Jeremy Harris

Not sure there's any useful reason for running an anti-legionella cycle on a closed hot water system, as there is no opportunity for a primarily droplet/airborne pathogen like legionella to get into the pipework or tank, plus the residual disinfection from water treatment should mean that the water entering the house is bug free (that's a statutory requirement in the water quality standard).

Ours had single check valves on both inlets (accessed from the rear) that looked like the same design of cone-type valve as used in an inline check valve (they were visible by looking down the inlet holes). I didn't take it apart and check, but the guff that came with the mixer also mentioned another check valve built in to the thermostatic cartridge (accessed from the front). My assumption (might be flawed) was that having two check valves in series met the requirement for a double check valve. I wasn't really too bothered to check further, though, as the shower head can't physically reach anything like a WC.

It's not. Having seen how it works, I'm not convinced that it will be approved any time soon, either. Their current G100 approval only applies to their export limiting device, I believe.

It doesn't get around this problem. The Gateway 2 just works like all the other battery systems that have a backup option. It's one-way, in that the PV inverter still will not turn on unless there is grid power available. Many battery storage systems offer a power cut backup supply option, either via a dedicated backed up output from the inverter/charger, or via a changeover switch and an inverter that has an islanding mode for output. I'm not aware of any (other than dedicated off-grid systems) that will allow the inverter to start up without being able to sense the grid in order to frequency sync, do the required safety tests, etc. It's possible to build a system that uses an off-grid type islanding inverter/charger, with an anti export protection device on the grid power changeover, but it's a bit of a faff to set up, plus there are not many approved anti-export devices available yet. You can use a DC coupled system to get around this limitation. That works by using the DC from the PV system to charge the battery pack, with the batteries then used to run an inverter. The inverter needs to be a model that can switch between islanding and non-islanding mode on the fly, plus there needs to be a grid power changeover switch, plus an export limiting device. The inverter also probably needs to be sized to be able to deliver the full output from the PV system, if it's still going to export to the grid via the grid power export limiting device. Not impossible to do, but probably not worth the hassle. Most power cuts are of a short duration, so just having the ability to pull backup power from the battery pack is probably enough for the majority of people.

An off-grid inverter can do this, but cannot then be connected to the grid directly. It is possible to build a battery system that has two inverters, with no AC connection between them. There are a few ways to do this, but none of the commonly available domestic battery storage systems currently have such a capability.

Yes, the inverter needs not only to have grid power available to start up, but that supply has to pass the inverter power-on test parameters. Most inverters check at least the loop impedance and grid frequency during startup, and will only turn on when both are within limits. Some inverters display the measured parameters during startup (ours does) so that any out of tolerance measurement can be seen.

Cannot be an off grid system, as it's AC coupled and grid tied. The inverter has an auxiliary backup output, but that is asynchronous. The inverter still needs to be grid tied to start up.

Is the power back on now? If not, then the PV will not start to generate, as it must grid lock before the inverter can turn on.

I did something similar. I ran extra circuits, mainly outside runs of SWA, terminated in waterproof terminal boxes. The installation was inspected, tested and signed off, and when I came to add things like our borehole pump, water treatment system, outside power points and car charge point I didn't need to get anything "Part P'd". I still have two spare circuits like this, one of which is earmarked for a battery system.

Probably worth checking the spec of the shower mixer, as some have built-in check valves (ours did). The check valve is in the thermostatic cartridge on ours, with additional integral check valves on the inlet ports. Also, I believe the regs only require this if there is a risk that the shower head can contact contaminated water, so a flexible shower head being able to drop into a bath or shower tray. There isn't a requirement (as far as I'm aware) for a check valve with a fixed shower head (unless the regs have changed recently). The standard (but unsatisfactory) way that some manufacturers get around the need to fit a check valve for a flexible shower hose, is to include a ring on the shower rail through which the hose is fed, so it cannot drop down into the tray/bath. Given that many people probably unthread the hose from this ring, I've never been convinced it was a sensible way to get out of fitting a pretty simple check valve.

My 'phone is pretty abysmal at reading my fingerprint, too. Never yet had it work first time, and probably half the time it defaults to having to enter a PIN to unlock it. When we tried fingerprint readers on doors at work they had the same sort of problems, so we switched to retinal scanners, that seemed to be a great deal more reliable.

The only solutions I can think of that may work would be to forget about making a brick, block or concrete retaining wall, and look at a porous option, like gabions or perhaps timber crib. The problem with these options is that both tend to take up a fair bit of space. There's no solution that can avoid the problem of a retaining wall slip plane being lubricated by water, other than drainage to remove the water before it gets down to that level. Our neighbour wasn't easy to deal with, but we managed to negotiate with him, on the basis that we covered all the costs, including the full reinstatement of the strip of his land we'd disturbed and building the side of the boundary wall above the retaining wall that faced his house to his (expensive. . . ) spec (it's rendered on our side, but stone faced on his side).

