JohnMo

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 loosing 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.

Should hope so, they need to give you some for £5k for their smallest heat pump. Plus you have to pay extra for cooling! Mitsubishi is the most comprehensive, I've seen and I've seen a lot.

Don't rush to get running, especially while your still working on house, it will drag in all the dust etc - you don't want that.

You don't need volume in the cylinder circuit. Think it's because the water to water heat transfer is so good, compared to water to air on a typical heating system. But you calculate volume in the heating circuit to get away from any likelihood of short cycling, basic calculation, is you need at min modulation, min modulation kW multiplied by 20, assuming no tvrs or manifold actuators (any circuits with either are excluded from the volume in the calculation). That should be your minimum system volume, but more is better. The volume number in the manual is the volume needed to support defrost. If you need to add circuit volume stick in a volumiser, generally in the CH side only on the return piping.

The latest Viessmann ASHP do it slightly differently - on approach to defrost, they move an internal valve and charge a small buffer to about 50-60 degs and the whole defrost energy comes from that. Slightly more efficient to the normal.

Just the normal way, I just let the heat pump do its own thing - you don't need a buffer for defrost, you just need the minimum prescribed volume available, as detailed in the installer manual - you never did need a buffer, it just hang on from fixed duty heat pumps. Heat pump just moves the 4 port refrigerant valve to cooling mode, refrigerant does the defrost. Water circuit just provides the heat. It's only in defrost mode a couple of minutes. Attached from the other day when it was cold and defrosting. The attached is the temperature and heat flows. Green line is return temp (from heating system/volumiser), red line is flow temp, yellow is heat pump thermal output, blue area is electrical input. - no hat needed😀