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.

 

[chris watkins]

Of course what pappasmurf could / should have done in the first place, IMHO, is engaged the services of a CIBSE mechanical consulting engineer who would have sat down with him, talked through all the different options & come up with a design which he would have then owned & it would have been backed by PI insurance in case things went wrong.
He could have then used this design to get heating companies to tender like for like for the work required.
He might not of liked the bill for this service mind you, much easier to walk over the road & have a look at the neighbours place & rely on the local poorly trained plumber or a forum to fill-in the rest.

 

[Gray0689]

Never a truer word spoken chris I agree 100%

 

[pappasmurf]

Then you will need mechanical mixing valves on all manifolds and pumps

Gray0689 which mixing valves are you refering to?... as the underfloor heating manifolds already have automatic mixing valves

 

[Gray0689]

That's the mixing valves I on about

 

[pappasmurf]

Gra0689 please read your reply above! is it a typo?.... i dont understand as i said the "automatic" mixing valves are already installed on the undefloor heating manifolds!... so pls tell me which mixing valve/s u are talking about?

 

[Gray0689]

The ones on manifold
There only attached to manifolds you can get them without
Mate you need to get someone in to help you as your going to get yourself in a muddle as you have a little knowledge and that can be a dangerous mix sometimes
And I mean that in a nice way

 

[on31ll]

i subcontracted for a friend while he got back on his feet ethel austins took him for £175 k ! when the people with the money sorted it they offered him 3p to the pound

 

[vern]

I will keep it brief as you really need someone on site!

Option 3 ......Junk the 24 Ri ,bash in a 40 CDi (actually 41KW) no LLH Commercial spec grunfos pump for primary's say 42mm copper so 11/2" flanged, 4 zone valves (DHW,1 for each UFH Manifold) with autobypass honeywell DU146........5 pumps = 1 x main 1 x bronze secondary 3 already fitted on UFH manifolds, ensure megflo has a balancing valve fiited on return from coil, to obtain 20 deg diff, as 1/1/2" pump will send it through the coil too quickly on DHW mode only, Autobypass will sort the rest, and UFH manfiolds will look after themselves due to mixing valve etc...........
Aww Cr@p book me a hotel!!!!

Heres a crap blackberry picture of a 4 zone system with a 250L Megaflo, with bronze pumped secondary return, it was powered by a 40CDi not in pictures.....this gives you an idea of the room required to install such equipment so be aware of that issue....note these pics were a year on taken on 1 service, note the lagging was supposed to be done by customer as he said why pay us to do a job he could!!

The UFH Manifold was remote mounted under the stairs and just did a 9 zones on the ground floor, second floor was radiators, 1 bathroom and 2 en suites.

lol just seen our sticker peeling from Magnaclean!

 

[Gray0689]

9 branch manifold on 22mm pipe mate!

 

[vern]

9 branch manifold on 22mm pipe mate!

Lol well spotted pal, long story short......small 9 zones e.g downstairs W/C, utility, hall etc, nothing was common'ed up, we did not do the under floor, he contracted it out, also the house was all 1st fixed in hep20 back to the garage, just above where you can see the zone valves, by a plumber who bottled the job and did a runner, luckily he had labeled all the pipes 1st, so 22mm was all we had as all the walls were up and plastered, solid oak skirting etc.....by the time we were involved!

This was a get it finished job and the customer understood we were only liable for the work as the pictures in the garage, this is what happens when you try to save money by employing loads of different contractors on a price! Hence the lagging never got done, in fact 2nd service due anytime so we will see.

BTW the UFH works a treat..... I asked on 1st ASV

 

[Gray0689]

Well nice work either way mate I'm impressed

 

[vern]

by a plumber who bottled the job and did a runner

This was mainly to highlight to the OP what can and, indeed does happen when the jobs a bit out of the ordinary....
One word recommendation, but not his neighbours lol....
The plumbers in question did a runner because.......
1. They were out of their comfort zone
2. They forgot to 1st fix F&R pipes to bathroom, and 2 en suite towel rails, this was not spotted until the floors and walls were all tiled and grouted and suites 2nd fixed! I am talking nice bathroom and en suites too £40K + worth, so how do think said rooms are heated? Yes an above door electric nasty £99 blower!
3. They had just got a stage payment
4. We started mid October and they had to be in for Christmas.....we got done in less than 4 days, including chasing a mate at Northern gas networks to bump up the list his gas service and meter install, but you should have seen the panic as he had completion clauses with clawback for most of the other contractors

 

[Gray0689]

Lol like the sound of the nice blow heaters (NOT) lol

 

[vern]

Lol like the sound of the nice blow heaters (NOT) lol

Looked a treat pal lol, such a shame really but when the customer starts using too many chef's!,

look at our pipework, we would normally use M10 rod with a rail and brass Munson rings, but we had to use the talon clips and spacers, as this is what was there to use! To use the gear up on site and cut costs!

I refused to use the Grundfos 15/50 pump that was on site though..... or I was walking off the job

 

[Gray0689]

Yes prefer school boards and Munson rings myself mate
But plastic o the job
Just depends what they want to pay!!

 

[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.