sharpener

Thanks. Was directed at @Dillsue in fact! By coincidence I remembered I had bookmarked this useful demand calculator also from SSEN https://www.ssen.co.uk/our-services/tools-and-maps/demand-calculator/. Allows you to test out what you might get away with before actually applying. Your 12kW sounds very restrictive. WPD have let me add a 12kW(t) HP and 7kW(e) EV charge point on my existing 80A supply, I was quite surprised. Couldn't easily upgrade to 100A as have 16 sq mm meter tails going by unknown route through a 500mm stone wall.

Sounds like we had a close shave then, original FIT system has 2 x 2kW Stecagrid inverters, fortunately the panels are 16 x 230 W so exactly 3.68kW, installed under G83/1 at the time (2011) IIRC. Blimey, what DNO was that? Am only 200m from the substation but am still expecting pushback if I try for more. Have now got a total of 6.9kW so ATM I have lot of curtailment in the summer, would like to do my bit (and get paid for it).

Does this work when the car is fully charged? Doesn't Octopus need access to your car setup and so can tell?

Why is the edit window so short @jack? Comparable sites like the Arotherm plus FB page or https://camelot-forum.co.uk/ allow indefinite editing, and it does not seem to be abused in either case.

No, reliability. This is just one of several recent posts on the Arotherm Plus forum about duff Honeywell valves falling apart https://www.facebook.com/share/p/nqxrMWsS4CE7Uio4/.

Honeywell diverters in particular have had all sorts of QA problems in recent years. Installers seem to recommend ESBE valves for anything over about 5 kW.

I believe Vaillant Arotherm plus are similar, default also -60. Not sure about max, ?-120 DM.

Further thoughts following a query I posted on the IET Consultants discussion group in an idle moment. I didn't get any more pointers on input filter design but though it worth a try. One reply suggested a power factor correction capacitor might help but I am doubtful. Another suggested a circuit to minimise the inrush current. But there is already a built-in soft-start facility in the VSD, what delay is it currently set to? Playing with this might buy you some more margin. Did you ever check that the motor is the 230V 3ph variant not the 400V? There is also a note in the manual about letting the motor run at full speed for at least 60 secs to calibrate the drive. If as I read elsethread you have an issue with acidic water then you might want to consider a plastic or stainless steel body for the pump not cast iron. There is a "polymer" version of the DAB pump, the JETCOM 62 but it doesn't seem to be readily available in the UK. So maybe s/s after all.

Thanks guys. Plumbers have in the past seemed quite happy to fit a Hepworth bladder trap onto my soil stack at first floor level for a boiler P & T relief. But it seems to require quite a head (>2m) to open it up, this caused the D2 drain line to back up to the tundish. So I relocated it to the bottom of the soil stack but it still does not drain freely. IIRC there are some combined tundish and waterless traps available now, perhaps this is the way to go. Ideally it would have an outlet for 22mm D2 not 32mm waste pipe, is there such a thing?

I think if the appearance is going to be acceptable you will be OK, particularly if they are both based on the same resin polymers. Most of the covering power in a paint system is in the undercoat, it needs UV protection though which the varnish will provide. We had a continual problem with a damp stain bleeding through on a chimney breast. International Paints'(*) Stain Block was completely useless but two coats of Ronseal matt polyurethane fixed it and would take matt emulsion on top. * makers of the famed International Yacht Varnish which says on the tin "not suitable for exterior use".

A carvel-built wooden boat of that size would have thinner planking, but also internal frames of some kind to resist the external pressure (so the fastenings would not be under tension). Also dinghies have reinforcement round the "rim" by way of gunwales or decking, and are generally curved, both of which which prevent the sides from bowing in. So I think you are right, some structural calcs might be in order to see if lengthwise external ribs would be a good idea. If the sides bow out it will also tend to peel apart the corner joints over time. Not easy to tell but to me it doesn't look to be very generously proportioned for 2 x 75 kg people.

I have got express permission in an AONB as HP is too big for deemed PP. South Hams DC (Devon) have applied no conditions in their Decision Letter about noise or anything else. Their Planning Officer's report includes only the following about noise Environmental Health Section: We have considered the application and the proposed make and location of the heat pump. The pump is a low noise pump with sound pressure level at 3m being around 36-38dB. The nearest neighbouring residence is further away than this and there would be no direct line of sight with windows to a habitable room. Therefore we do not anticipate that there would be any unreasonable noise impact from this unit. The statements about the neighbouring house are not entirely accurate, but work in my favour. I said in my application the installation would comply with the noise requirements of MCS020, my calcs show on a strict interpretation this might require at least a partial screen. I do not know where they got the 36 - 38 dB from, the data sheet I sent with the application has these noise figures with a picture that only applies to the smallest sizes. For the 12kW model the correct figure at 3m would seem to be 42dB(A), and even at 5m (which is just meets) it is still 1 dB over the 37dB limit. However I am not complaining.

