking from some experience of dealing with some highly suspect plumbing that we have inherited in our current house, the pipework that seems to be most prone to leaking is unsupported pipework carrying hot water. 

Great that they got it done in two days but that part at least has been rushed. 

A few initial thoughts on Havenwise, from a new end-user perspective:

Signing up to Havenwise was something I'd always had in mind once the system was installed.  Compared to the hard-installed 3rd party controllers, such as Homely, this looked to me to be a much more cost effective solution to optimise heat pump usage, as a software only solution which connects to your system, sees how it runs and, assuming the end user gives permission, then takes over the control of the heat pump based on settings that you request via the Havenwise app.

At present, there's very little end user testimony out there (at least as far as I could see) so I thought I'd provide a bit of initial feedback on it, as a new user.

The first thing to say is that I've been in correspondence over the past few days with both Henri, @hcas on here, and Alex from Havenwise, and both have been responsive to emails with minimal delay, so the user support aspect is excellent, in terms of dealing with any queries that arise.  Baring in mind that I'm currently within an initial free trial of the product, the response level has been excellent.

I've already documented the setup process, which is very straightforward, in an earlier email.  This post is more of a user experience from the point at which someone hits the button to allow system control.  Some of the functionality works exactly as expected, but there are also some quirks that might also cause a bit of confusion, depending on the level of understanding of the end user.  Logically, I would assume that anyone currently signed up to Havenwise are primarily users at the higher level of comprehension regarding heat pump operation, but presumably this won't always be the case as uptake increases, both of heat pumps and the Havenwise system.

The heating function works largely as you'd expect, and is very similar to how you'd operate the heating within MelCloud, or equivalent system for other manufacturers, in that you create a schedule of target temperatures for the house and the system will use a form of weather compensation to achieve this as efficiently as possible.  The only slight quirk to the setup is that the day starts from midnight, so I've had to split the timer into two parts at the start and end of the day for the lower overnight setting (as per screenshot below).  This is exactly how the timer settings on my Sunsynk PV system works too, so wasn't an issue.

The immediate change you notice from Havenwise taking over, is that it moves the default set points for both heating and DHW to the extreme ends of the system range, essentially to prevent them interfering with Havenwise' own settings.  The screenshot below shows the exact moment that this occurred as it shows the two set points changing.  The heating target within MelCloud moves up to 29.5°C and the minimum temperature for DHW drops to 10°C.  The first one is the more significant of the two, from a home user standpoint, as this then also shows up on the in-house thermostat display, and may potentially cause confusion to other household users, such as my wife.  I had concerns that she might see this showing on the display and try to correct it, thinking that the system was attempting to reach the target temperature, so I made a point of showing her the display and telling her that it wasn't a problem.

Beyond the setup, it's hard to feed back much more on the heating operation so far, as it's not having to do anything in terms of needing to heat the house.  We're currently exceeding the target temperatures at all times, so the heating system simply sits idle for now.  I'll update further, as and when we start to see the heating operation in action, but so far, so good.

The DHW setup is a bit more involved, and is somewhat different from the setup that you'd operate directly within MelCloud, although it initially appears to be very similar.  Within Havenwise, you set up a target temperature and a time that you want water to be available at this temperature, and the system will then provide the most efficient method to deliver this to you, using the information you have provided regarding your electricity tariff.  In my case, on the Octopus Intelligent Go tariff, it heats the water when the 7p/kWh overnight rate kicks in, to minimise the cost of heating it.

The difference in operation relates to what happens in between these settings.  Within MelCloud there is a hysteresis setting which subsequently tops up the heating of the water once it falls below a certain delta from the set temperature.  Within Havenwise, the system set temperature is 10°C, so this process is essentially over-ridden, and the water will cool naturally in the tank until the next set point is reached.  The efficiency of the cylinder should logically minimise the impact of cooling but our usage on Saturday threw up an issue which required some back and forth with the Havenwise guys to fully comprehend.

The issue arose when my wife took a shower at around 9:25am on Saturday morning.  Ordinarily, on a weekday, she showers just after 6am, so the set point we had created for all days in Havenwise was to have water at a target temperature by 6am.  She had mentioned that the shower had been hot on the first morning she showered, so I had set a target temperature of 45°C for that morning, to see what the reaction to that was.  After her shower, she said that the water felt very cool, to the extent that she had to shower using the maximum temperature setting to get it to feel warm, which was a signal that I needed to increase the setting.  However, when I looked at the MelCloud data, I was alarmed to see that the hot water temperature had dropped from 45°C to just over 20°C in the space of a shower lasting less than 10 minutes.

