PeterW

Why..?? Use single skin Catnics straight off the shelf - they are all available and you can use either concretes or steel box lintels on the inside blockwork (or both for high load areas) so you don’t need an SEng to do it but you’re talking about £3-400 tops for all the calcs anyway as it’s all standard.

Only for hidden work and when I’m plugging stuff with wood plugs. Now use Reisser as I get them when they are on offer at TS or Howdens and are really good.

Yes if you run them too hard and there is any air in the system at all. Hence why having automatic air vents is ideal - if you look above the Willis there is a bottle vent which is highest point in the system.

Pumps are pumps - I have a pair of £35 DAB pumps running in my attic that have been there for 10 years, one of which is running 18 hours a day on a 72°C thermal store and hasn’t missed a beat. Downside..? It chews 45W and is getting slightly noisy but at 1p a day cost for the pump to date I’m not really worried...!! What would I replace it with ..? Wilo now, but that’s because they are pretty robust and low power and are not overly expensive. TBH, your new plumber reminds me of a number of IT professionals I’ve worked with, and the analogy that no-one ever got fired for buying IBM..!! He has no interest in selling you the best value item based on what it is being used for, and knows that he can “flog on fear of failure” to you with named brands. If that’s how you want to install stuff then your choice but I would suggest that your new plumbers bills will be significant for a gold plated solution which is pretty pointless. I also know that here are a lot of OEM products in this market, and I bet your plumber will not even know what they are .... but I bet he’s best mates with the Reps at Wolseley...

It’s a generic OEM part though - Grant supply them for their boilers under a different product code, and they list them as suitable for potable. Not surprised they told you bronze though as that’s the gold standard - they even spec aluminum in the US but they aren’t used in the UK due to all sorts of other risks !

This is on the potable supply as a hot water circulation pump. But agree about the lack of ferrous in the system.

So if you were to go with bronze as your choice (not that I agree with Wilo and they have been wrong before...!) then you can switch it if you want but I think you’re spending money you don’t need to. There is nothing ferrous in that plastic bodied pump to rust so it will never fail.

Consider one of the all in one units that only need the wall drilling for a pair of vents if it’s only one room.

So... go back 20 years and for DHW pumps the answer was “bronze pump guv...” and stainless was the realms of process engineering and aggressive fluids and were eye watering in price. Pumps had 60-90W ratings and they were big and noisy. Around 10 years ago, stainless started to appear in the market mainstream and it’s slowly had uptake but it is still expensive. Pumps got more efficient and electronic control started to appear more in the product set and pumps started to be seen with 40-50W ratings. Since then, engineering polymers and lightweight materials have become more prevalent, and pumps with eRP A* ratings have appeared with ratings of less 15W. This is simple product evolution. Engineering polymers cost significantly less than bronze as they can be finish moulded, and require limited machining unlike their bronze cousins. The costs have dropped dramatically and sub £100 pumps are commonplace. The downside is they are are an unknown in terms of lifecycle and slightly less durable than their cast predecessors. Don’t write a product off because your plumber has never seen it, or we are all destined to lead pipes and bathing in front the coal range !!

You’ll be burning fossil fuels but at the power station unless you’re on a renewables only tariff but even then you will influence the base load anyway. A cheap A2A will be sub £1k and can nearly be self installed if you get the pre-gassed ones. Otherwise you need an FGas ticket and vacuum pump etc to install it. Standard A2A at 7°C will run about CoP 3 so isn’t as efficient as gas based on price alone. First consideration for me would be double the size of the rads. Is this a generally cold room ..?

you haven’t got the wrong pump. You are scratching the motor body - that is always alloy. What is the impeller body at the back ..?

Who is your JCT contract administrator ..? Or have you downloaded the form and done it yourself...?? If its a homeowner JCT then it does state about VAT, if it’s a minor works then the assumption is ex-VAT but you can’t enter into one of those without a contract admin being appointed from memory.

@tanneja what is your spacing on the joists..?? 18mm will bounce as it is very thin. You could add 12mm ply across the whole floor and glue to the deck and screw it to the joists to give you a very rigid 30mm floor.

Yep that’s the one I’ve found and I think is used in some oil boilers that have hot stores hence why that vendor is selling them. Most likely an OEM pump to Grant or others and resold by them as a spare.

doesn’t need to be bronze, just needs to be not cast or steel as the oxygen in the drinking water can corrode steel. it’s a decent solution tbh and one that actually makes sense. Got any photos of the install under the sinks or bath as would be interested if it’s in 15/10 or 10/10 etc.

@Russdl That’s not a cast body - it’s a resin body by the looks of it so I would query the model number on the front as a resin body pump is suitable for potable water instead of a bronze body (and Wilo confirm this) And Hep2O can be used as a hot water return circuit. You have (incorrectly) read the guidance and don’t understand the BS/ EN definitions and I have had this confirmed by Wavin. For info the below is the definition they (Wavin) use for a hot water return circuit which you don’t meet on 2 of the 3 criteria so you have no issues.

Evening. Have a look at screw piles as they are easy to install and will do what you need.

Yep got it in one.

Read the Domestic Ventilation Guide especially section 5 which is the sign off section. Work back from that and you have a design. And you can always bugger around with it when it’s signed off - that’s the easy bit..!!

Have you set the water hardness and do you fill the salt container ..??

None by the sounds of it ... Far from it - you will just be heating a concrete slab and the ground underneath. With no insulation - 1950’s they didn’t use any - you will have basically a massive heat sink under the floor. What heat source are you using for this ..? Also, the tray systems work better with screed - you sound like you want to tile so if you have 40mm to play with and desperately want to use UFH, you need to go with one of the insulation panel systems which will allow direct tiling and allow for this at the door. That would probably limit you to 25mm insulation level max. You need to look at this sort of product. https://www.wundatrade.co.uk/shop/home/quick-shop/wundatherm-quick-shop/boards-quickshop/underfloor-heating-board-wundatherm-ultimate/

Common misunderstanding ..? Most likely as they are unusual. But for a single storey building with a pretty decent ground below there isn’t really a need for anything complex. Not quite sure why he thickens the width on the secondary footing as that’s not a detail you need for what is essentially a single skin brick wall. @gravelrash have you gone back and asked the question ..?

You will struggle to pump it up with water pressure on the system. Turn the water off, open a hot tap and then try again. You can strip the schraeder down using a valve key from a bike shop but beware that there may be pressure behind it so do it slowly.

Fully moulded premium product and very long lasting. I use BM for all the rainwater goods and it is streets ahead of the cheap FloPlast stuff that cracks easily.

so £2k install for all the system including tank and heat pump isn’t that excessive if you think this is a full tank install plus external unit and all pipework and electrics. There is probably a good day for internal and external for two people, and another day to sort your internal pipework and wiring etc. Commissioning is half a day, and you potentially need to link into a heating system too, so that’s day 4 complete. So at £2k, that’s £500 a day for two people to run a business, pay for tools, van, insurance and the tax and NI. Doesn’t sound expensive to me.