How long to replace a Vented Cylinder with an Unvented one

[Worcester]

We are always looking to improve our efficiency (and hence money in our pocket )

Just wondered how long most people would estimate for a replacement of an vented cylinder with shower pump to an unvented balanced supply system?

x man hours / days?

Assuming straightforward, i.e mains supply nearby (well it must be to the header tank at least ) no upgrades to DHW heating controls (use existing timers) primarys in OK location for new cylinder, and straightforward access to cylinder location, i.e. average, typical cylinder replacement. Plastic cold water cylinder (aka tank) also to be emptied and removed in pieces from loft (hatch is always too small )

Thx

 

[lame plumber]

long morning to 2 days, all depends on what ****ty problems you get on the way, so I always allow a couple of days

 

[Killy Bing]

Hmm, decent apprentice cuts the time down. If they know their pipes and what to do in the loft they can sort that and fetch you whatever you want.

 

[Ermintrude]

4 to 8 hours on a good day. But when new sl800 won't fit through 450wide bifold doors it takes longer.

 

[lame plumber]

4 to 8 hours on a good day. But when new sl800 won't fit through 450wide bifold doors it takes longer.

or when the apprentice appears in the airing cupboard fm above as happened to a mate

 

[Reg Man]

How long is a piece of rope, every job is different. As lame says, two days on average, for a simple one. Running D1, D2, tying up all the pipework, disconnecting the storage facilities and disposing.

 

[Nostrum]

Depends on D2 run really and how much work is needed for balanced cold take off.

 

[Worcester]

Thanks guys, ours are never simple and we're finding that most take a couple of days, thought we must be missing a trick though. - There again, the D2 took a whole day today (taking up bathroom floor covering, then the floor boards, drilling from the outside, then across and under the bathroom wall putting the floor boards and flooring back and had to be in 28mm due to the elbows to get out of the airing cupboard ........) next week the D2 is straight out the loft to a high level discharge

 

[TBServices]

What do you guys normally do re: cw supply, and balanced cold?

It's usually 15 in the cylinder cupboard, in fact it may be 15 all way back into street.

 

[Reg Man]

Quote>next week the D2 is straight out the loft to a high level discharge <Quote. Are you allowed to do that? I do not think so.

 

[Worcester]

Quote>next week the D2 is straight out the loft to a high level discharge <Quote. Are you allowed to do that? I do not think so.

I believe you are So long as you return it to the wall ... Though it may depend upon your local building control officer

Downward discharges at high level ... are permitted provided that the discharge pipe is directed onto the wall to allow cooling and dispersion to take place onto the wall surface

 

[Mike Jackson]

Not allowed according to G3.

 

[kay-jay]

High level must be discharged into a stack or hopper

 

[cr0ft]

We always price unvented installs on 2 days of labour for our business. If you price for less and you hit a problem then you are screwed really, or asking the customer for no more money.

Hope this helps.

 

[Nostrum]

Used to be allowed to return to wall but that was scrapped quite a few years ago now. It was always considered a 'last resort' solution anyway from my understanding.

 

[Ermintrude]

Last resort is the cavity );

 

[Worcester]

Remember that the Approved Documents, are only one way of complying with the Building Regs - the nature of our work means that we end up regularly talking with and challenging Building Control officers - We had to teach them most of the 2010 changes re Competent Persons

The ONLY requirement of G3 is that "any discharges from safety devices is safely converyed to where it is visible but will not cause danger to persons in or about the building"

The Approved Document G gives some examples of how this can be done, if you follow those it is unlikely that you will be challenged by the BC officer, however, as it clearly states in the opening paragraphs ADG "include examples of what, in ordinary circumstances, may be reasonable provision for compliance with the relevant requirement(s) ..." it goes on to say that "following guidance does not guarantee compliance" and further says "that there may be other ways of achieving compliance" AND that "There is therefore no obligation to adopt any particular solution contained in this Approved Document if you would prefer to meet the particular requirement in some other way."

