Gas pressure problems, use of MDPE pipe outside?

[Brian99]

Hi,

I've just had a new combi boiler fitted in my bungalow (37kW) and the existing 22mm pipe (routed through the loft) is not good enough to maintain the pressure and support the gas flow (the many elbows don't help here and the loft is now converted so cant gain access easily!). Gas meter is outside on gable end.

My only option seems to be to run an external 28m pipe round the outside from the meter position to the boiler (approx 20m) but I do not like idea of an external copper pipe on grounds of electrical safety, asthetics and the very real threat of copper theft.

So, my question is, can I lay an underground MDPE plastic pipe and have this made off onto the meter and boiler? What joints are required and can MDPE be brought into the hosue? My plumber suggests plastic cnnot be used, but as its all UG I can't see why not. :icon12:

Incidentally, the gas board were called in as the presure at the meter was also way too low and they have instaled a biger plastic pipe in place of the not so old plastic pipe. They were prompt though.

Thanks.

 

[Halesowen1]

Worcester boilers are probably the best for this, you dont get many Worcester boilers with more than 1mb drop anyway. Ideal are horrendous, I fitted one of these within 2m off meter, 22mm x2m and it dropped 2mb. Rang Ideal and they told about new allowed drops through valve.

 

[Halesowen1]

I dont think it is a smokescreen, some boilers like Worcester dont lose any through the valve, but others do and lose 2mb.

 

[AWheating]

well its a smokescreen because some engineers use the figure to justify poor work and having 16.5mb WP. If i was a customer who's 1 year old boiler had a NCS/warning notice on its anual service i would not be to impressed.

 

[< 0.004 = :-)]

When the reg is outdated I am sure it will be changed, untill then its best to stick to them. Do you note on your gas cert for the boiler that the Brand New Boiler you have just fitted for the customer is Not to Current Standards?? (You cannot fit a new appliance not to current standrads, that rule is for existing)
No you dont.............. So then you are getting deeper in it.

you can install a new appliance ID, never mind ncs if you don t know what your doing. had an LLSC y-day on a property with a new boiler fitted in june. 2mbar drop on an e6. asked tenant if any whiffs of gas, yeh sometimes in the kitchen where new boiler fitted. traced it to leak at the isovalve,. olive squashed into fitting. repaired it and completed the cp12. riddoring aint for me though, leave that to the gas polis.

gas cert for the boiler ? we don t need to notify in Scotland.
fill out the commisioning sheet , with GR/HI, IP/WP and CA results blah blah .
not a chance WB,BG,Vaillant or any large co., who can afford to employ expensive lawyers would leave theirselves exposed by not condemning appliances operating perfectly with lower than stated WP. if there was the slightest safety issue , they be AR-ed to CTA.

do you think gsr are going to come after you if you can prove a boiler is operating safely and to full performance , with more than a 1mbar drop ? they would laughed out of any court.

 

[< 0.004 = :-)]

say this one more time , but i doubt the penny is going to drop here .
the 1mbar drop is an outdated reg , from the days of se pre aerated burners.

i m mainly talking about replacing existing se combis with condensers. when going by the book , the gas should be at least kicked off in 28mm. houses that have finished hardwood floors throughout. a total nightmare to upgrade to acheive max 1 drop. and with 4 appliances , meaning a 20m run from meter now becomes an 80m for your calcs to acheive max 1 accross whole installation with everything running at max if we re doing it right (that bit confuses a lot of fitters) and not being cowboys remember, the costs become frightening.

if a boiler with a pre-mix burner works to Manufacturers spec ie , Gas Rate is Spot on , CO2/Co ratio, DHW temp rise etc on an existing supply (swapping standard for condenser, combi-combi) why would you insist on upgrading the gas first ?
would you not say to customer , going by the calculations , i may have to upgrade the gas to acheive a 1mbar max drop to fully comply with current regs blah blah, but this will involve upheaval and expense. the alternative is to install the boiler first , carry out checks, if not acheiving full permormance and it s undergassed i will need to upgrade it. if however it does not require upgraded to achieve full performance, even though your calculations tell you different , then obviously the calculations are costing your customers money they do not need to spend and you are the cowboy Matt Albright is more likely to take an interest in , than the sensible engineers taking he logical approach.

