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Replacing stopcock, which size

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1animal1

Aug 13, 2015
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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
 
20170812_191816.jpg
 
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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
 
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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
 
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
 
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.
 
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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
 
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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?
 
Did your plumber check the water pressure and flow rate as you require certain amount of pressure as well as litre per minute.
 
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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
 
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
 
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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
 
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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
 
king of pipes said:
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
Click to expand...

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]
 
Download the installation manual for the cylinder you are looking at fitting it all in there bud cheers kop
 
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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
 
So basically you've got 2 bathrooms, if so you should be able to supply to bathrooms with a combi boiler.
 
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?
 
1animal1 said:
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?
Click to expand...
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.
 
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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 🙂
 
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
 
1animal1 said:
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
Click to expand...

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
 
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
 
1animal1 said:
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.
Click to expand...
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
 
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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....
 
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?
 
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?
 
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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 🙂
 
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 🙂
 
Cheers Shaun, seems like you've given me a real credible alternative here.... Thanks.

I think the next step is to get this pressure checked first and foremost....

From reading, it seems I may still need this 22mm feed?
 
1animal1 said:
Cheers Shaun, seems like you've given me a real credible alternative here.. Thanks.

I think the next step is to get this pressure checked first and foremost..

From reading, it seems I may still need this 22mm feed?
Click to expand...

its best so just come straight out of the 20mm alk with a 20-22mm stop tap
 
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Excellent.... I'll try and source one. Should I bother my plumber now for just a pressure check given my 26/30 LPM readings?

Also... Should I direct all 15mm feeds to the various colds to where the boiler sits for post boiler balancing, or am I ok spurring off the 22 on the way to the boiler... Guessing the first suggestion so as not to reduce pressure to the new boiler
 
Combi boilers have improved alot another option is this one from Alpha innovations i recently went on a training day and was impressed with its output they had a working model there supplying 4 outlets at the same time , someone on here will shoot me down but personally i would give one of these units serious consideration , you can have a immersion heater added in the model with seperate storage and if it could be installed central to you property it would save on water useage.cheers kop

Screenshot_2017-08-14-06-12-53.png


Screenshot_2017-08-14-06-13-15.png
 
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Opened a right can of worms here 😀

Thanks kop. I'll certainly have a look at that.... My thinking is now cost orientated. Can I get two digital power showers going through a boiler with minimal heat change, integrate 2 CH rings with a nest on each, with availability to add one wet floor ring... The contingency of an immersion would be a bonus given the almost inevitable circumstance of the boiler going down at some point.

Worth pointing out that one power shower has a 3 metre minimal drop on 32mm pipework (couldn't get it any lower without major work due to stack location). So the flow doesn't need to be 30 LPM (obvious extreme). Also the climb to the furthest shower is probably 10 metres into the loft where it will connect to a digital mixer

The other power shower will be over a bath with what will be a 40mm waste if needed

Do any of these requirements rule any particular system out?
 
For this joint, the 20mm/22mm stops are none existent as expected. Think I'm going to have to go up with a Philmac coupler, into a 22mm bend, then run a tap after that....

I love a challenge
 
I could, but with the space I have, it would be a struggle.... With the Philmac I can get the piece to fit on the pipe, the coupler being 132mm tall (only question is how much mdpe I need to fit into it), 22mm bend, then the tap after that... Otherwise I'll have to site the tap further away into the garage. Least amount of connections and all that....

The bend is inevitable I'm afraid

Or 20mm mdpe stopcock, 20mm bend onto the Philmac... How do these plastic stop cocks fair for longevity? Compared to say a peglar brass 22mm?
 
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One plumber I work with insists on upgrading to 22mm on mains pipe at least as far as boiler and kitchen, reckons it improves performance of showers etc when mains fed. And as you say, megaflo needs 22mm.
 
Thanks gas

This will be going to the boiler. My plumber also suggested 22mm hot upstairs to both showers for that very reason, which I've laid in wait...

I've decided to relocate the stop tap in the garage, couple metres into the house and much easier to get to. Assume no issues in resiting this?

Just need to work out how to turn the outside main off. Found the meter grate with a plastic tap like thing next to it. Seems to just turn on a spindle?
 
Yes, I was thinking of an accumulator, that would help if someone ran a tap, shower, flushed the loo, or used washing machine at the same time as you were trying to have a shower. Replace 15mm pipes with 22 would ensure no restriction to flow. Worth a try.
 
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Fraid not Shaun, not yet anyway... Just got on my sun lounger . I'll post one a week tomorrow 😀

Stop tap currently comes up at side of downstairs waste toilet. So going to run 22mm into garage and mount a tap in there.

Cheers gas, Shaun had previously mentioned accumulator. That's now my primary choice with his recommended boiler, the Vaillant. Especially since seeing the lovely touch screen it comes equipped with.... Will probably save me buying two nest units for my duel circuits
 
Actually on reflection, I probably can't run duel circuits off the Viessmann (not Valliant)... I presume?

See below for picture of similar valve to mine

Screenshot_20170820-090407.png
 
1animal1 said:
Actually on reflection, I probably can't run duel circuits off the Viessmann (not Valliant). I presume?

See below for picture of similar valve to mine

View attachment 30666
Click to expand...


