JohnMo

Opened up the box, and found the fuse blown. So first job replaced fuse and check over the wiring to the box. Other than that without desoldering it cannot be taken apart easily. Big heat sink and fan at the top

My second PV diverter has now given up. Coming to the conclusion the multiple switching isn't good for their health and they are cheap rubbish. Not willing to part anymore cash on them. So looking to go basic but smart enabled. Control scheme will be something like x kW being generated, battery state of charge is higher than x%, run full 3kW into immersion for 30 min recheck and run again etc Can do the control via Shelly and home assistant - have both already. But need a relay that is happy switching 3kW reliably - anyone got a recommendation? Not sure I would trust a Shelly do that directly Does the control sound feasibly?

Think the important bit is to drop down, that kills any thermal gradient which leach away heat from the cylinder. If it's pipes at the bottom of the cylinder I wouldn't bother, as that area takes in cold water when you open the tap so is cold quite quickly anyway.

Can't you just change the max flow temp setting down from the default 82 to something lower. Condensing mode stops when return temp exceeds about 54 degs, it has no care what the flow temperature is, so if you are getting a 10 Deg dT across your coil you could just the max flow temp to 64, have condensing, good efficiency all year. So now your boiler runs WC in heating mode, and up to a max defined flow temp (by you) in cylinder heating mode.

Why do you need to flip setting between summer and winter? You should be able to define an outside temperature (if doing WC) your boiler stops doing heating, then it just does DHW. When you are doing PDHW, you are really operating your boiler more akin to a combi boiler, your diverter valve is outside the casing instead of inside. The heat exchanger is a cylinder instead of plate pack exchanger inside the boiling casing. So the heating is just treated differently to CH and different heating parameters. But you can do each independent of the other. So nothing to change between sumner and winter.

Couldn't you do that with a smart relay and or a timer thermostat? A lot of heat pumps have a double set point, usually activated via a zero volt contract. I have my heat pump set to 27.1 degs flow, as my base temp for WC and the second set point at 30. WC is normally based on the start point of 27.1, when second point engaged the WC base temperature jumps up to 30 degs. So use a simple timer thermostat, when not calling for heat pump runs at base temperature of 27.1 for WC. When calling for heat runs at base temp of 30 for WC. Thermostat set to 20 during the day (knowing WC normally keeps it at 20.5) and at night (E7 period) it targets 21. That way if I have plenty of solar gain in the day I am not running the house too hot. So during cheap periods, use the thermostat to ask for a higher temperature activating the second set point. Also use a smart relay to activate second set point when producing xkW from PV, battery is above x SOC (state of charge) and outside temp is below x degs. Simple home assistant automation. When the sun's out and battery is pretty much charged I can buffer the floor for a couple of hours for free, when in E7 period I also buffer the floor.

An example of how it looks, we have a fan coil in a heated summer house, with very different heating and heat loss profile to the house. Flow one flow temp, no mixers. This is overnight, orange line is the supply temp from the heat pump. The other two lines are temperature in the house and summer house. Outside temp dropped to 5 degs. The spike in the orange is starting to do DHW.

Not as far as I am aware. Clip the pipes to the insulation - screed, done.

If you running WC it's pretty difficult to overheat any part of the house. Unless you're curve is way out. Local rooms overheating via solar gain pretty much self manage anyway, delta T between floor and room decreases and output from floor stops. No controls needed. You can use your floor to buffer loads of heat and it really has very little impact house temp (to a point). Thicker the screed the easier and least fluctuation on house temp. With gas boiler I routinely heated whole house floor for 6 hours and lived of the heat for the next 18 hrs, about 1/2 Deg house fluctuation. Heat pump isn't powerful enough, to do that on a cold day.

On the MCS certified website Domestic_HW_cyl_selection_guide.pdf

1. Yes 2. No you can't do that and claim grant. You have to be merrily ripped of first. Pay many thousands and the grant just vanishes 3. Installed ASHP is vat free anyway, new build or otherwise. If you go under MCS and the grant the cylinder size is defined under a minimum size by MCS rules, can't choose a smaller size. I would price up yourself and then get a grant based quote. Why limit yourself to Vaillant? Buying again I would go Panasonic.