The initial feedback from Henri was that this might be related to the location of the temperature sensor in the cylinder, which is sometimes quite low down so that temperature changes are detected early, and the logic being that there is still a reasonable volume of hotter water sitting above this.  My sensor looks to be about 1/3 of the way up the cylinder, so this seemed logical at the time.

A couple of hours later, and with the DHW temp now showing 19.5°C, I touch checked the cylinder on the point where the installer said you could feel if water was hot, and it was cold.  Cue ensuing worry that there was a fault with the system.  At that point I hit the boost button on the hot water and was relieved to see it kick in as expected.  The pump was working hard and it restored the temperature fairly quickly (possibly with the assistance of the immersion heater).

A bit of investigation later, and it turns out that both girls had subsequently had showers that morning, with the eldest daughter mentioning that the water had gone cold for hers (the 3rd one, and from someone notorious for spending far too long in the shower).  These don't show up on the heat history within MelCloud, as the temperature was already recording cold water from the refill from the first one triggering the sensor.  The subsequent showers exhausted the remaining warm supply in the cylinder, hence the water running cold.

It's in this scenario where the Havenwise setup works differently to the natural settings of the heat pump.  When the water runs cold like this, there's no subsequent re-heat of it until the next set time for a target temperature, whereas the hysteresis settings within MelCloud, if used, would have re-heated in real time when triggered by a temperature drop matching the set delta.

In conjunction with further discussion with the team, I've now set several timed set points through the day to try to overcome these issues.  In reality, most of these reheat points will use solar power or stored battery charge (from the overnight cheap rate) to reheat the DHW, and this is something that Havenwise can't detect.  It only knows the rates and times charged on the tariff, so it thinks that these charges will use the daytime tariff for electricity.

I think my expectation was that there would be a bit more flexibility in the Havenwise settings to apply a minimum DHW temperature, but the algorithms are set up to optimise the charging cost, based on the set points so, for someone like me, it's currently a case of setting up an artificial hysteresis function via a schedule something like the above.  It seems that this will likely change in future updates, but the timing of such isn't known as yet.

Overall, based on a few days usage, I'm comfortable that Havenwise will do a good job in optimising the electricity usage for the heat pump, relative to relying on the system settings to do so, and the ability to discuss the situation with Henri and Alex and get quick responses back from them is impressive.  None of the quirks/workarounds described above were particularly difficult to deal with, but they're perhaps not intuitive as part of an initial setup process.  I'll continue to review and fine-tune the settings, and I'm pretty certain that I'll be taking the paid subscription for a year when the initial trial runs out.

I'm fairness to Havenwise the logic of dhw heating is tricky. 

Many people including me have their dhw deliberately set to reheat once per day only.  In this case the hysteresis acts only to stop reheating if the cylinder hasn't cooled sufficiently to justify it.  It seems you prefer DHW priority mode where the dhw reheats as soon as it has dropped below a certain temperature.  That's fine but for many this is needlessly inefficient. 

Which is better depends on usage relative to tank volume, the position of the sensor in the tank, and the times and patterns of use.

Havenwise know none of these although with some logic I think it may be possible to deduce the first two from the energy demand to reheat.  I can't see how they can ever deal with two girls unexpectedly taking long showers at random times, other than revert to DHW priority which of course frustrates any attempt to optimise cost!  It will be interesting to see where they go with this.

@sheriff-fatman Just to add to what James was saying, I think you can also opt to not have Havenwise control the hot water and just the heating, that said the team at Havenwise are constantly developing this stuff and all this feedback is gold......  I personally would just add multiple target times as you have, I know my (I hate saying it "boiler) setup at the moment is 3 reheat target times, .08.00 so after we have used water, 16.00 just incase it needs a top up and 10pm to replenish as we would have used the shower in the eve. Once I have a HP in my new home I will probably run the DHW 24/7.

@hcas perhaps a built in option to run the DHW 24/7? or selectable minimum temp of 37 so thee is always something left in the tank until good electric tariff time?

Posted by: @jamespa

↑

I'm fairness to Havenwise the logic of dhw heating is tricky. 

