JohnMo

With battery, some extra PV and E7, when compared to gas heating, and no battery, I was a lot cheaper. But the kWh used was way more than it should have been. So would like to run as it should be, low and slow, single zone, zero controls, straight WC. See how it goes.

We have two Titon units neither are PH certified, there is nowt wrong with them. Could quite easily have chosen a PH certified one from Titon, but it didn't suit out needs flow rate wise. I would really doubt that.

Ball valve just treat the same as a piece of pipe, if it's 100mm long just add that to the pipe length Diverter valves are different they have a pressure drop and some can be quite restrictive. Same for strainers and strainer ball valves. Think you maybe overthinking all this, you don't need to detail the last Pa drop in pressure. Aim for a reasonably low pressure drop. No gate valves, just ball valves for isolation, at least a 28mm diverter, a strainer, that's about all you have in the system. Keep everything simple. I would just plump the whole lot in either copper or Hep2O or a mix of the two, where it best suits the run. Copper tails on any compression joints, the transfer to Hep2O with a straight coupler. High points will need a bottle air trap to bleed air, just need a 28 by 15mm tee for that. Low points need a drain. If you want a low pressure drop diverter an ESBE is fine, I just use a Honeywell 28mm it's fine.

Not really as @Dave Jones said earlier he had cooling on MVHR and it was not good. Ventilation and cooling are different animals, with very different flow rates required, I wouldn't mix together in one unit. Plus if one side breaks down you loose both. Cooling via your UFH loops in not too bad.

On mine no, they are factory set.

MVHR summer bypass works in hot periods when outside air is cooler than the air being rejected. Therefore bypassing the heat exchanger. If the house is cooler than outside it should operate in normal mode. So cool the incoming air via the heat exchanger.

That looks the right unit from mitsubishi. A ball valve is just like open pipe when open, so no restrictions.

This is true but you need to look at what occurs at the heat pump also. The dT between flow and return will increase. The ASHP will try to maintain flow target and dT. If the target dT is 5, and you start removing more heat to play catch up, the dT could move to 6 or 7, the ASHP trying to manage dT will allow the leaving water temp to fall below target. The ASHP ramps up power to full power to try and get to target flow temperature. Question - Can it actually deliver the required power to catch up? Possibly on anything other than design outside temp. But likely to run a full load until it gets back to equilibrium. Will you take a hit in the wallet - most probably. Do you need a buffer to if messing with some room on set backs, maybe. Will it hit your wallet with an uplift of flow temp to have a buffer - probably. I ran my heat pump last year deliberately on this basis, with UFH my set back was 0.5 degs, because heat loss was slow (well insulated and thick screed). I did this way to make use of cheap rate electric. Looking back I used loads of cheap electric. This year it will be straight WC no set backs, the heat pump left to tick away on WC. Last year in summer I ran the ASHP in cooling mode it ran for 3 hrs straight in the morning and the same after DHW in the afternoon, it spent the rest of the time off. Used about 4 to 6kWh a day (free from PV). Made some changes now have had the heat pump running continuously for 10 days, setting is basically if the return temp drops below 19.6 degs, the heat pump compressor starts. It runs 10 to 15mins and the depending on sun and outside temperature the compressor could stay off 30 mins or 3 hrs. Using about 2 kWh a day. Getting a cooler more comfortable house using a between 1/2 and a 1/3 of the electric. Slow and steady well setup is nearly always running at low loads.

Check the internet most are out there somewhere

I would get someone to check. Try and find the manual see what it says.

Correct Be careful as different manufacturers label differently. You need to look at the datasheet to make sure it's output is ok at your lowest temperature. Would question your design basis. It's more normal to have -3 outside and 20 to 21 inside except bedroom at 18. You need head room to do hot water. Allow 3 hrs. So working with 4.2kW, 4.2kW x 24hrs, then divide that total by 21 hrs, this should give you the size you need. Replace the 4.2kW with a better design basis. They don't restrict flow so zero.

The white vertical pipe belongs to your your gas supplier or the gas network supplier. To move is few stages. The network will have meter move forms you complete and pay a chunk of money to them. They make an appointment. You then get your plumber to disconnect the house from the meter. Network team arrived, move meter and replace pipe as required. Your plumber comes back to replace or run the house gas pipe and does commissioning checks. Budget a month or two from filling form in to being commissioned. All work can normally be done in a day, just getting everything aligned takes time.

They are pretty quiet, and WAY better than trying to sleep in a hot bedroom. My wife has one in her massage room where she likes silence, and doesn't seem to bother her. We have a Myson iVector. Winter you most likelihood will not need them. In use during summer the cool should fall to the ground floor, aiding the UFH which is also in cooling mode.

Sorry have you been anywhere near an MVHR unit? Have you tried to remove the heat exchanger, they are a really tight fit. Why to ensure there is no bypass between sides. Not sure how anything would bypass the between inlet and outlet. Testing for a bit blocked, is called annual maintenance. Removing the HE to flush through and remove debris etc.

That is the best advise. They will take the same flow temp as your UFH, so no mixers are needed. Run everything from the ASHP circulation pump, all as a single zone, no room thermostats needed.

No, your house heat loss is what it looses. If you just have UFH and no radiators it still looses the same amount of heat energy. Radiators everywhere and no UFH it still looses the same heat energy. Put in provision for electric panel heaters in bedrooms. At 180m² house and well insulated, your heat loss isn't going to be much more than 3kW, so you should be on the smallest heat pump anyway, any bigger than 6kW, welcome to big bills from short cycling.

That's not how MVHR works. Extract air only goes outside, it goes via a heat exchanger, air going out and air coming in, are on different sides of a heat exchanger and never mix. Air taken from the kitchen ends up outside and cannot go via other rooms or be distributed around the house.

So tell us about a normal (well maybe not that normal) house that is pretty airtight, has MVHR, triple glazing, ASHP, also made of ICF, and how the hob and using it. actually requires a ducted extract. What advantages we get to IAQ overall and for the 30 mins a day you may spend cooking? Most kitchen cooking hoods are set way to high from the hob to be effective, either at extracting or recirculating. So in most situations the bad stuff just bypasses the hood anyway. Main difference from anything commercial, is the fact no one spends that much time actually cooking every day. So circumstances, cooking temperatures are not compatible. Understand the need in a commercial kitchen, but not sure I follow the thread in a residential property.

Don't be caught with the installer adding 10% to his materials. When you are buying lots of sheets of plasterboard for example, that can be quite a few sheets that do not even get touched - been there got the expensive tee shirt.

What do your drawings say? That's what the builder should follow nothing else.

The sap report has all insulation between the rafters at 40mm thick.(Layer 3) Then a layer of 150mm insulation below that is layer 4, there are no rafters or wood present, so this must be below the rafter. There is no insulation above the rafter. Layer 5 and 6 are the wrong way around?

Just paint the ceiling near the sofa a slightly darker shade of brown. Now you are finished. Here to help 🚭🙂

Perhaps you could heat the whole house from the oven? 😜

Not that I noticed. As said we barely use the cooker hood, so regen are few and far between.

Leave them alone, all wood splits as it dries out. Look at any old oak house.