Our retaining wall also has its rear face dead on our neighbours boundary. Because it was absolutely essential that the rear face of the wall have drainage, I negotiated with the neighbour to excavate a couple of feet of their garden, carefully removing some of their shrubs and plants, and then reinstating and replanting it all afterwards. Any retaining wall that has water behind it is very likely to fail, if not from the effect of hydraulic pressure, then from lubrication of the slip plane under the wall. The water is going to find a way out, and what you don't want is water down at the wall foundation level, as that's likely to cause premature failure.

You have two problems, really. The first is getting the wall built in wet conditions, the second is that the combination of hydraulic pressure and lubrication of the slip plane under the wall foundations could cause the wall to fail. The normal solution for both is to install a land drain in a gravel bed at the retained side of the wall, as @PeterW suggests above. We had to do this behind our big retaining wall, as a requirement stipulated by the SE that designed it. How high is the wall?

Most here started out not knowing much. This place is a bit like a self-build university, where we all learn from each other.

Probably best to try and find a Part P electrician who would be OK with you doing all the grunt work. There needs to be a degree of personal trust by whoever agrees to work like this, as the regs cover everything, including where cables are run, how they are secured (including the need for fire resistant cable clips or other securing methods now), how they are mechanically protected where they need to be, de-rating when cables are run in insulation or locations other than clipped direct, etc, plus the person signing off the installation will be signing to say that all the cable runs etc (some of which may be hidden from later inspection) are compliant, so they'd be taking your word that the runs are all OK. Alternatively, you can opt to do the whole installation and then get building control to do the inspection and test. The only snag I found when I tried to do this was that our local building control didn't have anyone who was competent to undertake third party inspection and test. They are supposed to, but they told me that none of the Part P accreditation bodies were happy with granting this type of accreditation (makes sense, they very much want to protect their closed shop cartel business).

All of our internal soil pipe is push fit. It's more tolerant of a little bit of movement and vibration than solvent weld.

I've merged the two threads on the same topic

Worth checking, as it's a fairly common requirement. The local policy here states that vehicles must be capable of entering and leaving in forward gear, and a planning condition requiring a turning space is also normally required (although they will accept a turntable). This is the wording in our planning consent, and I think it's a standard condition they apply:

We got caught out by Santander reneging on the agreed mortgage we had with them. We set everything up, signed all the paperwork, paid the fees etc, about 4 or 5 months before we needed the money. We paid for the plot and ground works out of savings, planning to draw down from the mortgage as soon as we placed the contract for the foundations and frame. When I went to drawn down the mortgage, Santander told me that they had changed their lending policy and that the funds were no longer available. Apart from causing a bit of a panic to quickly arrange a new mortgage with another lender, Santander also refused to refund the fees. Took a long battle to eventually get the money back.

I just read an apt description of fuel prices at the pumps, and the reason they always seem to go up within hours of the oil price increasing, but take weeks to go down. It's because the pump price contains hydrogen, so being lighter than air it floats up, but needs to be physically hauled down . . .

I looked at fitting some Dutch through the wall individual room MVHR units. They seemed pretty impressive, very quiet and with decent performance. The snag I ran into was that they would have ended up being extremely expensive, as to meet building regs I would have had to fit loads of them, even though the manufacturer made it clear that we'd only need two, or possibly three, for our size of house. This probably isn't an issue when retrofitting MVHR to an existing house, though.

There's a thread here discussing it in more detail:

Sometimes they can, sometimes they seem to die without making much smell. We had one that died in the loft of our old house, right next to where some cables led down to an outlet in the living room, and the smell was appalling, forced me to try and find where it was coming from (which took over a day, as it was under the loft insulation). I've also had mice die and just seem to dehydrate, with no noticeable smell. I think it probably depends on how quickly the dead body dries out, so may be very temperature and humidity dependent. I can say that when you do get a smelly one the smell can be very persistent.

You might get away with it, after all, a soil stack usually has a swept 92.5° bend at the base. If you can fit a swept bend in at the bottom of the top vertical bit, then the second 92.5° bend turning that back down to the vertical isn't a problem. Blockages occur when the velocity slows right down, and although bends do slow things a lot, the vertical bit will mean that the velocity at the bend will be pretty high to start with. I've only ever seen bends cause a serious flow problem when they are near-horizontal, not when they are vertical, TBH.