JohnMo

If you run out of water 4 things to do Heat it hotter - needs more cold water to mix down to correct temperature - increases the effective volume of hot water Heat it more often - let it heat when it needs, to little and often. Reduce flow at outlet or time used, your using to much water Get a bigger cylinder - your cylinder is too small for your lifestyle or number of people in the house

Early start early stop with UFH just doesn't work, the algorithm is really designed for radiators not UFH. Same as load compensation useless with UFH. Never achieves the correct temperature at the right time. Tried it with Atag controls and Salus.

The difference between a LLH and buffer is purely volume of water it contains, both provide hydraulic separation. A volumiser is inserted in the flow or the return and is there to provide volume only, it does not provide hydraulic separation. With hydraulic separation you have to have a pump either side of the buffer or LLH - one for the boiler and one for CH and/or cylinder side The big pump is there because you have a LLH. Remove the LLH and the boiler pump will do the pumping. Trouble with WC is they have a glacial reaction time due to the low flow temp. You may be better setting to 20.5 except a set back period of 19.

Cascade MVHR yes. No heat recovery, but do not exchange air when not needed or do so at a minimum rate. Tickle vents open and close based on humidity levels.

Not sure the open thermostat one would have worked for you, as you have so many zones and suspect most will be open and closing UFH manifold loops. An opentherm thermostat would really only be any good in a central area doing all the heat control - single zone. Weather compensation You have a bunch of thermostats already installed and connected to your manifolds and mixers and pumps. The mixers will limit the lowest flow temp from the boiler you can use as there will be around 10 degs of mixing going on inside the mixer. My suggestion is to keep it simple. Leave UFH system as is, with thermostats etc Move boiler to 4 port configuration Get rid of the LLH and replace with a small volumiser say 20L that should fit in the same space as the LLH. The volumiser would be in the house heating circuit only. Remove the big secondary circulation pump, as not needed anymore Run heating at a fixed flow temp (not WC), but run way lower flow temp than it's run now, say 35-40, but run for much longer. Nearly all the benefits efficiency wise, easier to implement, your wife will not be asking why you bought all those thermostats.

Why limit yourself to MVHR, dMEV or MEV done well can be equally effective. You need to it on a humidity controlled basis, with humidity activated inlets, either trickle or through wall. The other option is cascade MVHR, very little ducting used, which is a little like PIV and MEV combined with heat recovery

I would say, any sun is bad, when heating is expected to be on - who cares about summer sun your heating is off.

Here is a thread I started prior to doing my ground array. Approx 4kW split into two. No way it would 60m without a voltage drip too big or huge cable. Ended up doing 4x6mm2 armoured cable to inverter, approx 60m away.

It is huge and running on speed 2, so not a small energy input.

Or could that be a volumiser, and do away with hydraulic seperation and additional system pump. Currently he has pump in boiler, pump the other side of the LLH, then one on each UFH manifold - lots of pumps.

Not really as they are all different. But a single zone system looks ok. I needed about 40L to keep mine happy, small volume equals short run times. You need to read install instructions to get the correct details.

Depends if it doesn't or does shrink really.

As it says in the video, normal caulk shrinks. So you end up with cracks every couple of years. Then you need to think about painting again. Bigger the gap the more it shrinks.

10% is a little low, just had a look at my EPC and 20 to 25% is a better value for the increased heating requirements for DHW in the 6 winter months, as an average, compared to 6 summer months, as an average.

Like most jobs simple enough, but time spent doing this, is time not spent doing other jobs. If your interested in learning all about it, do it yourself, if not really that interested get someone to do it for you. But make sure balancing and commissioning (with calibrated flow meter) is included and full payment not made until complete. Choose your battles!

Just keep your hand away from where you nail. My second day, I held the wood close to where I was nailing, the nail hit a hard knot and went at 45 deg, through my finger. A tad sore, pulling my finger of the nail. Good job I had some masking tape in the van, to use as a plaster.

Before you go the road of making mods Check your summer gas usage, add 10% to that usage, to account for the colder mains water coming in during the winter. That is your DHW usage, convert to a month usage. Any changes you make, will not change this figure. Now subtract the calculated monthly DHW usage from your winter gas usage. That figure is how much your heating is costing you. You could save between 10 and 20% on that gas cost, but if you don't like the feel of the house on WC you will save nothing. Do you maths. Is it worth it to you?

What lie they don't say anything really except it smart - smart just means internet connected. Highlighted bit says a radiator valve doesn't takk to anything.

Read a new article last night stating that the Octopus tracker calculation method was changing, so prices were going upwards quite soon.

I have stayed variable, rather than fixing and being stuck on a higher rate. All things being equal, rumours have it prices are due to reduce over the next two quarters.

Not really enough information to answer the buffer question. UFH is it zoned if so what is the smallest volume of water? How far from heat pump is the cylinder, it easy to run a cable between the two? Can you provide the minimum stated system volume required for ASHP? If more volume is required a volumiser may be a better bet. Basics are ASHP 3 port diverting valve - one way to cylinder (normally closed) the other side to UFH (normally open) Heat pump cylinder, ideally with 3m2 coil It is normal for the cylinder to use a temperature NTC probe to measure the actual water temp, although most can be configured to use a volt free on/off signal.

Out of interest what flow temp do you use?

Flow temp is related to pipe centres and output required. Timed heating is never low flow temperature, weather compensation can be and most likely.

The main difference between operating in weather comp mode and timed heating mode is floor temperature. WC floor will be cooler, this does several things itself. It self modulates output - the closer the floor surface to room temperature the quicker and more immediate the change in heat output. Heat output is a calculation of surface area and difference in room temp to floor temperature. The smaller the differing temperature the less the output. So room gets solar gain, floor gives off less kW of heat. This in turn gives the boiler a higher return temperature so it modulates heat output down to match. The opposite is also true, room cools, boiler gives a higher output, because return temp to boiler is lower. Setting the correct WC curve will automatically switch off and on the heating also, as return temp remains too high once you get to a given flow temperature - this point is adjusted house by house and is curve dependant. Radiators cannot do this nor can high flow temp UFH.

Load compensation is flow temp altered with respect internal temperature, (quite immediate changes), where weather compensation is with respect outside temperature (more an average outside temperature). Load compensation and UFH is not a match made in heaven - tried it it was awful, temperature yo-yo.