Today no sun, UFH not gaining temperature, very slight fall. Sunny side of house is timber clad on a 100mm ventilated cavity, but sunny side of house also has 50m² of glazing. Walls are externally insulated ICF. Although heat losses would be slowed down, air temperature rise through solar gain is at play. Floor just soaking it up and showing in the slight uplift in UFH temperature.

Methane? What do your drawings state? Is you house wrap certified for roofing applications? Suspect the joiners are wrong.

If you have choice of finding spaces for radiators or everything hidden, I would go everything hidden. Plus lower flow temperature for better efficiency. Wet UFH everywhere, plus you could add electric (in addition) in ensuite and bathroom, if you want if hot underfoot, and for off season heating. Add electric towel rads for bathrooms either way. You don't need much piping in the floor for UFH to work (if well insulated), we are on a loose 300mm pipe centre and it works fine

We went for borehole for various reasons. We pay way less than normal water. Think we paid about £140 for the annual service. The steriliser is just a light in a tube, bulb gets replaced as part of the service once per yearq. Our council tax water element of the charges is £500 plus waste water of £560.

Look at the data sheet and look at m² coil area. I just used an Ideal one 210L slim line, was about £800 last year. There are plenty of options out there. Or take a look here https://www.cylinders2go.co.uk/product-category/renewable-energy/heat-pumps-cylinders/?_gl=1*1ttl432*_up*MQ..&gclid=Cj0KCQjwmt24BhDPARIsAJFYKk3KvzDtUhGD5_9hmadZrcLf87Wv0TgcqsSxCr7QIu5Lmp0Sgy3PhBYaAniOEALw_wcB Will reduce reheat time, plus as more energy is transferred to water the return temp drops more compared to a small coil, so you get slightly better efficiency from the boiler.

So at that thickness you will have most likely two layers of rebar. They are usually 50mm of more below the surface. So zip tie at 200mm centres to rebar. Nothing will float up. You have two opinions with UFH pipes fill with air or water glycol, water glycol less likely to float. Plenty of examples on the UFH section on here.

Or ask yourself do you need the actuators? You could just run open loop and weather comp. Set your thermostat(s) to about 24 so the actuators stay open all the time, noise will never come back.

Think it's more likely the ground workers will be wearing wellies during the pour. How thick is your raft concrete? Confused by the comment on wet rooms?

We just did self storage in shipping containers x3, loads of house stuff in 2 of them and a car, 2 motorbikes and garage worth of tools in another.

Nothing to recommend. But look at noise also that varies between makes and models.

Couple of things Low flow temperature is required to get a low running costs. At 70W/m2 you will need 100mm pipe centres, even then the flow temperature is likely to around 40 degs or above depending on floor covering. Zones and loops are different things, loops are just circuits of pipe, while a zone is a controlled area of heating with its own thermostat. Lots of zones isn't the best thing for a heat pump efficiency and will drive you to a buffer. Also the insulation under the floor isn't the best for UFH will likely lead to excess downward heat losses, especially at elevated flow temperature. Not sure I would go with either the vendors you suggested. Get the whole heating system designed by your heat pump installer. Get them to do it as part of the grant.

It depends on pipe schedule (how thick it is) as pipe size is stated in nominal dimensions. Take a look below. https://www.valvesonline.co.uk/free-flange-tables?srsltid=AfmBOoqG7T3lPn0niO-55d0uNIKyHb0fiw_B9U79sEyC9H4moDn7wnUL

The important bit about extractor missed by many is the importance of the distance the hood is away from the pans. The further you are away the harder the fan has to work (as in higher the m³/h). Look at the instructions and set it the minimum acceptable. It will then work better at lower flow rates. To put flow rates into perspective 500m³/h is replacing the whole air contents of a 100m² house twice per hour. A small dMEV fan and the hood on recycle mode instead of extract, may do a better job overall. For normal day to day cooking you would not need to use the hood at all, only for smelly stuff.

The bigger your heat transfer area in the cylinder (the coil) the easier the heat source (boiler, heat pump etc) can heat the cylinder. A normal gas boiler cylinder a has a very small coil and requires high flow temperature. But I would Buy a the smallest a Panasonic heat pump you can get away with. Don't bother with the grant. £2.5k, you need a cylinder anyway, heating system sorted.