PVGIS is your friend.

An update before you are next on site @Hastings in case it affects your planning. There have been no further responses from the Victron forum so I have done a bit more thinking about possible harmonic filters to fix this. The VSD manufacturer does a 50A filter <EMC Filter INFILT-M501> but it is £235 plus shipping and VAT. And filters that are too big may not be effective IME. I have actually got some sample toroidal choke cores which might well serve as the basis for a series filter, but annoyingly I cannot find enough design information, there is some stuff on the web e.g. this article and this one but mostly intended for big industrial applications so I have no way of knowing what component values would be correct for a small VSD. So we are back to the thought of replacing the pump with a smaller, single phase one. The automatic Steelpumps X-AJE80B would be good, but any of the other three mentioned upthread would also do with a suitable pressure flow control. They all have a suction lift of at least 7m which should be enough even allowing for 1m head loss in the suction line. As I wrote previously so it all depends on whether you want to stick with Steelpumps, go for something that also has spare parts availability and the best suction lift (DAB), for the lowest power consumption but not repairable (ST) or for the really cheap and cheerful option (small Clarke). Given the price of the Steelpumps option and that the rest are quite close I think my favourite would be the DAB62 e.g. from here, I see they also stock the Clarke controller which I have found works fine. HTH. Do let us know how the existing pump performs on a mains 3-phase supply if you are able to test it.

Interesting, remind me what part of the country are you? I think if we could get a naturally occurring pH of 6.6 we would be very happy and wouldn't bother about it! Was it the testing lab who advised the Juraperle? Will a 10" filter housing be enough for your flow rate (have just reviewed my correspondence with Wrekin Water and they advised a min size 8 in dia 35 in high vessel for 10 lpm)? I have looked into these but I think they are more suited to regular use by the professionals. For best accuracy you need to keep the electrodes in a buffer solution when not in use and recalibrate them periodically. Universal indicator drops https://www.water-for-health.co.uk/ph-test-colour-reagent.html have a shelf life of 3 years so I ought to get some more now. And they are above all reliable and cheap! The colour chart is a bit off though, IIRC pH 7.5 is a pleasing teal colour which is not shown on the test card at all. BTW when are you going to be back on site and able to test yr pump again?

Possibly. It is as ever a balance between capital cost, running cost and practicality. I decided to pay extra to increase the insulation on the tank itself from 50 to 75mm. The thermal store will be in a utility room so everything is inside the thermal envelope of the house anyway. The 22mm outlets will have heat traps, but for the 28mm primary connections it would serve no point anyway as there is flow all the time through the buffer section at the bottom of the tank. The tank will be at max temp for only a short time because we will use the heat again as soon as the Cosy cheap periods finish at 0700 and 1600. Octopus have just added an extra two hours from 2200 to 2400, which is welcome but has changed the planned usage pattern slightly e.g. we could charge it up for a third time and use it for background heat on the landings. The concept enables different flow temps for rads and UFH. In an ideal world I would add a further two-port valve so when the tank has got too cold for the rads we can use the residual heat in the UFH, but the design has been finalised with Vaillant now and there are no spare control outputs to do it.

All very true but the linear approximation is good enough for everyday calcs. The custom 270 litre tank I have got on order has a loss of 1.49 kWh per 24h which is small in comparison with the actual usage. This standing loss of about 60W is only 1% of the OP's proposed 5 kW HP output so can safely be ignored in the heating time calculation.

Don't think so. Quoted ratings of HPs are for thermal output not electrical input unless your Panasonic is different. Yes it will be a bit better in warm weather, but not by a factor of 3. But many ppl will reheat when it gets down to 40 as that is only slightly above body temp. So are not exercising it over the range 10 - 40C which accounts for 2/3 of the total stored heat input. Is O level physics. For comparison a 3kW immersion heater takes the best part of 3 hrs to heat the usual 210 l cyl from cold to 55C. Entirely consistent with the above.

5kWh is 4305 litre-degrees. So 5kW will heat a 300 litre cyl at 14.35 deg per hour. So about 3 hrs from stone cold. Reheat from tepid obviously quicker.

