JohnMo

Where are your ducts going - photo?

Go outside with a cup of tea and seat, monitor what occurs over an hour. If it's cycling a lot, you will be done and dusted in 20 mins. If you have a smart meter, you should be able see increase in electric consumption and how long it lasts also, monitor flow temp on the controller etc That is just nonsense really. In that case make sure the flow rates are matched on all pumps and both pumps run together. Do you also have an UFH mixer? I assume not. You can check by measuring the flow into and out of buffer on the bottom ports, that need to be the same if both pumps are the same flow rate. Your Samsung controller will be able to control various ways. Think one way is WC and it's built in thermostat working together.

Yes - look at cycle times. I found the longer the cycle time the better the efficiency generally. Every floor and house is different. I found a min on time of 10 mins was ok, but 20 mins was better. I have recently set my WC curve to 30-35 and use a 0.1 hysteresis thermostat. The heat pump runs generally at night and runs continuoisly for many hours. It then generally remains off for the rest of the day. Also make sure you don't have any small zones calling for heat, this can drive down efficiency as you get lots of very short cyles. Heat pump running isn't that black and white, although many will make out it is - stick it on WC your in the best place - not always true as the video above demonstrates

Ideal is made in the UK, which may have advantage for parts and support? Most heat pumps are good, the install is the important bit really Generally - Volumisers are ok, buffers avoid, lots of zones avoid. If the system looks very simple that is generally good. minimal install is heat pump, 3 way diverter valve to cylinder or heating system, one thermostat. Either run weather compensation or use thermostat on fixed temp of around 35 degs. A fixed flow temperature can yield performance benifits because it allows extended runs times and avoids short cycling. If installer suggests above 45 deg flow temp, move on to next installer. Cylinder size, two things drive this. number of bedrooms (minimum size), and life style (to make it bigger). There are two of us we have 210L and wouldn't want any smaller. If you have kids coming down the line, I would suggest 300L. Discussion on OVO over the last few days on here - have a search. But no thanks from me - based on their performance when I was a customer. Octopus may be a better choice.

Filters are wonderful things, I once modified a gas turbine filter system, on an offshore generator, moved from F7 to H12, eliminated almost all the salt from the combustion air. Turbine blades were failing in under 6k hrs due hot corrosion (sulphur, salt and high temperature). Couldn't get the sulphur out of the fuel, or change the temperature, so chose to remove the salt. When I left the company, the turbines had lasted over 20k hrs, no reported issues.

Sounds like a sensor issue. Looking for a feedback it's not seeing?

A low loss header, is just a hydraulic separation device. The flow goes in and out at the top, the return in and out at the bottom. If you are taking zone 2 off the bottom it's just getting the return water from zone 2. Think you need to post some photos Suspect the LLH is plumbed incorrectly.

Can you not just do it with block work, way easier if frame already there.

Not sure that is true with low temp heating. Would be true for high temp radiators. A 20 deg room would need 26 at top of apex, our floor surface temp not getting that high, so top of room cannot be hotter than the heat source. Other day was -5 and floor was at about 23-24. Just did a check with the thermal camera, the ceiling at the top of the room is 1 Deg warmer than the external walls. Did the other day when it was cold and not much difference either.

Yes agreed, scaffold during build. Not that bad really - use telescopic things Maybe true, but it's not bad once furnished. UFH so not bad really. Only thing that really adds to the heating is a wall of glass Wall lights and a couple of side lights - zero issues. Only if they go full height - or just don't bother. No difference to any other just plan ahead. Maybe a little more expensive, but not harder. Ridge beam and posi rafters Harder to insulate. Loft you just roll it out. You definitely need scaffolding inside to build. Airtight details are easy. Cooling is really dependant on glazing, and solar gain. Glazing - This time of year it makes heating easy.

Have you done the simple switch off and back on again?

We just added noggins between our joints, where needed. All done from below. The terminal/valve just slips in the 125mm dia plenum. You may have to remove later so no don't glue. You may have to upload some photos - no real idea what you have or why it's difficult.

Just did our living room for reference General room size is 6x6m, fully vaulted up to 6m tall. Fully glazed end wall comes out in V to project outwards a further approx 2m. Green area being idea, orange line is where we sit after clap test. Did a couple of tests with different results We don't have any issues of note, so unlikely to do the remedial work they recommend - at £3k for materials.

Two units made the install easy. House is 25m long and would have resulted in a few long double runs, these became short single runs. 2k, the 2x Titon units came from eBay, new unused for £250 and £320. Rest of the costs for duct etc etc.

Disconnect all the third party thermostats, you just don't need them. Tell.us more about the system, buffer no buffer, as much info as possible. Has the system been commissioned?

Really depends on how many you have in the house. We have 194m² and average room height around 3.2m, so 620m³. We are set at about 140m³/h or 0.24 ACH (2 people plus dog) and looking to reduce during winter based on humidity. Certainly when we have had visitors, so it became 6 plus dog, no issues then either.

It sounds like your flow switch isn't working on the DHW side. The flow switch should push the burner output to the max. Or do you have the settings just wrong in the controller and you have set DHW to 40 instead of 60ish. Heating and DHW should be different parts in the boiler logic. DHW setting be completely different to heating. Easy to set a combi to run a cylinder. And a way better solution compared to combi. Heat pump cylinder, will give 55 Deg water from 60 Deg flow temp in 25 to 30 mins (210L). You need a resister to move boiler from thinking it's running weather comp to not, it then flicks over to achieve flow temp set in the boiler controller.

Why so high, only Scotland demands that, and they are stupid, may make sense in shoe box, holding 4 people, but most other properties it's way too much. You are wasting energy, dragging down humidity in the heating season, for no good reason. Even Passivhaus only want 0.3ACH, which way more sensible. The fresh air requirements per person from PH is 30m³/h per person, while English BR is about 20m³/h. So 450m³/h would be fine, if your building for 15 to 20 people, otherwise...

Near but not quite 1 atm = 101325 pascals (Pa) 1 bar = 100000 pascals (Pa) atm value x 101325 Pa = bar value x 100000 Pa atm value = bar value x 0.986923

As long as always in the same direction. So 'A'

As you use the system micro air bubbles come out of suspension making the water volume smaller. Go around all the bleed points in the system and bleed any air out. Then reset the system pressure. Do you have any water leaks?

UFH requires a good amount of floor insulation to be cost effective - not heating the ground. We did a U value of 0.09. but aim for as low as practical. Aim for 150-200mm PIR or 250-300mm EPS.

I moved from OVO to Octopus, would I ever go back NO. Octopus - Not a single issue, that couldn't be resolved by picking up the phone and talking to someone in the UK, that was happy to help. You can change your direct debit easily with Octopus and see projected costs. OVO - I voted with my feet and moved.

We did vaulted in every room. Our lounge is 6m high with 45 Deg roof. All others rooms are 12 deg. It's very easy to do airtight details. Your roof structure can be a little more expensive and you have three options for insulation, between and under rafters, above rafter, or mostly above rafters and some between rafters. You have slightly more exposed roof area to the inside of the heated environment so a slight knock on heating costs - but nothing massive. You really want to heat via UFH, not high temperature radiators, as all the heat will end up in the roof. Do not install lights high up, other wise you need a scaffold to change a light bulb. Would I have normal flat ceiling - no way. When very high you need plenty of soft furnishings.

That's a Shelly H&T, within Home Assistant. Shelly own webpage is pretty crude. Batch charging is using the floor as storage heater, in basic terms. Charging the floor similar to storage heater in cheap periods. We are single storey, so no real upstairs.