Replacing stopcock, which size

[1animal1]

Hi, I am looking to change my stopcock to a 22mm version. I am currently getting everything ready for my unvented system and figured I'd get this done whilst I've got the floor up downstairs re piping the bottom central heating ring.

The plan is to run the pipe into the adjacent garage which runs parallel with the hallway, so that I can line off to the necessary 15mm pipes going upstairs, and run to where the unvented will be situated at the back of the garage.

I presume the blue pipe in the picture is a standard 22mm and I'll need and compression stopcock?

Thanks

 

[Scott_D]

No picture

 

[1animal1]

Just trying to upload, won't open up the upload feature on my phone

 

[1animal1]

 

[Scott_D]

Its MDPE so wont be 22mm
Are you piping for a balanced cold?

Nice ballofix valve

 

[1animal1]

Not sure what you mean by balanced?

That's the only main into the house. Wanting to convert to 22mm as had read you need 22mm for unvented systems?

Guessing this will be 20mm mdpe given the relative size to the 15mm

It's a right mess isn't it I tried to tidy it up without repiping when refitting the downstairs toilet where it is situated. Knowing I'd have to take it all out again for the 22mm.... I was going to get my plumber to do that but figure I should be good if it's a simple compression fitting. That way it's all piped ready for the unvented install without me having to pull floors up again

 

[1Steven]

Bag o Rubbish re plumb.

 

[1animal1]

Googled it! And see what you're asking... Basically that the unvented is fed by the 22mm then all outputs balanced after the unvented? Presumably to ensure no one tap reduces flow on the rest

 

[1Steven]

Don't forget you're double check valve and doc for starters

 

[1animal1]

Doesn't all that get done with the unvented pipework?

Plan is, get the 22mm off the stop tap into the garage. T off to the upstairs bathrooms/current cylinder. Then T to the kitchen and downside loo running new closer lengths to where the unvented will be. When the unvented is ready to go, all can be repiped from within the garage making it easier all round.

Will this not work

 

[Jones82]

It will be either 20mm or 25mm mdpe, first thing to do is check your boundary stopcock works as you'll need to shut this off first to work on or before the stopcock inside the house.

 

[1animal1]

Will do, thanks J.

 

[ShaunCorbs]

will be 20mm

http://www.NoLinkingToThis/p/poly-stop-cock-20mm-x-15mm/98486

 

[1animal1]

Cheers Shaun... Any flaws in my plan to upscale to 22mm... About 7 metres to the unvented site

 

[king of pipes]

No disrespect 1 animal get your plumber to do all the pipework it looks easy but what your trying is a bit tricky cheers kop .

 

[1animal1]

No, i appreciate the advice kop.

What's the complication, the compression stop tap or the connections afterwards?

 

[king of pipes]

Theres not alot of point stepping up to 22mm off a 15mm supply if you truly want a 22mm supply you will need a new 25 mm mdpe main connected externally you can only get out what you put in upsizing will 15mm will reduce your pressure and flow , do it once do it right . cheers kop

 

[1animal1]

So the 20mm mdpe to 22mm is pointless when compared to the 20mm to 15mm I have now?

I get that the pipe diameter to 22 is increased from the 20, and so reduced pressure

Are you saying that an unvented system will need 25mm mdpe indefinitely?

 

[Old Account]

Did your plumber check the water pressure and flow rate as you require certain amount of pressure as well as litre per minute.

 

[king of pipes]

This is how it works 20mm mdpe to 15mm - 25mm mdpe to 22mm - 32mm mdpe to 28mm and so on .

 

[1animal1]

The pressure hasn't been measured properly, however it's not in question and my plumber agrees given what he has seen. It's easily above what is required for an unvented.

Kop, I appreciate the issue in upscaling a pipe with regards to pressure drop.

Am I correct in saying that my unvented needs a minimum of a 22mm feed... And if so, my only way to get this is to increase my main to 25mm? Given my 20mm predicament

 

[Old Account]

I hope you and your plumber know what they are doing. If not measured properly how do you know that you will have the right amount of pressure or flow rate ? I guess things like this should be fully checked before starting to think of an unvented cylinder. Some people Have 2.8 bar standing pressure but once you open a tap it goes down to 0.9bar so you really should check that

 

[king of pipes]

Yes mate it is if you want the performance stated by the unvented cylinder manufacturer in their instructions , you can still go unvented just connect to what you have obviously you wont get the litres per minute of a 25mm 3 bar supply but it will still work just not very well its your choice in the end . cheers kop

 

[1animal1]

Thanks match

So far my plumber who is qualified to fit unvented has only carried out a service on the bag that is my current 1986 boiler. He asked me a few questions regards pressure drop before checking himself visually.

My concern and reason I want unvented is because of pressure drop on the hot, that you get with most combis, which I don't seem to get on my current cold irrespective of what's being used.

I admit it needs measuring properly... But the advice I've had so far, I'm happy with based on mine and their experience

 

[1animal1]

Yes mate it is if you want the performance stated by the unvented cylinder manufacturer in their instructions , you can still go unvented just connect to what you have obviously you wont get the litres per minute of a 25mm 3 bar supply but it will still work just not very well its your choice in the end . cheers kop

Thanks kop

Sounds like the 20 versus the 25 will be really noticeable. This throws a huge spanner in the works given the work required to upgrade.

