Jeremy Harris

It's not helped by both the lack of clarity as to what is actually going on within the controller, with zero feedback to owners as to the state of the thing, or the lack of information from Sunamp themselves about what they are doing to address the various issues that people are experiencing with these units.

@Mr Punter, it's as safe as any other, and has the newer green RCBOs fitted, which were replacements for the ones that used to regularly burn out in the earlier models. My two charge points just have DP Type A RCBO protection, as when I installed them that was all that the regulations required. The additional protection offered by a TT island, with DC capable RCD functionality, didn't become part of the regulations until this year, when the 18th Ed came into force. Before that, there was an IET guidance note that referred to having a DC-capable RCD protection device, with a TT island, but that was only mandated for installations that were partly paid for by an OLEV grant. Any installation that wasn't grant funded didn't have to comply with the IET guidance note.

It's correct according to the manual I have and the email I have from Sunamp themselves! My manual says this: and the email from Sunamp when I first ran into the charging problem says this: My controller was wrongly shipped with Option 1 set to ON, which meant it had to discharge down to 90% depleted before it would accept a charge. However, for the past few months it has been set to Option 1 OFF, so that it "only" has to discharge down to 50% depleted before it starts to charge. It definitely seems to be the case that it won't charge until it's about 50% discharged, as we can draw two showers (with some preheat) that use perhaps 4 kWh from the Sunamp, perhaps a bit less, and that's not enough to trigger it to then accept charge when the sun comes out.

The primary concerns seem to be both that a neutral fault may not be reliably detected and that the inherent DC component from the switched mode vehicle charger may DC block a Type A or Type AC RCD, so preventing it from tripping if there's a fault. The Rolec has a re-badged Chinese 40A RCBO of unknown parentage or specification as its protection device (others have tracked the OEM down to several on Alibaba). These seem to be Type A, not Type B. There have been quite a few recorded failures of the early RCBOs, with them overheating and burning out internally. I believe Rolec have now changed to a different supplier, and changed the colour of the lettering on the new RCBOs to green (from blue and black).

We have low profile down lights in our kitchen. They are barely any thicker than the plasterboard. I have a spare here in front of me and the maximum depth from the rear face of the front flange to the top of the spring that retains the light in place is a fraction under 20mm, so they project about 5mm behind a boarded and skimmed ceiling, perhaps 8mm behind a taped and filled ceiling.

Mine was supplied set to the "charge only when 90% discharged" state, but when I first installed it I noticed that it wasn't charging, contacted Sunamp and was told that it should be set to the "charge only when 50% discharged" setting. I changed the setting in the controller to this, which was supposed to be the default for our unit anyway. The ongoing problem of the Sunamp not accepting charge when it's available is with the unit set to the 50% setting. It "reliably" refuses to accept charge; it did this morning, we ran two showers and the contactor wasn't on afterwards, so I had to reset set it so that it can start accepting charge from excess PV generation. It doesn't always fail to accept charge, at a guess I'd say that about 75% of the time when I go to check and reset it it's already in charge acceptance mode, with the indicator light on (which I had to add as a mod, otherwise I'd not be able to tell). 25% of the time the Sunamp will be sitting them with the light off and the generation meter merrily flashing away, exporting power to the grid rather than using it to heat our hot water. Resetting the controller always, without fail, fixes this. The 25% of the time when the Sunamp refuses to charge is the problem, as charge power will shut off at some point during the day, and there isn't then another opportunity to charge until the boost period. I do not wish to have to use grid electricity we pay for to charge the Sunamp, when the damned thing has refused to accept free energy from our PV system. The really annoying thing is that the Sunamp PV did not behave like this at all, it just worked as expected every day.

The majority of it is 75mm OD, 63mm ID, although there is one brand that's 83mm OD, not sure it's that commonly used though, as there are half a dozen suppliers of the 75/63 stuff.

I suspect you'r right, although I doubt that will have much impact, as the RHI for a new build won't be massive. I believe that the reason for introducing the RHI wasn't related to new builds; it was aimed to incentivise improvements to existing housing stock. I'm not convinced it has had much in the way of a positive impact, either. I rather suspect it's been mainly been used to subsidise things like wood stoves and pellet burners, rather than ASHPs.

They will probably come out and have a look at the site a few weeks before they start, so with luck you can make sure everything is sorted out OK. The MBC part of our build was far and away the least hassle, it was really things that I didn't think for a moment would cause problems that ended up being the ones that bit me in the bum, hard, like the bloody borehole...

The Halcyan claims to work in a very different way to any other "water treatment device", and is definitely very different to the Combimate. The Combimate doesn't soften hard water, so there is still just as much calcium and magnesium in the water that's been treated, but it does stop precipitation of calcium carbonate on the inside of pipes, kettles etc. There is a running cost associated with the Combimate, as the phosphate beads need to be replenished every now and again. I don't know how often this needs to be done, or what the cost is, but perhaps @Mr Punter may be able give an idea as to running cost. I doubt it's very high, as the quantity of phosphate dissolved into the water only needs to be pretty small for it to work.

You'll probably laugh, but it seems that almost all charge points that have been installed over the past few years aren't in compliance with the regs! A condition of the OLEV grant is that they comply with an IET guidance note (now swept up into section 722 of BS7671) that requires all charge points to be installed as a TT island, with either a Type B RCD, or with a built-i means to detect earth leakage faults in the presence of a DC component greater than that which a Type A RCD will deal with (>6 ma DC). None I've seen comply. Mine is OK as this rule only applied to OLEV grant funded charge points until the 18th Ed came into force, and mine were installed under the 17th, 2nd Amendment.

