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Pretty much, yes... Although a good starting point would be 50@-2, 37@15 - the 37 being chosen to keep people quiet about 'the radiators aren't warm'

There’s probably a minimum cycle time programmed into the daikin somewhere, and despite removing the call for heat, it still overruns. Have you googled those terms yet?

Well, if the flow temp is permanently fixed at 45 degrees, it isn’t running under weather compensation. I wouldn’t trust your installers, they might well have stuffed up the install as easily as they stuffed up the flow temperature.

I believe the ecodan supports control over modbus 485….. that’s your avenue into automated control.

@MarvinI see from the ecodan thread that you were able to reduce cycling by adjusting the differential stop temp, which way did you adjust it? Could you post up your most recent settings for us running the same ashp, it would be helpful.

I’m flat out at work at the moment but if I get half an hour this evening, I’ll try and figure out what data in what cell is causing the issue.

There is something amiss in your spreadsheet data because the heat load graph isn’t drawing properly, and the DHW side isn’t working correctly, hence why you are only able to satisfy 69% of your hot water requirement. The spreadsheet I uploaded was populated with all the values for my house, so the cylinder size was set to as closely match my 150ltr slimline as I could find. You need to choose a machine that has enough overhead to recover the required heat loss from the building in the period that it is not doing your hot water cycle. But at the same time modulate low enough so that it isn’t short cycling too much.

At Caleffi prices, I wasn't going to bother, but for £16 from AliExpress I thought I'd fit one.

I just copied what I saw on Instagram, seemed to make perfect sense to me to just have one valve at the lowest point in the system. The easiest way to eliminate your valves is to remove them and replace them with bits of pipe To be honest, down south, how rare are these edge case conditions that we fit these protection systems for? I can't remember the last time we had a power cut.

Please post the kWh consumption from your gas meter for the same period, and/or advise on your unit rate. £50/week is £7.14 a day - that's not a lot in 2022

Exactly…. The anti freeze valves are for the rare case where there’s no residual heat in the system, there is a power cut, and it’s freezing outside. Only then will they open and release the water to prevent freezing. They are the way forward, and you only need one of them, not two as specified by most installers. And you can get them as 1/2 mount direct from china for £16. I stuffed mine into a 28mm press T

You don’t need the mixed pump groups. The weather comp curve can be set for the radiators and then you can use a standard ufh blending manifold and pump for the ufh loops. Pick a brand that doesn’t require a hex module for a start, and choose one that includes the room controller in the box. There’s really no need to go spending all that much.

I give you the AliExpress special….. Caleffi don’t make a 28mm press fit one, but it’s easy enough to make up your own with off the shelf bits. Under £40 for the parts, I think the valve was £16, delivered.

The 6.6 is the figure for my heat loss that I copied over into that cell from the heat loss sheet. If you replace that with your 8.5kW value, the costings should make sense.

Call a heat pump company, not a boiler company… Speak to Chris at CoolEnergy in Grimsby if you want to talk to someone technical. I’ve just added a 5kW Aerotherm plus and a VRC700 to my basket on the first hit I found on Google, with delivery it’s under £4k - where are you getting the other £4k from? Give us a breakdown of your system design and we can see where you can make it simpler and cheaper. Onto the glycol argument - no-one should be using glycol in 2022, a single freeze valve is all that’s required. A decent monobloc doesn’t need an internal HEX unit, just get the flow and return into your plant room and hook it up directly to the system. A buffer allows you to run the heat generator and the heat emitter as separate systems, with a loss of efficiency. Lots of installers use them because it eliminates callbacks for low flow errors when an existing system with too many TRVs have all the heads shutting down. A buffer also provides a large volume of water for the defrost cycle. Personally I have a small house with a simple heating system and we never have any doors closed so have no need for any TRVs downstairs. I’m going direct from ASHP into the rads, using the modulating pump in the ASHP - if I have problems then I’ll add a LLH and put a separate fixed speed pump on the rad side. So yes, a buffer doesn’t make it super easy to throw a system in that will work. The ASHP sees the buffer and controls the temperature of that, the room stats/zone valves/pumps just see the buffer as a ‘boiler’.

Your other option is 16/15 press rad tails, but they are always chrome/nickel plated. And you’ve got a joint under the floor, albeit a pressed one.

My builder friends are doing block/block, 200mm cavity, steels partly in the cavity. Don’t underestimate the steelwork involved with repairing the column bases - I’m a welder and me and my structural steelwork friend did a bunch of columns back last year, plating 150mm either side of the ‘zone of decay’. By the time we were halfway through the horrible job, we both agreed it would be quicker and far better to do a cut out and splice on the affected columns.

You can tell heatpunk that a wall section is party/internal wall - It should be covered in the video somewhere, I remember doing it for my upstairs party walls. Yes, pretend that Paris is London, the software was only designed for countries in the UK so that's why there isn't any overseas geographical support.

Attached is the Freedom Heatpumps installer/specifier toolkit spreadsheet - you change the items in the blue cells. There was a video online showing how it worked, but that has since been taken down. Heatpunk can be accessed through: https://heatpunk.co.uk/home You will need to make a free account. A video showing how to use it is: 1451167288_2021FreedomHeatPumpstoolkitV3.3forallinstallers-Copy.xlsx

I’ll give you a link to the 2021 revision of the freedom heatpumps spreadsheet when I’m in front of my computer. It’s nice and simple to use. There is also heatpunk from midsummer wholesale, this is a web based system and you can sign up for a free account.

All heat pumps are priority hot water, that's just the way they work. If you have them set to DHW+Heating (or cooling) then the DHW will be satisfied first. You won't get those reheat times when driving a Unistor (or any other heatpump cylinder) with a heatpump. The reheat times in the Unistor brochure are based on the maximum flow temperature that a boiler circuit can deliver - I actually seem to remember the Unistor saying that 85 degree flow was required, at which point the coil rating becomes valid. Have you played with the Freedom Heatpumps toolkit? It has cylinder reheat performance models on there based on cylinder size and coil surface area. I've attached it for your reference. 2046225701_2021FreedomHeatPumpstoolkitV3.3forallinstallers-Copy.xlsx

Monobloc heat pumps have everything inside, you get hot water out of them. No need for an indoor heat exchanger. those pipes are the flow and return and carry the central heating circuit water.

Yep, I can program a change to the WC for a nighttime setback. The UFH will be slow to respond because it will be in 100mm of concrete, so the pump timing for that will need some figuring out.

No thermostat, heating is just on or off from the Cool Energy controller. If it’s set to dhw the tank is charged till it is satisfied, if it’s set to heating the weather compensated liquid flows through the rad and ufh circuit. Rad and ufh always together (ufh is one loop in the extension we’re building)… About as simple as I could make it. Will see how well it works when I get round to plumbing it up. Can’t see why it won’t though. EDIT: I'm rambling, sorry. The UFH and the rads work together, they are not zoned separately.

Please don’t just rip this out and replace it, that’s the standard answer given by ‘engineers’ who don’t want to be bothered with a bit of fault finding. Provided your outdoor unit isn’t a rusty mess that’s leaked all its refrigerant there is no reason to just replace it. I’d be replumbing it with a pwm controlled primary pump and a small buffer or llh. Sort the wiring out too, perhaps change the actuators for something more modern. You should easily be able to get this working nicely again.