So in summary , there are no MUSTS to any particular way of managing any discharge, high or low... as I said, depends upon the particular installation's circumstances and your relationship with your BC officers

 

[spanner]

Haven't fitted an unvented system yet. But my big sister has 300ltr megaflo..the thing is. After cutting out all the old gravity pipework and adding to the existing old pipes ..you won't find any leaks under mains after a PRV..

 

[spanner]

And hi everyone.. happy new year and I'm so happy to be in with the new lads..

 

[Reg Man]

High level discharge in safe location against a wall is ok for sealed system boilers as the water content is lower and only likely to discharge the content of the boiler. Stored Unvented is an other matter, discharge to low level or drain and must be visible. B C officers who pass anything else obviously do not know what they are looking at.

 

[spanner]

Good morning..

 

[Reg Man]

Good afternoon

 

[GrahamM]

High level discharge in safe location against a wall is ok for sealed system boilers as the water content is lower and only likely to discharge the content of the boiler. Stored Unvented is an other matter, discharge to low level or drain and must be visible. B C officers who pass anything else obviously do not know what they are looking at.

Again it is the wording and is a bit of a grey area. Where have we heard that before?
G3 mainly states should terminate in safe, visible position where will not cause harm or damage. Just as a boiler PRV. Best practice would be into hopper etc if must terminate high level but I have let dozens go for being high level returned to wall and in my opinion as per regulations.
In absence of any clear, distinctive guidelines some guys will say yey others nay!
It does not state anywhere as far as am aware that MUST​ go into hopper etc at high level.

 

[TBServices]

According to my bpec book (4 years old) it's fine as a last resort, but not recommended

 

[Nostrum]

I did the re-assess last month and it wasn't mentioned in there at all as being appropriate. Yes you can choose another alternative to the approved documents recommendation but it will be on your head if someone is injured as a result. Nearly everything we learn or are told is not a regulation, but a standard to which we should work, the building regulations aren't at all specific.

Sometimes it's easier to stop fighting and go along with what your told, cover your arse and walk away knowing you've no come back.

 

[TBServices]

This is why we have to do reassessments I guess.

 

[spanner]

There you have it.. sorted

 

[Dotty]

High level must be discharged into a stack or hopper

Funnily enough I was testing the gas pipework today on an Andrews Ecoflo DFHWB which I'll be commissioning next week sometime, when I spotted the Logic course notes on top of the boiler.

And knock me down with a feather if the book didn't fall open on this page!

 

[spanner]

Funnily enough I was testing the gas pipework today on an Andrews Ecoflo DFHWB which I'll be commissioning next week sometime, when I spotted the Logic course notes on top of the boiler.

And knock me down with a feather if the book didn't fall open on this page!

View attachment 16664

Hi Croppie..

 

[Dotty]

I've seen you there Spanner, with your conspicuously shiny wallet and your inability to shout a round in......

I set you up a tab when you got given access.... You owe £37,943.67p

And that's before the others felt thirsty!

 

[chris watkins]

Remember that the Approved Documents, are only one way of complying with the Building Regs - the nature of our work means that we end up regularly talking with and challenging Building Control officers - We had to teach them most of the 2010 changes re Competent Persons

The ONLY requirement of G3 is that "any discharges from safety devices is safely converyed to where it is visible but will not cause danger to persons in or about the building"

The Approved Document G gives some examples of how this can be done, if you follow those it is unlikely that you will be challenged by the BC officer, however, as it clearly states in the opening paragraphs ADG "include examples of what, in ordinary circumstances, may be reasonable provision for compliance with the relevant requirement(s) ..." it goes on to say that "following guidance does not guarantee compliance" and further says "that there may be other ways of achieving compliance" AND that "There is therefore no obligation to adopt any particular solution contained in this Approved Document if you would prefer to meet the particular requirement in some other way."

