marshian

I'd replace the olive and use less PTFE tape but I'm not a plumber or heating engineer like @Nickfromwales Watch this and you'll see exactly what over tightening an olive does and why it causes leaks to get worse (PS his presentation style is awful and irritating but from a content perspective it's worth a watch) I also prefer to use LSX rather than PTFE tape but either are pretty fullproof solutions to leaks from compression joints without excessive tightening https://www.screwfix.com/p/fernox-ls-x-leak-sealer-50ml/23614 No idea yet on how to do an embedded link perhaps @Nickfromwales will share that secret

I already asked that 🙂

Oh I had the sane sort of leak from a cold water storage tank in the loft - didn’t know it was happening untill I saw the ply boards it sat on were bowing with the weight (soggy ply did well to hold it) I will state that technically it was self inflicted - house in a hard water area and I fitted a water softner - for two years I kept finding the odd leak that had never been an issue before (softened water takes back limescale from where it finds it - so some old joints that had clearly leaked in the past and had been sealed with limescale were suddenly free to leak again

Excellent spot - provided the boiler is on ground floor could you shut all the unaffected rads and drain down the problem one by opening the rad bleed as they will still need to drain to below the level of the lockshield?

How old is the house? mine was built in early 1980’s they didn’t put any drain valves in at all you can get round this by shutting one rad (both ends - noting the position of the lock shield valve, turns to close or or turns to fully open) once you’ve released the pressure in the system pick a rad pref near a door and on a hard surface like tiles or lino release the system pressure first using the bleed screw and a jug to collect the water once that’s done shut both valves - crack the union to the rad tail - then drain the rad with suitable tray or tupperware container from the cracked union (plenty of old towels to catch what misses the container when rad is empty you can normally remove the rad fit a new tail to one of the valves with a hose attached and then drain the system via the hose please ask if you want more explanation or pictures and I’ll try to pull a few bits out of my spares pile to illustrate what I’m describing

For me the first thing to establish is what is actually leaking is it A. the lockshield valve gland B. the compression fitting to the 15mm feed/return pipe C. The compression fitting to the rad tail D. The rad tail Once identified you can consider if whole system needs to be drained or if a partial draindown can be carried out For instance if the rad is upstairs then you only need to drain down upstairs to a level where a repair/replacement can be achieved without issue If downstairs then you can shut all of the TRV's and Lock shields upstairs to leave more of the water in the system (downside is it's faff and you need to carefully note down the lockshield positions so you can reset the circuit balance to as it was) I've "hot swapped" a lockshield valve before* but on a tiled floor not carpeted - not sure I'm brave enough to do that on a unvented system (I'm a vented system so the pressure is limited by the head of water in the loft.

Not sure which post is correct but 4 bed family of 2 using 50 to 60 kWh of Electricity a week (winter higher than summer) (Yearly average is 8.5 kWh a day) Gas CH & HW - Electric Oven but Gas Hob (No EV) No battery or PV

Just one more point - people and their activities are the problem with humidity levels in houses - especially when you improve the leaky nature of older houses where they were never designed to be sealed up. Google says on average A person exhales 400g of water a day that is released into the air Boiling a kettle puts 10g of water on each occasion released into the air Cooking on a hob for 10 mins can generate 100g of water released into the air Bathing or showering can release 1.7 kgs into the air Total water vapour released by a single person doing all of the above daily can be as much as 2.5 kgs of water. If it isn't removed it's going to cause damp or mould The primary exit routes for PIV forced air into my house are Bathrooms (Fans are on timers but only run for 30 mins and aren't ones that close the pathway) Kitchens, Keyholes (I know it sounds mad but you can feel air coming thro them) Letterbox and 30 year old rubber seals on windows and some of the doors - all of that is enough to provide exit routes for ventilation out of the house

It can if you set it up badly ie too fast for the what is required. One I have fitted has 6 speeds Lowest speed is 10 l/s - Fastest speed is 60 l/s My house volume is 290,700 Litres This means On the lowest speed it's taking 8 hours to "Theoretically" do a complete air change in the house On the highest speed it's taking 1.4 hours to "Theoretically" do a complete air change in the house I have humidity monitoring in several rooms in the house and basically experimented with speed settings whilst looking at the humidity data trends to determine the speed that worked best (basically speed 3 or 4 during heating season) I do run the PIV unit differently in "Heating seasons" to "Non Heating seasons" Autumn, Winter and Spring - Schedule is as follows 00:00 to 06:30 On 06:30 to 08:30 Off 08:30 to 17:00 On 17:00 to 00:00 Off Fundamentally it's on when we are asleep or not in the house Summer (it's run on speed 6) 00:00 to 06:30 On 06:30 to 08:30 On 08:30 to 17:00 On 17:00 to 00:00 On Reason for the difference in schedules is when loft temps go above 27 deg it shuts down so it's probably off for 40% of the day and in order to hit a reasonable air changes I increase the speed It has an inbuilt direct electric heater but I don't use it - never found the need to use it (I accidentally used it for three days when on holiday and we had a sharp cold snap and I didn't like the kWh used) As I said my house isn't Built Tight it's leaky (Not as leaky as it was but no where near the std of most builds on here) and I'd rather control the ventilation in the "out direction" than "uncontrolled in" I think I covered the reason for fitting in another thread but in a nutshell I made a significant improvement to my house insulation (Suspended wooden ground floor that had a well ventilated crawl space under it) I insulated under the floors with 75mm PIR between the 100mm floor joists all 56 m2 of it I already had humidity monitoring and the readings spiked as we had lost some uncontrolled ventilation from below the floor - Condensation on the inside of double glazed windows and doors on cold mornings was typical - we hadn't seen that since fitting SUDG to replace single glazed wooden windows back in mid 90's. PIV fitted and all the humidity levels dropped back to same or lower than previous and only place we ever see condensation on the inside of windows is when cooking in the kitchen without either extractor fan on above the hob or opening a window slightly Slightly longer reply than intended - sorry

