ashthekid

To be totally honest I am probably running the ASHP as a traditional gas boiler in that I'm heating up the DHW tank from 5am to 10am and then again from approx 2-4pm, off for the peak times on the Agile tariff(4pm-7pm) and then back on for a couple of hours 7-9pm. UFH I having coming on at 5am pretty consistently all day until 11pm which is when I drop the temp down below 20 degrees. I don't have all zones on though. I would say on average I always have about 6 zones totally switched off and during the summer I didn't have any UFH switched on for the months of May/June/July/August. This is the 2023 data I took from my OVO account before switching over to Octopus's Agile tariff last week.

@JohnMo Yes it does sound bonkers but there lots of extra rooms like 2 offices, Tv room, playroom, utility, 2x lounges, snug, hallway, landing etc so it very quickly added up. It's a new build within 200yr old walls so quite an unusual setup. Running costs are a lot more than I calculated that's for sure and during the build all the energy costs were constantly creeping up. We only have electricity and over there last two years we have spent approx £700 per month during the winter months and this summer that came down to £200 per month, probably mainly due to the benefit of solar panels, albeit a small array(10 panels) which I wish I had made larger now of course. And I'm really annoyed now that I did not notice the LLH was not the intended Clum one that I had agreed to.

I was told it was kind of essential on a system as large as this to boost performance and efficiency whilst also balancing out the flow rate when there is more than one circuit. It definitely looks made up rather than off the shelf which I wish I'd identified before as the original quote from the plumbing company stated a Culm DN25 low loss header which I believe is a brand selling off the shelf units. So our only source of heat is with our Hitachi Yutaki S 8.0 split system ASHP which I was told could handle a peak load of 13.5kW ASHP. UFH throughout downstairs and upstairs via 4 manifolds (2 up and 2 down). 400l hot tank. 6 plumbed towel rails. This covering a 5 bedroom, 4 bathroom home. 19 thermostats covering approx 380sqm. We have a large open plan kitchen lounge dining area which has a glass wall and bifold on one side so I know we have some serious heatless from there as well as some big air gaps around some oak trusses which I know doesn't help. The whole house is run on electricity so no gas or oil.

Hi, I have a relatively new ASHP setup which is approx 2yrs old and at the beginning of last year I started noticing a drop in pressure which I was having to top up every month or so which didn’t bother me as I couldn’t see if there was a problem anywhere on the setup. I have since discovered a very small slow leak from the low loss header which would explain the pressure dropping and maybe why the whole heating system isn’t working as efficiently. I’m wondering what people’s thoughts are on this? Do I get it re-welded or replaced like for like(although I support it was built on site with the amount of welding I can see on it) or removed or replaced by a different setup? Here is a photo of it attached. I’ve just been quoted over £1000 for a replacement(labour 3hrs & parts) which I thought was quite punchy considering a LLH is only around the £200-350 price point.

My logic behind the set point for UFH being 43 was that if the DHW is set to 45 and thats what the ASHP is pushing for then i may well use that similar temp as the same amount of energy is going to be used to reach the higher temp anyway. Is it not sensible to just have them set at the exact same temp each?

Yeah the air gaps are definitely annoying and affecting the large open space room which has tall ceilings and the exposed trusses. That's the toughest room to heat by far and you could really feel it again last night with the temps that bit lower again.

@PhilT I believe it’s the new LCD controller on the Yatuki S model which also includes the integration with the Hi-Kumo app to control the system via WiFi. Well it turns out the reason why the UFH was off was this app had somehow switched it off and I bizarrely could not override it on the controller itself until I went back to this app. It’s a terrible app anyway with it being so basic you literally can only switch the system on or off. Since switching it back on I have UFH back. @sharpener Those are set temp points on the Home Screen. What temp do you suggest I set the UFH set temp too? I have adjusted it to 43 now as I’m noticing our bills are really starting to shoot up now the outdoor temps are dropping. I’ve been hitting £30 a day recently. And during those really cold nights when the ASHP struggles, is there a backup or addon that could be put in place for me to switch like you would an immersion heater on a hot water cylinder? @mike2016 suggested a Willis heater. This sounds like a good option.

It’s constantly saying Demand Off for some reason.

To be honest the UFH has been working well and noticeably hot to touch when on and this has been in unison with the hot water cylinder as well. I didn’t think there was a priority feature when timings and things were setup - I assumed you could heat both at the same time or whoever you like. It hasn’t been an issue up until last weekend when we noticed the floor was stone cold. It obviously felt a lot worse when the cold snap happened and really made me realise something was wrong. I haven’t changed any settings to make this happen so I can only assume something like an actuator valve(or Hitachi flow switch controller) has gone as I can see the manifolds demanding heat(from the lights on), I can see the thermostats are calling for it too but where the hot pipe comes out of the air source(split system) indoor unit it splits and the hot pipe continues one way to the cylinder but notice it does not go the other direction where I assume the control switch is. I can see on the Home Screen that the UFH(labelled Circuit 1 in the photo) is “off” but I couldn’t find anywhere obvious in the settings to switch it on. DHW is showing as on which would explain why our hot water supply is working fine. Long shot but I must have switched it off somehow by accident but I honestly don’t know how. I’m one of those guys who doesn’t really like to fiddle around with settings too much in case something like this has happened. @sharpener I have had the UFH coming on at 4am for months and DHW at 5am so the UFH should have received priority already. I have a 16kW Hitachi Yutaki S split ASHP system with a 400l hot water cylinder. Outdoor unit: RAS-6WHVNPE Indoor unit: It covers approx 385sqm through 4 manifolds(2x on each floor). Occupancy 3-5(this varies as we have people stay a lot).

We have a recently converted old building with plenty of insulation (albeit with some gaps around the oak trusses that provide what feels like ice cold air con at times). We have a new ASHP and UFH setup which has been working fine but definitely pricier that expected which has disappointed me. My question is, and I knew to not expect great efficiency of the ASHP during anything colder than -2 like it has been the last two nights but my UFH has totally stopped heating up despite us still getting hot water through the taps. The system was suggesting the ambient outdoor temp was -11 last night. The hot water cylinder seems to heat up without any issues but the manifolds that provide the UFH are cold to touch and I’m sure they used to be very warm. With the hot water cylinder am I correct to assume the target temp is topped up by a backup immersion heater element and that’s maybe why that keeps warm. But what about the UFH. If the ASHP is struggling to get to the desired temp is there some sort of backup immersion heater for UFH that or is that just wishful thinking? What do people recommend I do as otherwise I feel like we are going to struggle to heat our use in winter. This is our first winter in the property so I just want to be prepared or add on some sort of backup system to help. we have no gas in our village and it’s too late to add an oil or LPG tank etc so it needs to be relatively small electric backup system in our plant room which is pretty cramped as it is. Or should my ASHP be doing better to achieve what it’s designed for? I’m struggling to work out if it’s actually potentially broken or not.