Please criticize my plan

SJB060685 said:

Thanks fixitflav. Yes I have a basic understanding of the laws of thermodynamics but I feel I should know more lol

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I didn't mean to imply there's anything wrong with studying thermodynamics, it's a very interesting (and very large) field. Just that only the most basic concepts are relevant to heating systems.

The new mantra in the design world which I think you should bear in mind, I know because I am involved everyday in this dynamic commercial world...plumbing heating hvac etc
COMPLICATED is EASY...SIMPLE is HARD....the trick is to design OUT the problems in your system
in my opinion ... centralheatking

fixitflav said:

I didn't mean to imply there's anything wrong with studying thermodynamics, it's a very interesting (and very large) field. Just that only the most basic concepts are relevant to heating systems.

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I didn't take it the wrong way my friend don't worry. I know like you say only the basics is relevant but I'm always looking to further my knowledge 🙂

king of pipes said:

I have been following this one with interest as Norwich is in my area you seem to have your heart set on the type of system to you would like installed siricosm ? . Brambles has given some good sound detailed advice in his replies and alot for you to consider I personally would be guiding you to look at Joule range of products I speak from experience here they are up there with the best manufacturing buffer tanks , unvented cylinders, thermal stores and everything you will require control wise. If you go with traditional cast iron radiators then your heating supply pipework will without a doubt needed replacing as you simply will not achieve the flow rate to heat them I will continue to monitor your posts from experience you will definitely need a water softener in the Norwich area and it's even worse as you get out of the city and in the surrounding countryside. Regards kop

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I am still open to suggestions for the DHW side, I am not sure if I should go with a tank that has a large coil like the OEG I had before, or an external exchanger like in the plan above. Brambles suggested a tank-in-tank, which for a 300l store would probably give a bit better performance, but probably also cost more. I am leaning towards the OEG, as it is the simplest, I had it before so I know what to expect, and it is probably the cheapest solution. The downside is that it is a steel tank, not stainless, so it may not last as long.

I am in one of harder parts of NR3 mostly on wells, so I am going to buy a proper ion-exchange (ie salt) type softener.

I am also going to entirely replace the CH pipes. There is a lot of 10mm here, and as you said, it will need to be changed for the cast rads. The way the house is laid out, the simplest is to have a 22mm main, with a pair of rads on each of four 15mm legs, main and second floor, front and back.

I emailed Joule (you had recommended them before) about their stainless buffer tank (BBSSD-00300NFC) which has a better configuration of connections than the Gledhill (probably better quality too). With the Joule I could take the CH flow from a bit down the tank, the Gledhill has all the connections at the same height at the top. Joule gave me their list price (around 1400) and told me to contact a local retailer for their discounts. I contacted Plumbcity here and they quoted me 1900.

I am still looking for someone to install and notify the tank, and I am flexible about the parts I will do. Obviously the installer needs to do everything they feel is required to make it safe, probably the connection to the existing boiler, expansion tank, PRV (or TPRV) and termination. I will do the removal of floorboards, drilling through walls, the radiator piping, provide power, and so on. I need a boiler service anyway, so if you want come by, then you could do that and we could discuss it further.

Pm me your mobile number and address i will give you a call i am busy early part of the week but have time thursday or friday if it suits a few pictures of your existing system may help boiler cylinder ect , i use plumbcity if you forward me the quote i will see what discount they applied and may be able to help you out. Kind regards kop

fixitflav said:

How big is the house, no. of rads etc? For a normal sized place your system (3 pumps) looks complicated to me.

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You are correct that is it a normal sized house. Here is the 2-pump version.

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EvilDrPorkChop said:

Without reading the whole thread, what are you trying to achieve with this system?

You've only got one heat input so why not keep it simple and go down the route of a Unvented cylinder...

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I want to buffer the central heating system. The boiler will heat the cylinder and be controlled by a cylinder stat. The rads will all have TRVs and be fed by a smart pump, which slows when they close. There would be no room stat.

For those interested, here are the specifications for the 300l OEG tank. Sorry they are in German. They say the tank at 65C can deliver 175 litres of 45C water with a cold feed of 10C without providing any additional heat to the tank. It also says the tank losses are 1.6kWh/day.