You may be right but even so it is a comparatively big and expensive extra vessel, according to the GAPS Water Treatment web site we would need the 13 x 54 inch size for 20 l/min. We have 5 micron and 1 micron filters upstream so the treated rainwater is in fact clearer than the mains water, which often throws deposits. The 1 micron one will soon need changing, we will replace the activated plant charcoal cartridge with one containing bone char which we have been told is better at reducing the iron content, another issue though no-one has any idea where it comes from as there is none in the system, it is all s/s, brass or plastic. Have just noticed this footnote on the GAPS site "*Note: If the inlet water contains iron or manganese it is recomended to use a backwashing unit instead to prevent media binding." Somewhere I also read that the backwash also serves to shake up the bed, wash out spent fines and expose fresh calcite surfaces to the incoming flow. The tank has a 4 in vertical inlet pipe going right to the bottom, the designers say this helps to aerate and stir the contents and prevent it becoming stagnant. So ATM we have been feeding Juraperle down this pipe, the thinking was the inflow would also spread the Juraperle about too. It seems to do that but still does not raise the pH by the expected amount so we continue with the bicarbonate which is pre-dissolved and fed down a small bore plastic pipe into the inlet.

It's historical, the previous owners had installed it, with many deficiencies, sorting it out was quite a project but we anyway needed to get new surface water drains put in after the garage was flooded. In hindsight we should probably have binned it, though (after the cost of consumables) the savings on water and sewerage charges are £100s a year. UVC is stainless steel so that is not the problem. We do need to treat the water anyway to avoid it dissolving copper from the cold pipework. Then the hot pipework is OK provided we do not exceed 55C. Not bothered about legionella. Perhaps. Have spoken to them in the past. The standard size we would need for a whole-house supply is 4ft 6ins high by ?10 ins diameter which is too big to go in the existing kiosk in the garage with the 2 filters and pump in it. Would also need auto-backwash on a timer, with a drain connection as well. Something more like this perhaps? https://www.ebay.co.uk/itm/374794124532. Only 3 litres/min flow rate though. Contact time with Juraperle is the issue, hence the height of the whole-house system vessel you need. Its advantage is that being calcium carbonate based its action is self-limiting to ?ph 8.5 so does not continue to dissolve indefinitely. Magnesium-based pH correction media like Corrosex are much faster but have an end pH of 10.0 (drinking water limits are 6.5 to 9.0) so not advisable on their own. Mixtures of 90/10 or 75/25 are recommended as a compromise but if you are away the magnesium component continues to dissolve making the water too alkaline. We have not found a foolproof way round all this at a reasonable installed price despite consulting several different equipment suppliers and a water quality testing specialist. And the water treatment firm who supplied all the kit for a local vineyard and winery(!) They proposed a bag filter containing Juraperle placed in the tank inlet pipe, but after a very long wait the one they then supplied was too big to fit.

Have been sold loose Juraperle in the past but not found a good way of dosing it. Cylinder sounds interesting, do you have a link? I have tried various things and recommend the liquid indicator drops, they give a much more positive pH indication than any strip. Have also used the 10-in-1 test kits from Simplex Health, they are quite sensitive tests for various metals and contaminants inc bacteria. But their pH strips are pretty useless.

Here you go @SteamyTea

I have a 5000 litre underground rainwater tank which collects almost everything that comes off 200 sq m of slate roof in a village in Devon, which amounts to over 200 cu m per year. It goes through multiple stages of filtration and then a UV steriliser. So it is fit to drink, though in fact we have mains water piped to the cold taps for drinking. Everything else gets fed from the rainwater - loos, washing machine, dishwasher, hot water system. The water is noticeably acid and the stainless steel spring in the UVC pressure regulating valve has in the past completely disintegrated. The acidity is because of the CO2 that gets dissolved from the atmosphere as the rain falls through it. I have used the free Aqion s/w to investigate this (www.aqion.de) and it gives the equilibrium pH as 5.61. Testing the as-collected water with pH strips is not reliable (because of the low conductivity), but I have found the Universal Indicator drops available from Amazon give a clear indication with a resolution of 0.5 pH. Typically it is pH 6.0 or less. I have had conflicting advice about this and currently dose it with 100g of sodium bicarbonate per 1000 litres. Even so it doesn't get much above pH 7.0 (though aquion predicts 8.28). Does anyone else see this as a problem or do anything to treat their harvested water?

More than happy to try and help. So no separate BMS as for my LiFePO4 batteries. Otherwise your system is enticingly similar to mine as we also have a remote tank, and yr Easy Solar inverter section is electrically identical to my Multiplus II GX 5000. So I have just run through the possible settings in VE Direct but there is nothing obvious I can suggest. Re-building the rainwater system that was previously installed at our house has been a long and difficult journey involving 8 ins of floodwater in the garage, a burnt out control box, a blocked pilot jet in a solenoid valve, two replacement pumps out of which I have built one working one, a new underground tank and learning quite a lot about filtration, corrosion and water chemistry into the bargain. Post the results here when you are able to get back to the site for further tests!