Many people including me have their dhw deliberately set to reheat once per day only.  In this case the hysteresis acts only to stop reheating if the cylinder hasn't cooled sufficiently to justify it.  It seems you prefer DHW priority mode where the dhw reheats as soon as it has dropped below a certain temperature.  That's fine but for many this is needlessly inefficient. 

Which is better depends on usage relative to tank volume, the position of the sensor in the tank, and the times and patterns of use.

Havenwise know none of these although with some logic I think it may be possible to deduce the first two from the energy demand to reheat.  I can't see how they can ever deal with two girls unexpectedly taking long showers at random times, other than revert to DHW priority which of course frustrates any attempt to optimise cost!  It will be interesting to see where they go with this.

Yes, the priority for now is to best match the usage patterns in the house.  There is a demand for evening showers as well as early morning ones, and it was fortunate that I was able to pick up on this very early via an (unplanned) weekend schedule of showering.

In fairness, Havenwise also don't know the state of the battery charge or solar generation at any point in time, so their logic can only deal with the information they do hold.  It's then down to me to tweak the settings to get the most efficiency via the setup I create.

Posted by: @ashp-bobba

↑

@sheriff-fatman Just to add to what James was saying, I think you can also opt to not have Havenwise control the hot water and just the heating, that said the team at Havenwise are constantly developing this stuff and all this feedback is gold......  I personally would just add multiple target times as you have, I know my (I hate saying it "boiler) setup at the moment is 3 reheat target times, .08.00 so after we have used water, 16.00 just incase it needs a top up and 10pm to replenish as we would have used the shower in the eve. Once I have a HP in my new home I will probably run the DHW 24/7.

@hcas perhaps a built in option to run the DHW 24/7? or selectable minimum temp of 37 so thee is always something left in the tank until good electric tariff time?

I couldn't see a way to detach one element from control without the other, but perhaps that's just a case of me not looking closely enough.

I did mention to @hcas that I was planning to post a user experience update within this 'blog', as I suppose it's now becoming.  I'm hoping its a bit of useful feedback for them, and also gives a bit of insight for a potential user of the system to know what to expect and plan accordingly.

Hopefully, it's clear enough to anyone who reads it that the overall perception of the system is positive.

@sheriff-fatman , @jamespa , @ashp-bobba : Thanks for all the feedback and input! You touch upon the fact that DHW (domestic hot water) seems simply on the surface, but is actually quite complex. There are so many factors at play, of which you already named a few. 

We are indeed continuously evolving the logic and the functionality. We've already discussed many times a reheat function (or minimum DHW temperature function). The challenge is that most people don't want / need a reheat function (to the earlier point of @jamespa), we don't want the reheat function to become the default (because it seriously reduces the cost reduction potential), and a combination of a schedule with a minimum DHW temperature quickly becomes quite complex. Anyways, I'm rambling here a bit, but just to show that we're continuously thinking through these topics internally as well!  

Btw, you can see 6 DHW setpoints in @sheriff-fatman 's screenshot. This doesn't mean there will be 6 hot water cycles in the day. Hot water cycles will only run when they are actually needed. For instance, only 2 were needed today, one around 7am and one around 5pm.

@sheriff-fatman Perfectly clear it was very positive, like all these new systems they get better with every update. We are starting to install Havenwise to our systems and want to see what it can do in every scenario, take that experience and see how we can make that work for all of our clients. Once we have a few in we will review all of the experience from each HP owner.  

Posted by: @hcas

↑

Btw, you can see 6 DHW setpoints in @sheriff-fatman 's screenshot. This doesn't mean there will be 6 hot water cycles in the day. Hot water cycles will only run when they are actually needed. For instance, only 2 were needed today, one around 7am and one around 5pm.

I should perhaps have mentioned this in my post, as I'd factored this in to how they are set up.  There's an expectation of a temperature drop of 5°C on the morning cycle, which should only be triggered by multiple showers (as this morning, when my wife and I both took them).

The logic of a midday setting is that this will likely be a peak time for any solar activity and with a good amount of charge in the PV system available.  The later one's are in expectation of kitchen usage in the early evening and potential evening showers, after which the cold water will be naturally heated when the overnight cycle kicks in.

My wife's nephew has installed a smart shower which can be time limited (and presumably monitored/controlled) from his phone to deal with the excessive length of shower issue (which to my mind is the root problem and, dare I say it, very 'first world'.

Just saying.