Things didn't quite go to plan with the install... They can't start this week, but rather next week, so that's a whole extra week without heating. We've had to buy coal to keep the fire going because it burns through logs so quickly it's incredible. Hopefully that is the last time I'll ever buy coal.

We also had a bit of contract back and forth, a fairly hefty price uplift, and still no heat loss survey! They said that the one I sent them looked to a good standard so they're using that to design, and will do their heat loss survey afterwards. It seems a bit shady to me, but then again I know that's only because they don't have the time to do it at such short notice.

We agreed to upgrade the model that was going to be installed to a newer model. The one originally listed isn't even in Daikin's product catalogue anymore, so certainly a bit outdated. I'm hoping that it gives some basic statistics to work out COP. It's not entirely clear from the installation manual that this is guaranteed. I'm also in discussions over where the controller should be installed, as they have planned to shove it in the garage. I'm planning on running on weather compensation only to see how that goes, but I still don't want to be heading out to the garage to get to the controller, and also if it has the WiFi module in then I don't think it'll get signal.

I also got from the Daikin manual that if my heat emitters are radiators, which they are, then DT is fixed at 8C. Reading that has made me completely scrap my plans for changing pipes from 10mm to 15mm in my living room, since it should now allow much higher power output even if it requires a bit more balancing - 2.9kW with DT8 vs 1.8kW with DT5. I was under the impression that heat pumps always aim for a DT of 5, so it's worth checking a specific model if this comes up for anyone else.

Also we had to arrange our own radiator delivery and installation, and it might clash a bit with the ASHP installation. The installers don't seem bothered, but it's all a bit stressful, especially because no one has looked over my radiator changes list, and it could leave me without heating for longer.

Don’t feel too bad, I bought half a ton of Welsh anthracite last week to run my Rayburn through this winter. 🤣 

The pump has been in for over a week now but still hasn't been turned on, and won't be until next week because we've been having a nightmare installing the new radiators and we couldn't get it commissioned until the end of next week. It's getting quite chilly now!

The installers were originally going to set up the Daikin tank (which includes a buffer/volumiser) as a buffer, but I managed to catch it and they agreed to change to using it as a volumiser which was the original plan anyway. There's a couple of things I'm not overjoyed about with the installation, so I might have to work a bit to resolve these things. I don't understand why they attached the exterior piping with metal clamps directly on the piping as opposed to lagging first and clamping the lagging, surely that would be so much more effective.

I'm unsure whether I should by Daikin's Madoka thermostat to modulate the heat pump with weather comp, or just run on full weather compensation with my current thermostat as a limiter set to something pretty hot like 23C, with the idea being that I'd never reach that. I've seen a few ways online to connect my heat pump to my home automation system so I could do the modulating myself and save a few hundred pounds on a complex install of the Daikin thermostat which would have to be wired all the way to a living area.

What I'm really worried about is when the plumber changing our radiators fills the system up, will it just all drain out the freeze protection valves, or if the incoming water warms them up enough, will it just freeze inside the heat pump and break it? The frost is lasting all day at the moment, so it's a real concern. I asked the installers and they said they've never filled up a heat pump in freezing temperatures so didn't know what would happen.