Just caught the end of this and only read the first page , hi flow combi could be the one instead of the unvented system ,, . 50l stored hot for when 2 outlets being used ,? May of already been said ,. Good luck
 
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1animal1 said:
Actually on reflection, I probably can't run duel circuits off the Viessmann (not Valliant). I presume?

See below for picture of similar valve to mine

View attachment 30666
Click to expand...

Dual circuits

And just turn the tap off (like a normal stop tap)
 
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I originally looked at hive.. it looks really good. I just think the nest is slightly more pleasing on the eye and more scalable with Google.... Nice tends to play to its own products from what I've seen.

What's your thoughts on them?
 
Without wanting to start a further thread...

Do you gents happen to know much about hot water loops? In regards to hot water reaching its destination faster and so using less water, wasting less of the cold in the loop that you'd ordinarily use in a normal hot water branch off.

I've done a bit of reading and can see that some countries use this a lot, especially where they suffer droughts. I'm obviously thinking of the hot water wait time, but like the idea of water save too.

As I'm fitting this new water main in the house, terminating at the new boiler site. I'm wondering if I should tap into the downstairs hot water to create a ring - I've already ran a new feed for upstairs - when that gets plumbed into the new boiler, we'll have the option to create a ring.

The reason I ask this is because I have read about some rings that feed the surplus cold water back into the tank for reheating which sounds a bit more complicated than what I am suggesting.

Thoughts?
 
You mean a secondary return

If it's a big house with a long hot draw off run then yes you need to fit one

Water regs say anything more than 30 seconds is a waste of water and need a secondary return fitting
 
Thanks Shaun, so that in its basic form is another access point to the ring. Simple as that...

Currently the hot water tank is located on the first floor, therefore there's a simple drop to downstairs and branches to upstairs. Guessing there's no complication in how the ring is formed.

I don't think the house is that big tbf. It's a medium sized 4 bed... But seeing as I'll have access to the pipework, figure it's worth hitting
 
Thanks Shaun.... That diagram is for vented, do i defo need the bronze pump on boiler/accumulator or unvented set ups?

Scott, I'm using speedfit on copper.... Are you saying that's not suitable?
 
Yes both the same the only thing that isn't on there is a check valve Normally fitted between the cylinder and bronze pump

And that's fine just can't use plastic pipe

Make sure it's well insulated
 
No probs... Is it worth bothering do you think, would the hot water coming through be that noticeable in a house this size? I'm fine adding the pipework but given the cost of the pump and added complexity.

The runs are mostly in the insulated garage. I've used the thickest foam I can get away with for the 22. Going to have to source some thinner for the 15mm due to my brackets restricting.

Quite involving this plumbing lark! Been at it all day trying to do as much as possible, getting access, laying pipes etc before having to turn the mains off and drain the Ch. 600mm to get through the garage wall! Massive pita
 
It definitely would. Only reason I haven't is, my trusted chap is always so busy, I'm always conscious of this so try not to trouble him unless I absolutely need to 🙂

Plus I enjoy it... There's a challenge around every corner! 😀
 
Morning chaps - Success! I have managed to replace the cold water main, hot next followed by the CH repiping.

Question - As I will be looking at a complete new system in Jan-April time - firstly, do new boilers tend to have their own magnetic and solid filtration?

My thinking at the moment is this - to fit either a second hand Magna to the 22mm pipework to cleanse the system prior to the new one being fitted.

The dilemma is, do i spend £40 on one of the few second hand ones on ebay as a make doo (best option if new boiler comes with one) or go and buy a new 22mm Magna, or perhaps the Magna pro 2 if it's worth the extra? assuming it will get used on the new system.

Thoughts please 🙂
 
Thanks Shaun! much appreciated as always.

Gathering the Adey 2 is worth the extra, what's the difference? - do they lose their effectiveness with age? and whats the service/shelf life of them?
 
I was just looking for best price and stumbled upon a thread from years ago....

Seems best I can see atm is £82 - amazing how some places are wanting £120 for the same item!

This won't be fitted optimally for the moment - I can't get it near the current boiler so it will be on the ground floor pipework - current system being upstairs fed - gather any crap from upstairs will always work its way downstairs with gravity and be swallowed up in this...
 
How do they work in comparison to the Magnaclean's - they don't seem to be magnet based, perhaps swirl pot style filter?
 
Update... I only had one option I could go for given its first location will be beneath the floor, and the flow on the return will be coming in from the top assuming the Adey or spirocombi due to them having to be upright . So I went with the MB3 separator in the end... Spoke with Spirotech prior to ordering for confidence in the filter material and the getting the right option. I had gone to them with the idea to buy the spirocombi sludge and air remover, but the flow wasn't in the right direction for my situation and the lady kindly pointed out that it wouldn't work optimally anyway... As a proper industrial set up by comparison would have the sludge remover on the return and the air remover on the flow... so I've managed to get the MB3 and RV2 for the price of the combi model @£115.... One place had this package, the rest all wanted close to £150 for both! Job well done I think...

Don't make me cry with a decent trade cost please 😀
 
Company called Viessmann Direct... Found it purely by chance. Even the eBay specials wanted £65 for the MB3's... The RV's were even more everywhere I looked
 

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