sharpener

Unless you are massively confident you will never get a prolonged power cut while you are on a winter holiday in the Canaries you should either use an antifreeze additive (glycol of some kind, they are not all the same) or fit AF valves. Inta are reputed to be good, others variable. Pipes inside the building/slab are less likely to freeze than the HX in the HP.

Well on the one hand the custom schematic for my system shows a strainer, but then all V schematics I have seen do. OTOH my installers are V approved ppl so I could reasonably assume they knew what to fit, and I preferred the idea of a big mag filter at waist height in the plant room to a smaller inline strainer outside nr ground level. Also as less likely to clog on account of the much larger surface area. And I reasonably assumed that an Adey HP filter would be suitable for commonly used HPs if not expressly approved by V themselves - though to me it does look on the coarse side. Lastly it seems to be a personal view this year's man has expressed. Since in the two years since installation there has been next to nothing in the strainer and the flow rate is still a high as when it was first installed I am inclined to the view that if it is not broke don't attempt to fix it, there is plenty of other house maintenance I can be doing weather permitting. FWIW I would still be interested to know how to test the concentration of the Adey inhibitor without buying their dedicated kit for £64.09, I am not impressed by just having had to pay £20 for their two spare O-rings which the man also suggested having to hand.

Had a service visit from Vaillant two weeks ago. He didn't find much in the filter (Adey Magnaclean HP) but didn't like the mesh size and said we ought to have inline strainers as well, as per Vaillant schematic. Last year's man didn't make any comment on this. I agreed it is a bit coarse (like a giant kettle fur collector but coarser) but said I didn't want to cut into pipe to add more fittings. He muttered about replacing blocked HX could cost >£1k and not covered by warranty. Previous oil boiler system had been cleaned with Fernox citric acid cleaner and their inhibitor used, always stayed nice and clean. HP installers used Adey inhibitor and biocide. IMO making sure the pH and inhibitor concentration are correct is best way of ensuring trouble-free operation, I have pH testing drops, man claims to have checked Adey inhibitor but I don't know what he used, what do other ppl do?

Just happened across this thread. Traditionally the kitchen cold supply was the only thing that came directly off the rising main to the tank in the loft, other outlets in the house would come from the (unwholesome) tank. When did this all change to requiring a balanced supply per G3? I suppose this is to ensure the same pressures at a kitchen mixer. If you don't have a mixer (like my separate pillar taps!) does it matter?

I was wrong, the Forge Steel is the one they stock https://www.screwfix.com/p/forge-steel-adjustable-basin-wrench-1-2-3-4-/410yc, looks about the same size. Now in my hand, it seems robust enough for occasional use. Agreed Monument are long lasting tools, I have a 30 yr old favourite pipe cutter - but now mostly use a pipeslice. No bc after I have reassembled it with a dab of Molyslip it will be easier to service in the future, as opposed to another new one which is bar tight.

OH is going to pick up the Faithfull equivalent from Screwfix for £9-99 on way to weekly shop. Have got cap off now but the head is so tight in the body I can't shift it with a 12" Bahco wrench without threatening to undo the union below (putting kitchen tap and dishwasher out of use), tap will have to come out so I can put body in a soft-jawed vice. No longer a 10 minute job (are they ever?), at least then I can put it back with the correct brass backnut and fibre washer.

Thanks. To elaborate am I trying to just get the central chrome bit out leaving the blue plastic ring behind? I have tried a thin knife blade, perhaps I just need to push harder but I would OH would like to avoid cosmetic damage. The action doesn't feel like a cartridge, more like an old-fashioned washer. In any event it goes round multiple turns. Unfortunately I can't easily change it. The plastic backnut split in two as stupidly I had not swapped it for a brass one so there is now a lash-up holding the tap down hence the broken packing round the base. The whole sink cupboard unit was pre-assembled and then fitted in its final position and a tiled splashback installed above. I don't think there is clearance to change the tap without reversing some of this.

... bought from B&Q maybe 10 years ago? Needs a lot of turning to turn off completely so I would like to try rewashering it. No visible grub screw. Can't prize any cap off the top to get at any fixings. Can't turn it on far enough to see any hex flat underneath to unscrew the headworks. Any ideas?

This may help https://johncantor.uk/pressure+flow/simulator.html

Nothing to do with radiators. The AGA consumes oil at a rate IIRC of 6 or 7 kW, and maybe half of this is lost through the cladding to heat the kitchen directly. A small amount of heat goes through the uninsulated ceiling to the master bedroom directly above, and the flue contributes a bit more as it goes in a duct up through the bedroom from which the air is extracted by the MVHR to keep the false wall free of the penetrating damp in the W-facing gable end. The diner half of the room has UFH of unknown spacing which gets the slate floor just perceptibly warm. All the rads are in the rest of the house.

You have still misunderstood. AFAICS with the VRC 700 you cannot have 3 different temps (though you can with the 720). See the pic from the manual I posted upthread. I have a barn conversion with thick stone uninsulated walls like yours. It is bigger than we need (except when we have guests) so we don't try and heat all of it all the time. The kitchen diner is heated by the AGA. The bedroom is heated first thing and last thing by the two rads, but the walls stay cold. The living room is heated by the two rads only from lunchtime until we go to bed. This is not conventional but works for us so I suggest you try it.

I am concerned about references to flow temperature in recent posts. Normally you do not control this directly, the flow temp for radiators is set by the controller according to the Outside Air Temp - colder outside means hotter water - according to a Heating Curve which is a whole new topic in itself. Start by reading Mick Wall's excellent tutorials here https://energy-stats.uk/vaillant-arotherm-basic-settings. Meantime do not tamper or change this aspect as other things need to be sorted first. [There are situations where you do not want the Heating Curve to apply e.g. towel rails but that is a specialist area.] No. Zones are separate geographical areas of the house. You may or may not have more than one (I suspect not). What you are describing is a Setback period. There is no distinction between night and setback periods. You can have up to 3 Daytime temp periods in 24 hours, everything else is Setback. This can be either a defined temp (in Setback mode) or heat pump OFF (frost protection only - Eco mode). As it says in the manual: 5.2.3 Setting time programmes You can use the Time programmes function to set the time periods. If you have not set any time periods, the controller uses the time periods set in the factory settings.

I was thinking of the S20/S21 contacts in the outdoor unit which I use to shut the HP off if the mains supply fails, as otherwise it would discharge the battery far too fast and there would be nothing left for lights and TV. But there are also the EVU terminals in the indoor VWZ AI interface box which are designed for the electricity utility to shut the HP down as a load shedding measure. Assuming this is in a suitable place you could use it with a 3rd-party time switch or even an ordinary light switch to give a simple on/off facility.

OK, here is the instruction manual for your VRC700 https://elearning.vaillant.com/vrc700/ci/en/documents/uk/infopool/Operating_instructions.pdf The timer mode on this controller is called AUTO. Setting up the mode and time schedule is explained on p13 et seq. Note that there are two sub-modes. The factory default setting is ECO. This will turn the HP completely OFF overnight which is what you say you want.Though I have some misgivings about that, the alternative is SETBACK where you have control over the overnight temp. I wonder if moving it to the landing would be an acceptable compromise, at least it would be in a circulation space not shut away. You can do this with a Vaillant but you can't connect into the ebus, you need to wire it directly into terminals in the outdoor unit which is not really a DIY job.

Good luck with that. V will argue that the VRC700 is compatible and they did not agree to upgrade the control box. To understand whether this is a relevant factor we need more detail of the HW "glitch". Of course. Better for @zoothorn to get to know the underlying physics, how his system works, its capabilities and limitations. But in the real world he may have to shell out folding money instead.