pipe sizes for complete heating/DHW system

[pappasmurf]

Can someone pls help...... just bought a new house. After major works and extensions (Rear and Loft), (next year), will be an 8 bedroom, 4 shower room (no baths), 2 kitchens with full underfloor heating on all floors in the house.

The system will have 2 Worcester Bosch 24Ri (heat only boilers); 1 for the DHW, 1 for the Underfloor heating. No header tank.
I have already updated my mains supply from the street to 32mm poly pipe. The pressure is approx.3 bar and approx.20 lt/min.
There will be an indirect 300lt unvented megaflow cylinder feeding all the DHW (4 shower rooms,2 kitchens).

What i need to know is what size of pipework should i be feeding this circuit?.... i have always assumed that in plumbing, the bigger the better!... is this so?

I was thinking of supplying the cylinder with this 32mm MDPE pipe and then on the outlet from the cylinder feeding the house with 28mm MDPE and eventually reducing to all shower rooms/kitchens back down to 22mm and then further to 15mm. is this correct? as i am hoping to ensure good/reasonable flow rates to all services as possible espcially if more then 1 or 2 services are used at the same time.
will i also need an accumulator up in the loft conversion?.... if so what size pipework will i need for this aswell?

The underfloor heating in the entire property will be piped hot from heating manifolds using the "Wavin" brand.

 

[Gray0689]

Lol it's amazing what people don't know about pump sizes they think the world revolves around a 15-50
I told a boy once he needed a new pump and he said he would get it himself
I went to change it
He got a 15-50 to replace a 32-120 lol

 

[pappasmurf]

whats the difference between munson rings and plastic?.... they both do the same job, dont they?... i mean just securing the pipework!... or is there some science involved that we don't know about?... please advis.

 

[Gray0689]

If you got a big set up you will have lots of pipes that go over under above so there better but plastic have a place to

 

[Gray0689]

whats the difference between munson rings and plastic?.... they both do the same job, dont they?... i mean just securing the pipework!... or is there some science involved that we don't know about?... please advis.

It's also a pride in your work thing

 

[SimonG]

In a boiler room install 'proper' fixings look better than plastic. It's got to look good on the bits that are on view, generally the cust only sees about 10% of your work. If that looks good then the chances that the rest is good are high.

 

[vern]

whats the difference between munson rings and plastic?.... they both do the same job, dont they?... i mean just securing the pipework!... or is there some science involved that we don't know about?... please advis.

Quite a lot actually!
1. Cost
2. Demountable for future maintenance many times over, unlike Plastic when they have done a few heat cycles the hinge breaks
3. Weight capacity it's not just pipes, consider pumps, zone valves etc.....
4. Adjustable via screwed rod to any dimension
5. Looks more professional because it is!
6. Utilising uni strut can be fixed to surfaces plastic cannot
7. Pride in the job
8. Easier to get proper sized lagging on, especially where pipes need to cross

Using your analogy I could fit remould tyres to my car / van "they both do the same job" they are both round and black you see.....BUT I never would!

No offence Papa but I think you want a Rolls Royce for mini money, hope your not offended as 90% of other custards do too!

 

[pappasmurf]

vern well i'm still gaining the knowledge from you guys
as it is i have just this evening got a quote from a plumber that came round the other day (seemed very knowlegable and have used him before).... His quoted me (Labour only) £10,500 for the whole job. thats fitting 2 boilers (Low Loss Header arrangement), 300L megaflo, full underfloor heating to the entire property,full plumbing for 2 kitchens (hobs/washing machines/sinks etc), plumbing all 4 shower rooms with thermostatic valves/shower heads/toilets/basins, etc. He said if i'm happy with the quote he would make a detail list of materials for the job. What do you guys think?.........

 

[Howsie]

You pay your money and take your chance.

I think that's quote seems very very reasonable. Where did you find him?

 

[pappasmurf]

I found him a few years ago when i was doing my existing house (downstairs full underfloor heating) from the polyplumb accredited installer website. He is quite good, and he does commercial aswell, thats why he has done quite a few LLH setups. Which really helps i have used him a few times since.
I'm gonna be going to the PHEX exhibition aswell on the 15th and 16th Nov. at Chelsea. might be able to hook up with some good guys there aswell who can give a few more quotes, just for comparison purposes

 

[TBServices]

I found him a few years ago when i was doing my existing house (downstairs full underfloor heating) from the polyplumb accredited installer website. He is quite good, and he does commercial aswell, thats why he has done quite a few LLH setups. Which really helps i have used him a few times since.
I'm gonna be going to the PHEX exhibition aswell on the 15th and 16th Nov. at Chelsea. might be able to hook up with some good guys there aswell who can give a few more quotes, just for comparison purposes

Why would you take a chance on someone unknown when you already have a plumber you trust? Take his quote and run with it IMHO.

 

[Destroyer2813]

Why would you take a chance on someone unknown when you already have a plumber you trust? Take his quote and run with it IMHO.

Because people wanna save a 10-20 note here and there and think they can get a better deal than what they are currently getting

 

[pappasmurf]

Destroyer2813 it's not about saving £10-£20 it's about gaining the knowledge!.... since i will be purchasing the materials, i can in-corporate and source the good stuff i.e LLH's... Munsen clamps/rings, etc

 

[Gray0689]

To be honest cant really say if reasonable or high as don't know what spec you talked about
Don't know size of house
Don't know spec of bathrooms
Make up of house ect

 

[Howsie]

Sorry I thought the £10k was just for training smurfy up.

 

[pappasmurf]

Gray0689 this is why i am also confused i need to get a comparison from other plumbers. the house "will" be a 7 bedroom (2 in the loft), 2 reception rooms, 2 kitchens and 4 shower rooms.
believe me i know this sounds like a mansion, but believe me its nothing of the sort! its actually quite small. when i mention 7 bedrooms to people immediately they think its massive!
the spec of each shower room is 1 shower head with 1 thermostatic valve, 1 basin, 1 toilet. and the plumber does not have to fit any of these facilities!... he just has to give the supply outlets for the builder to hook up.