So in summary , there are no MUSTS to any particular way of managing any discharge, high or low... as I said, depends upon the particular installation's circumstances and your relationship with your BC officers

The important bit is what comes in the paragraph after you finished quoting above, it is as follows "However, persons intending to carry out building work should always check with their BCB, either the local authority or an Approved Inspector, that their proposals comply with Building Regulations."
So to summarize, if you follow the AD guidance then there is a presumption that what you have done will comply (very importance if you are self certifying). If you do not follow the guidance & choose to do it another way then you need to check with building control that all is OK!!! (not much point in a self cert then). High level discharge which is turned back against the wall is not given as an example of acceptable discharge arrangement under 3.62 & therefore would strongly suggest that if you are thinking of terminating like this that you consult your local BCB first.

When the new Part G come out in 2010 we were issued with the following information / guidance on this, to pass on to engineers. As there was now the provision to terminate the safety valve discharge to a plastic stack it was very unlikely that high level discharging against a wall would be allowed. I still have this somewhere but for the life of me can't find if I stumble across it I will post it.

 

[Nostrum]

Well Croppie , spanner in the works!

 

[Worcester]

Whether you self certify or not - and we self certify for loads of different sections of the B Regs because of the wide scope of work we do, we find that having developed a good relationship with our local BC department has been well worth while, often we make just a courtesy call - then they feel empowered to advise, which gives us a chance to discuss, and no problems later on.

 

[Worcester]

Well you guys'll love this one... Had a discussion with Building Control today initially about D2 sizing and my calcs based on BS6700, at which point they said that I clearly knew more than they did, and that they were happy with what ever I wanted to do, discussion then got onto renewables, and I have now been asked to go and give the whole of the local BC department (3 District Councils) a talk on Renewables, our design and installation processes, and what to look out for

Their response email said "If we have any queries on renewables we now know who to call" - That's what I call a good relationship with the BC department :sunny:

 

[Ermintrude]

Under your thumb ! Probably want loads of free work from u now !

 

[chris watkins]

Well you guys'll love this one... Had a discussion with Building Control today initially about D2 sizing and my calcs based on BS6700, at which point they said that I clearly knew more than they did, and that they were happy with what ever I wanted to do, discussion then got onto renewables, and I have now been asked to go and give the whole of the local BC department (3 District Councils) a talk on Renewables, our design and installation processes, and what to look out for

Their response email said "If we have any queries on renewables we now know who to call" - That's what I call a good relationship with the BC department :sunny:

I tried the same thing with my local BC at Christmas offered to go along FOC in-between then & new year, bearing in mind how little they seem to know about un-vented in our area.
Did not even get a reply, I suppose it is just easier to keep doing nothing !!! signing things off even if they are wrong, cos at the end of the day they are protected from any legal action themselves.
What water velocity do you use Mr Worcester never tried it using 6700 (or should I now say BS en 806-3)

 

[spanner]

How much Did you weigh in with the pipe removal.. :29::13::29::clap:

 

[spanner]

Sorry you lot but I'm having an early night tonight been up since 4 am ok brb

 

[Worcester]

I didn't offer, they asked and I accepted, and it's renewables I get to talk about

Worked it back from available head (300+5mm/m over 9m) = 345mm with a pipe bore of 20mm gives a velocity of 0.7m/s and flow of 0.22 l/s - or 13.2 l/min the pressure and temperature release valve have to pass a minimum of 8.33 l/min so 13.2 l/min so OK, (that's therefore what the BS/PartG is based on)
If you look at the head loss of the pipe at those flows, you'll see that it also equates to 345mm/9000mm = 0.038m/m or 0.376kPa/m which ties up with the head losses in the pipes at those flow rates - so 'squares the circle'

Then simply showed that the actual hydraulic gradient was better than that so it would easily cope with the flow, so to answer your question in simple terms. 0.7m/s

In effect what this allows you to do is to discount any vertical drops in the pipe from the pipe lengths mentioned in the regs, so long as you maintain the fall and 300mm minimum..

Hope that makes sense