Yes, that's different to us. I agreed to lay the sub-base and put in drains, ducts etc, MBC then blinded that. levelled and compacted everything and installed the slab. If they do the drains, ducts, sub-base etc then that removes the risk of them being in the wrong place, so it's a good move, IMHO, and takes even more risk out of things.

I have two charge points, one either end of the drive. Both are home made, and have about £15 worth of components in them. The most expensive item was the plug on the 32 A tethered one, which cost around £50. If I can design, build and test a charge point, using parts bought at retail prices, for well under £100, I find it hard to understand why they are being sold for £500 or so, plus the same again, or more, for installation. Someone, somewhere, is making a great deal of money from these things.

Yes he has, I believe, but I'll check when I seem him tomorrow. The headline prices for charge points seem to be a fair way off the true price, but even so, £200 after the grant = £800 in reality, for a unit that costs around £400 trade price (probably a fair bit less than this, as they retail at under £500), plus around £50 of materials to install, and which takes 4 hours labour? That's still just under £90/hour for labour.

Our rafter span is about 5.5m, but because they are ridge hung they need to be quite deep. The basic rafter is a 302mm deep I beam, with an additional 100mm deep spaced stud nailplated to the underside to give 402mm overall.

I think they will, and I also think this will come home to bite them when they roll the electrically charged units out to the mass market (and I should be clear, this failure to charge only applies to the electrically charged models, not those charged by hot water). It may well be that they don't see the electrically charged models as being their biggest sellers, so aren't bothered if they don't work as people expect. As there's been no communication from them (they do have a presence here, Andrew Bissell is a member) we simply have no idea what's happening to address this.

Excellent point. I established two fixed datum points, one was a handy OS spot height nail in the lane next to our drive entrance, the other was a fixed T post in the North East corner, outside any excavations. These proved invaluable when doing the cross checks to ensure that the base for the slab was in the right place and that the ducts, pipes etc were all coming up in exactly the right places. Our ground works chap though I was mad in insisting on sub-20mm accuracy, but it turned out that this was only just good enough; we ended up with a soil pipe that was right up against the edge of the frame and another 10mm of clearance would have saved me half a day of frigging around to get things to line up. Well worth hiring a Total Station, if you don't have access to one, too. Our ground works chap had one, and without it cross checking the exact positions of things would have been a pain.

i'm inclined to agree, they don't care because self-builders are not a big enough market to worry about. I can't help feeling that the inability to reliably use PV as an energy source for charging, something that was the focus of their first ever product to market, and which established their name, may well come back to bite them, once they start selling units in volume, perhaps to the big house builders.

I was thinking of you when I typed that!

Yes, his quote is for a Rolec, which is really at the bargain basement end of charge points.

Good point about I joists, @Russell griffiths. We have 400mm modified I joist rafters, and realistically blown insulation was the only sensible way to insulate the roof. We have 400mm of cellulose, with rooms in the roof, and have found that the U value and decrement delay is such that there is no rise in upstairs room temperature at all on very hot days in summer (and one face of our roof is just a bit West of South). An unexpected benefit of the fairly heavy cellulose is that it's an extremely good acoustic insulator, so we can't hear rain on the roof, or any sound from outside. It wasn't something I'd thought about before, but it's very noticeable when living in the house just how quiet it is inside, spookily so at times.

Spot on, it is indeed madness. I personally feel pretty bad about this, as we had one of the first Sunamp PV units and that worked so well I extolled it's virtues, both here and on Ebuild. Had I known what was to come I'd have been more circumspect. The main worry is not knowing whether it has decided it's able to accept a charge or not. This seems to be an ill-defined state, as sometimes when I go in to reset the controller it is already in the charge acceptance state, sometimes it isn't (however, Sunamp chose not to provide any indication of this, as it was such an essential feature I added a neon light to provide this indication).

Yikes! I think that is probably a Buildhub record price (might be wrong, there may be one member here that has come close to that). A reasonable average price for a self-build is around £1,500/m², some have managed to come in under £1,000/m², some may have ended up at around £2,000/m² Ours ended up at around £1,380, with a fair bit of work from me (my labour saved perhaps £200/m²).

Thanks, I don't for one moment doubt that you're happy with the unit. it's the fact that it is not a water softener that bugs me, as they claim that it does soften water when they have said here that it doesn't.

There's a potential work around for the controller failings, but I've been reluctant to implement it, as I would like Sunamp to come up with a fix first. The work around is to add a time switch in the 3 A supply cable to the Sunamp controller, so that the unit gets reset. Initially I thought it would be OK to do this reset procedure just once a day, to ensure that we have hot water in the morning for showers, but I'm wondering (after we nearly ran out of hot water again a couple of days ago) whether it really needs resetting just before any likely charge period. At the moment, I reset our unit at about 08:00 each morning, after we've had morning showers. This is to ensure that it's able to accept a charge by the time the PV system starts generating. The idea is that the unit should charge from PV during the day, if there's enough excess generated. To cope with days when there is little or no excess PV generation, I have a boost time switch, that bypasses the PV diverter unit and supplies power to the unit during the off- peak period (the boost time switch turns on at 03:30 and off again at 06:00). In theory this should ensure that we always have enough hot water available for a couple of showers in the morning. However, this system can fail if the Sunamp gets fully charged from excess PV generation during the day, and then a bath is drawn off in the evening. What seems to have happened is that one bath is not enough to trigger the controller to put the Sunamp into charge mode, so it then doesn't boost during the off-peak period. If the first shower in the morning is longer than normal, then there is barely enough hot water left for the second shower (mine, usually). I'm beginning to think that it needs to be reset twice a day to be sure that there is always hot water available. This is really barking mad, as the old Sunamp PV was around half the storage capacity yet never failed to provide hot water and always charged up whenever power was available.