Hastings

@sharpener Just to be certain, I need to swap brown-black on the 3-phase output, not the input terminal?

Controller manual also says to contact the manufacturer MAC3 if using with a generator and/or UPS.

No The installation manual for the controller says: "Connect the output cable (ground, triple-phase, screen) to the 3-phase pump using triangle configuration 230Vac." I have been studying online resources on "triangle configuration 230Vac" but am unable to interpret it.

Ah, you are correct, thank you. My pump is a speed controlled version - has a separate box/inverter with it to control speed and set the switching pressure - the graph I posted above must be for the pump alone. It has been disconnected for shipping back to the supplier (the pump and controller units in separate boxes) and then back to me. Maybe they wired it differently for their tests. The wiring I have used is according to a colour diagram label on the pump body but the electrician gave me a different mapping over the phone (he didn't sound too sure and so I chose the former). I don't recall if I checked this with Tom at 3PTechnik. Perhaps the one on the pump is for Italy 3-phase and different to UK 3-phase . Wiring for my pump (Output:grey, brown, black green/yellow. Input 240V) within the controller:

Mine is the 120 of the 3 available pump versions shown.

I had forgotten that the pump does indeed have 4 wires which are for 3-phase connection. Is it possible that I wired it up wrong? I assume that if I had wired it wrongly then it would not run at all or run in reverse or something else other than pumping poorly. Correct, I have been reporting only static pressure against a closed stop tap, not dynamic pressure. I am also baffled as to why adding the pressure vessel (and a little more piping) resulted in a better static pressure result. I noticed, only now, from the manufacturer's data sheet power curve that power consumption is a pretty constant 1.2kW at all flow rates. That is a surprise (and a disappointment) but at least it indicates that the pump is behaving normally in that regard and not necessarily 'struggling' as I had assumed. I bought the pump from 3PTechnik and have had much correspondence with Tom and his colleague who carried out the testing.

Can anyone please confirm from the label that my pump is indeed the 3-phase version of the pump (and not the single phase version)? I am guessing that the "Vc 450" means it is?

@JohnMo I am sorry but I don't understand your point.

Tested the pump and controller on a neighbour's house single-phase mains supply yesterday and there was only a very a small improvement in maximum static pressure achievable: 2.0 bar, instead of 1.8 bar I get at my house. I was not able to measure the power drawn but it appeared to get up to pressure faster and without reaching full rpm. What was interesting was that when I first tried the test I did not include the pressure vessel in the output and the pump could only achieve 1.2 bar.

I ruled out a header tank in the loft at a very early stage of my house build due to being told that new toilets and washing machines might not function without at least 1 bar (10m head) of pressure. Is that not correct?

Yes, 1.3m annual, Met Office data. Low lying islands are quite a bit dryer than mainland A&Bute. Rainwater will be used in the kitchen, basins, shower. Just trying to point out in this discussion that any roof design for water collection can only, for the vast majority of UK housing, be a partial solution and therefore unlikely to be cost effective. Unless the law is updated to allow householders to use much less if they want.

Annual average is 1,300mm, which (discounted 20% for losses) works out at about 480 L/day. Not enough rainfall for a household of more than 2 people when rainwater collection is the entire water supply. Normally 200L/day/person is required for a new build water supply in Argyll & Bute.

Pretty sure that rainfall is not sufficient in UK to supply toilet flushing needs in most houses occupied by more than perhaps one person, even if you have sufficient storage to catch every drop. My house with adjoining garage in Argyll & Bute has a big 160sqm roof and receives twice the annual rainfall than eg. Oxford yet is considered by the local authority to be insufficient for more than 2 people.

I believe it is acceptable in Scotland building regs to plumb this to a drain stack rather than directly to outside but I may be wrong. The main issue though is how to prevent gases from the soil pipe entering the house - normally a u-bend trap is fitted but this will dry out and fail without regular topping up - a dry trap, fitted vertically, is better.

We regularly get some salt from the sea sometimes but it's probably not enough to raise the pH of the rainwater in our 10,000L collection tank. Proximity to urban centers, where more SO2 is emitted, is the main factor. https://naei.beis.gov.uk/data/map-uk-das?pollutant_id=8 Acid gas and aerosol monitoring sites: https://uk-air.defra.gov.uk/interactive-map?network=aganet

Southern inner Hebrides. Local contractor suggested and supplied Juraperle pH correction, remotely. Surely only a rough and easy solution, given the variable flow rate expected. I am back on sit 16th July.

Our slate roof collected rainwater measures 6.6 pH by a council approved lab, which is just inside the permitted lower limit 6.5. We have been prescribed Juraperle granules to put in a standard clear 10" long filter housing, a few handfuls to start with, to add to as required to get up to at least neutral pH 7.2. I don't have any pH testing means. Did you try the electronic pen type pH meter? Quite expensive but maybe a good investment if it means preventing plumbing parts like springs inside pressure reducers being damaged.

The batteries are managed directly by the 48V 5kVA Victron EasySolar (Multiplus and Solar charger in one unit). When the pump is pulling full 1200W and battery bank in good SoC the voltage drops from about 52V to 50V or so.

@sharpener Wow. I am grateful, somewhat lost for words and humbled by the expertise, time and effort you have put in to this. Thank you. I had already been thinking about the logistics of taking the equipment to a friend or neighbour's house to test. Now it looks very much like a worthwhile undertaking. Yesterday I tried running the generator into the system while pumping water but it made no difference. The generator is only 1kW, its function being to charge the battery bank when solar is insufficient, so I cannot run the pump off it directly. The SoC of the battery bank doesn't vary the behaviour of the pump at all other than stopping it entirely when the DC voltage drops below the Victron shutdown limit. So I think you have very likely found the answer but frustratingly I can't do the phone-a-friend and house mains test as I've just left site for the next 2 weeks. No, I have no special arrangements with the supplier to allow for returning the equipment but I'm a dab hand at eBay, learnt from disposing of outdated photography equipment during a career as a cinematographer.

Me too. The green gypsum board throughout, then tanked just the shower area up to head height, skimmed and painted the rest. Walls are all timber-frame, therefore tanking is essential I would have thought, at the very least around all corners.

@SteamyTea This I think is a motor based device driving a small fan and compressor? So also an inductive load? I guess too small a load to have significance re. the issue under discussion.

I have a cheap single phase 750W dirty water pond pump. It might be a useful test of the power supply to see what pressure I can achieve with that. I'll need to buy a pressure gauge.

I may have mis-remembered this. I am not very technically minded and pretty bad at storing numbers in my head during phone calls - it was a few weeks ago.

And so an induction kitchen hob (not that I have one but I have been seriously considering it) is also not a resistive load but inductive as the name suggests?

The supplier said I couldn't extend the connecting cable between motor and controller much due to an issue with "harmonics". The pump controller manual "recommends the addition of the Long Connection Adapter for cable lengths over 20m, obligatory for lengths over 100m, to reduce overvoltages created by using long cables between pump and controller".