JohnMo

Are all your radiator lock shields closed too far, so little or no water flows through system? Are you certain you don't have a valve closed somewhere?

Not sure what you mean here? Disqualified from what?

Maybe for the house AND outbuildings. You can easily run both from a single heat pump.

Dust in the duct etc. I had a Dyson once lasted an hour sucking up building dust (motor failed). It's super fine and gets everywhere. A Dyson is small change compared to MVHR. Another dehumidifier?

A HiSense 4.4kW will come down to 1.8kW at 7 degs, so add a 50L volumiser, you will cycle about once per hour. £2100 delivered, plus you can claim the vat back on a new build. So a little over £1800, volumiser £100 to 150. A heat pump cylinder sized at 45L for each bedroom plus 45L, around £1200. MCS as @Nickfromwales says, will want a standard design, so radiators in each room etc. And still charge an arm and leg. If you size you fan coils correctly your flow.temp will never exceed 35 degs for heating, so you should get a scop of 4.5 or better.

Yep, our longest over hang is about 4m. Basically fixed to two wall plates. Whole roof was engineered by posi supplier and approved by structural engineer. Each end of the house has a 6" steel pole anchored to a big block of concrete, as additional hold down

Trouble with mixers is they mix, so quite a lot of return water goes around the loops again, so inlet water flow rate can be low. So low flow rates a 3kW heater, it's possibly boiling the water.

2kW doesn't sound a lot, but that's 48kWh a day at your design day. So would be pulling the cylinder temp down pretty quickly. Then you would be getting a rubbish CoP most the time. Not sure having the heating taken off the top would be that wise, as your DHW would always be cold. Think if you are going thermal store I would go proper thermal store. Have store as a pressure vessel, charge direct from ASHP, so no coils so heat transfer is 100% efficient. So if you store at 50 the heat pump only has to 50 degs flow. Take CH direct from store mid way up and return to bottom. Then have DHW via plate heat exchanger. Size at about 3-400L.

That shouldn't be the issue

What does your piping look like from ASHP to UFH manifold? Length and pipe dia. How long is the plastic pipe leading to the Wilo pump? The isolation valve on your Wilo pump looks to be a reduced bore, which will not help things.

So what is the difference between this and various emulsion paints, say a kitchen or bathroom which is more water resistant?

Brink do a system based around a normal MVHR unit. Basically they dump the supply air in the hall, similar to PIV supply only system. You do need to duct and extract from wet rooms. And depending on room layout you may need internal fans or if routing allows duct to some dry rooms. I read about it first on Passivhaus website. But search for cascade ventilation or cascade ventilation with heat recovery. You main thing you need to do is visualise where and how air moves about the house to make sure all areas are covered.

Our 12 degs roof is covered in the stuff, some off cuts have been sat outside for 5 years now. Not covered allowed to get wet. It's still in pretty good condition, considering.

Deleted

Most places that do ventilation. https://www.paulheatrecovery.co.uk/product/filter-cone-125/ They help protect the ducting, the main return filter is there to protect the heat exchanger. But sounds like you will be a while before you are switching on. Don't be tempted to switch the MVHR on early, it maybe one step forward several backwards.

Hope it's better than decorating caulk, which shrinks after a couple of years and leaves gaps everywhere.

Would have thought so, but only up to a point, if you have big gaps everywhere, you may be fighting a losing battle. Have you done a pre plasterboard air test? Then you know where you are and can discuss what is is achievable with them.

I use cone filters in each extract terminal, you would be shocked how much dust they stop getting in to the system.

Locate as shown, drill holes through wall from extension low down (piping level), and excavate area under manifold, connect UFH pipes, pressurise. Then no joints needed etc. cover manifold with some insulation to protect it from bangs and knocks. Is it worth the hassle and increased expense to install boiler stove, piping and additional heat dump etc?

If you located the manifold on bedroom 2 / utility wall, you could takes pipes in to utility and terminate them on the manifold? Are you using the wood stove/boiler just for cylinder heating or UFH as well? Could you locate the ASHP nearer the utility? It looks to be on the south side of the house, which isn't ideal. Should be located out of the sun really.

You only need tiny amounts of water for defrost about 40L is enough for most heat pumps (except huge ones). Your min output is 1.85kW, so multiply by 20, do you only 37L to protect from short cycling. You don't need a volumiser with 60L.

Every man and his dog on that video. Good video through.

Gee this thread has gone mad, gone from what looks like an over calculation of 9kW, to people suggesting 3 phase monster heat pumps.

Flow is king with heat pumps. Excluding the mixer for now. Your flow limit comes from the flow meters on the UFH manifold. The flow added together of each loop is basically the max flow rate you can get through the system. Open each loop another 0.5 l/min, that will add 5l/min flow. To increase flow turn the black part of the flow meter on top manifold anti clockwise. If flow doesn't increase look at the mixer pump speed settings and increase the speed. Next - a later job. Your mixer isn't needed, it's just causing a bottle necks and unnecessary mixing. Plus it doesn't allow you to run weather compensation very well. You also need to run a higher flow temperature to compensate for the mixer valve. So get a worse cop. Two pump running cost you more money. I would be installing a single 5 or 6m head pump that does UFH and your DHW heating. Delete the mixer and pump.

We did something similar in our last house. If you want to keep the hand pump and make it electric. You basically need to take out the piston affair, from the hand pump so the pump doesn't pump. The pump then becomes an empty pipe. In the well, drop a submersible pump on a rope into the well water, pump size will depend on how many metres it needs to lift the water and flow rate needed. The outlet of the electric pump needs to be installed into the the pipe that leads to the hand pump. The original pipe that came from the well, to the hand pump should only have a single feed from the electric pump now, so will need to cut the original pipe or hose. So you need access to well and pipe that leads to hand pump. If have to make access not a small job. Run a hose.