Max I'll ever need to compensate for is 2 digital showers running. Can i survive on the 20, or do I need this 25....[/QUOTE]

 

[king of pipes]

Download the installation manual for the cylinder you are looking at fitting it all in there bud cheers kop

 

[1animal1]

I'll have to get hold of my plumber as it was his recommendation I was going with on the cylinder.

Cheers for all the help. The intention was to get as much done prior to bringing him in around January time. Looks like I probably need more info before touching anything

 

[Old Account]

How many bathrooms do you have ?

 

[1animal1]

It's only a 4 bed with main bathroom, en suite. I had considered a second en suite but that's unlikely at this point.

 

[Old Account]

So basically you've got 2 bathrooms, if so you should be able to supply to bathrooms with a combi boiler.

 

[1animal1]

I've covered this with my plumber, I want the hot at mains pressure for a proper shower experience that a combi cannot provide. Unless the newer combis can provide that sort of pressure now to support an electronic power shower mixer?

 

[Old Account]

I've covered this with my plumber, I want the hot at mains pressure for a proper shower experience that a combi cannot provide. Unless the newer combis can provide that sort of pressure now to support an electronic power shower mixer?

A combi boiler is able to provide you a decent shower without lack of water pressure unless you open 2 showers in the same time then the boiler will provide you half. Which means if the boiler will give 16lpm you will only get 8lpm at the shower. Other than that there is no issues.

 

[1animal1]

That's the biggest issue, the drop off when using any other mains hot water source.

I have considered both and obviously don't want to spend more than I need to, but the unvented seems to tick all the boxes.

The final system will be a 2 zone with hot water and respective nest control. That's what I've settled for and what I am halfway through piping for... Although a bit of a pita as I'm having to pipe as I want it in its final guise, but then link it all together to work now with the current set up... Bags of fun

 

[ShaunCorbs]

get the flow rate and pressure and then come back to us

 

[1animal1]

Will do Shaun

 

[1animal1]

Ok, I've ran the 6 second test at the kitchen tap which is about 10 meters from the stop tap, and again at garage mounted tap about 1 metre from the main. Both with and without an electric shower running. 13 LPM is what I can deduce... So I'm miles away!

Tried again with two toilets filling and it dropped to 11 LPM

Just about to order a pressure gauge to test pressure.

Guessing I'm screwed at that

 

[Old Account]

Ok, I've ran the 6 second test at the kitchen tap which is about 10 meters from the stop tap, and again at garage mounted tap about 1 metre from the main. Both with and without an electric shower running. 13 LPM is what I can deduce... So I'm miles away!

Tried again with two toilets filling and it dropped to 11 LPM

Just about to order a pressure gauge to test pressure.

Guessing I'm screwed at that

I have told you before you should testing the lpm and the pressure ( standing/operating ).

Doesn't look to good with what you have got

 

[1animal1]

That's what I'm ordering a pressure gauge for as mentioned above.... There's no way to test pressure without is there?

 

[Scott_D]

Do these other taps have ballafix valves?
Flexi pipes?
Other restrictions?

 

[1animal1]

Yep, all taps and toilets have Flexi pipes and valves in place. I did try the garage tap which is actually less than a metre away and straight off the pipe... However less accurate as it takes a lot more turns to get full flow from it.

That gave me 14LPM

 

[Scott_D]

The pressure hasn't been measured properly, however it's not in question and my plumber agrees given what he has seen. It's easily above what is required for an unvented.

Are you testing from the same place as this?
For a true reading take the pushfit bend off above the stop tap, put a piece of hose or pipe on and test from there.
The house may be full of hidden gems like the restrictive ballistic valve

 

[1animal1]

This was from the kitchen tap....

Will do as you suggest, try without restrictions. I may try the garage one again with two buckets... Chuck one under for 10 seconds then remove....

 

[1animal1]

Latest on the garage tap is 14 LPM running on full.

Would it not be useful to try a new stop tap on 22mm given that my 20mm is reduced to 15mm prior to the stop tap already?

 

[1animal1]

Edit.... Just realised when looking at the picture at the start of my own thread, I fitted a ball valve and it was only half on!!! This is between the garage tap and the main.... Anyway, 2 tests... 26 and 30 LPM... Winner!!

Question for you chaps.... Just been talking to my neighbours who both have big combis running decent sized power shower heads, with no noticeable detriment when using another hot in the house.... I think my view on combis is based on a crap one in my old house that didn't pump very well and was notable when using a hot tap whilst having a shower.

I'm guessing combis have come on quite a bit!? Is it possible that a modern combi can run two power showers? And can I power two electronic valves for two central heating rings (2 nests) with a decent sized combi?

 

[ShaunCorbs]

if you have the space viessmann 222 with a properly designed system with maybe an accumulator you would be golden

 

[Scott_D]

Did you fit the one with all the PTFE on?

 

[1animal1]

Thanks Shaun. The unvented was going to be situated in the back corner of the garage, so I imagine it'd be similar footprint? This seems to be a halfway house.... What's the efficiency like compared to an average unvented? And is there a contingency should the combi stop working for hot water?

Yep, that's mine with the PTFE Scott. It's entirely hidden so didn't need to be neat

 

[ShaunCorbs]

yes same foot print and the same if not better but no, no elec immersion

 

[1animal1]

Apart from the lack of emersion and annual service, what's the downside compared to unvented?

Imagine the cost will be similar given the outlay for the unit (I had budgeted £3000-£3500 for the unvented).

And can I use with 2x CH rings with a potential underfloor add on..... And nest

 

[ShaunCorbs]

other than less stored water non

speak to your installer but should be

and yes