Heat loss predicted 6.7 kWh proposed 7kW Valiant Aerotherm £6300 after BUS grant But there are a lot of “extras” I didn’t select like new HW tank It works better as a first pass but I’m not going to proceed with £250 fee for a proper assessment

Old HG quote system yes - new one no (not yet) it gave me an install cost of £6500 after BUS grant I fully accepted it was a mile out for multiple reasons it doesn’t know 1. what improvements have been done to the in terms of insulation 2. All the rads are now twice the size of originals (which were fed by a non condensing boiler from the 80’s) 3. I’m already running low temp heating (25-35 flow) 4. the house has never had an EPC so it can’t look to that so I didn’t mind the fact it was a mile out

Unless there is a open window the air will take all paths open to it it doesn't need to be much of a leak to cause a dramatic reduction in humidity and as a result condensation

I disagree You don't need trickle vents if you have leaky property - air finds it's own path - past windows - past ceiling roses - anywhere that's not sealed Build Hub "Built it tight - ventilate it right" 100% agree but I'll put £20 on the fact that the OP has a leaky property from an air tightness perspective and a PIV unit will resolve his condensation issues Experience is what you get when you don't want it

Just fit a Positive Input Ventilation (PIV) unit - that’ll solve 99% of your condensation issues

Down side (from a quick look at the specs) whilst it does modulate down to 3.5 kW the min flow temp for CH is 40 Deg (max is 90 Deg) With UFH throughout seems a shame to have to blend the temp down rather than get a boiler that can run at temps low enough for UFH but I'm pretty sure that'll just me me that's concerned about that

I don't agree I've got T22 rads - they replaced T11 rads in a 1980's house - they are the same size as original - just thicker - They are not silly sizes. My WC flow temp starts at 25 deg C and ends at 35 Deg C at -2.5 OAT It's perfectly possible to run UFH flow temps thro rads and still keep a house at temperature

And he has a multitude of suggestions He can pick the bones out of the thread

Couple of times I had to email Octopus because my bill has fallen into limbo land - it ends up in some weird stasis situation and they don't know. Each time it takes about a week. I wouldn't mind betting that's the reason you've only got a bill now

Because at that point he will be missing (hopefully) two x 30 min shower times and rattling around in the house without the need for "unlimited" HW........ Plus lets not forget - not having a tank rules out any PV assist to water heating during summer months if that is later added....... Combis are fine for small houses, apartments and flats - madness IMO in a house with 3 bathrooms and a requirement for multiple showers at the same time

No entrapment there at all - Not Guilty is my plea I don't think there will be 1. A ban on sale of gas boilers or 2. Gas will run out But I do think cost benefits to convert from gas and oil to ASHP will be incentivised by methods other than a grant and price of the fuel is one

I refer the honourable gentleman to my reply to @JohnMo I specifically did not say anything about a ban on gas or it running out The economics of ASHP conversion are currently being bolstered by a £7500 BUS grant (Ignoring the grant harvesting impact) it wouldn't take a lot of movement in gas price or more importantly the standing charge to further drive the move to ASHP's - especially when the BUS grant scheme ends and equipment cost falls

I feel you need to read the first post again My point which I will make again is that if the space is not made for a tank due to a hoofing great combi and no tank - it's going to be much harder at a later date to fit in a tank into a house that wasn't designed to have one. Not disagreeing with you - more than one way to skin the proverbial - but it's a forum which shares different opinions - the discussion of pros and cons - will hopefully lead the OP to a decision that he has to live with preferably happily!! As far as fossil fuels go (and I have recently replaced a gas boiler with a gas boiler) it might not be a ban on fossil fuel boilers it could as easily be the increased cost of fossil fuels as a result of ASHP becoming the norm - the costs of the gas grid would then have to be covered by the remaining gas customers............... This could result in the "economics" of gas driving further conversions to ASHP....... JM2pW

OP ruled out ASHP on his new build - downside of fitting a bloody great big combi is when he does “have to go” to an ASHP he’s then got to find space for tank which was never allowed for in the build makes no sense to me at all to go down a combi route

Wasn't the point being made........................

80 - 20 rule for me If I can get 80% of the benefit for 20% effort I'm comfortable with the compromise I'm not going to put 80% of my effort in to getting the 20% extra - big wins for min effort every time for me I could have fitted 100mm of PIR under my suspended wood floors v 75mm the cost would have been 40% more 75mm PIR U value 0.33 W/m2K 100 mm PIR U Value 0.23 W/m2K When I considered my actual floor losses once I was over 50mm the bang for buck was done. Payback on 75mm was 4 years (Russia helped me out - I was projecting 8 years based on energy cost increases)