 

[< 0.004 = :-)]

Worcester boilers are probably the best for this, you dont get many Worcester boilers with more than 1mb drop anyway. Ideal are horrendous, I fitted one of these within 2m off meter, 22mm x2m and it dropped 2mb. Rang Ideal and they told about new allowed drops through valve.

new ideals and glow worms have a test nipple on the isovalve , takes away any doubt. bit nippy if boilers been boxed in underneath though, joiners , aaarrrrgggg lol

 

[Halesowen1]

So basically you are saying that you are not going to abide to Gas Reg's??
Well you go ahead.
P.S Looks like your horse needs some water...................

 

[Halesowen1]

If its an outdated regulation I am sure it would have been amended or removed. As all us fitters know the reg's can change from day to day.
But again i will say it, if you want to carry on breaking reg's then do so.

 

[fuzzy]

op says we cannot run bonded pipe outside, so its all academic.........mmmmmmmmmmm

 

[mikimac]

op says we cannot run bonded pipe outside, so its all academic.........mmmmmmmmmmm

If that's the case we should all be rushed off our feet 'cos there's plenty of it around...prepare for a payday guys n gals :rolleyes4:

 

[< 0.004 = :-)]

So basically you are saying that you are not going to abide to Gas Reg's??
Well you go ahead.
P.S Looks like your horse needs some water...................

lol , 20 odd years in the game mate, this thread is the first time i v been called a cowboy.
rollin , rollin , rollin

i don t set out to break regs and always try to follow them , but sometimes a bit simple common sense, experience and engineers discretion are also required.
so do you calculate IV for purging on every install ? if not then you must be a cowboy , no?
i know you would ve been delighted to find a gas leak on an inspection and riddor the installer, who would ve probably lost his job. if i knew him i d have gave a phone, but i aint going to grass him up. it may actually have held a TT when the job was completed, who knows. it was a very small leak, couldn t find it with LDF, traced it with the sniffer, the tenant must have a great sense of smell. 8mb permissable on an exsiting with E6 and appliances connected (its 6 month old, i did not install it so its existing), and no i wouldn t leave a new install of mine with any drop. we re gas engineers , not the polis, shouldn t fall on us to grass up other engineers.

 

[tamz]

If its an outdated regulation I am sure it would have been amended or removed. As all us fitters know the reg's can change from day to day.
But again i will say it, if you want to carry on breaking reg's then do so.

It is an outdated regulation and will be changed. The British Standards don't change from day to day, they take a long time and a lot of consultation before they do.
The current 6891 was published in 2005. Band A's were not the norm then.
ZPG's have changed a lot of things and ways of thinking.

 

[AWheating]

Changing the regs to suit one type of appliance would need very careful considerations as it could lead to many poor installations. Many engineers dont need any more excuses to avoid altering gas pipework and i would expect to find more installations with appliances competing against one another which could have major problems when appliances without fsd's are starved. I guess we will see what happens.

 

[tamz]

I guess we will see what happens.

That is true.
Cleverer people than us decide what is best.

 

[fuzzy]

If that's the case we should all be rushed off our feet 'cos there's plenty of it around...prepare for a payday guys n gals :rolleyes4:

yes there are many, im waiting for op to clarify his statements, he has agreed to do so without fear of prosecution

 

[Brian99]

as they must be bonded anyway can anyone tell me what difference it makes to have the copper pipe run outside?

Sorry, I’ve been working away last week and see there’s been a lot of discussion in response to my question. Thanks for all the positive points of view and healthy debate.

I feel I should reply to the discussion points about my statement of risk with exposed metal work outside a building. As I’ve said this is only one of the reasons why I’d prefer to have an outside mdpe gas pipe from the meter to the boiler.

The electrical dangers here shouldn’t be confused with the bonding requirements for services within a dwelling as these are very specific and are needed to reduce danger within the home as discussed below.

The wiring regulations use terms like “Persons shall be protected against dangers that may arise from contact with exposed conductive parts during a fault” they also have requirements to limit fault current magnitude and duration to such a level as will not to cause danger. With this in mind, consider the following: -

Danger can arise when any metal work, be it a copper water pipe (with tap), copper gas pipe or even an outside metallic security light is fitted to a building where the electrical service to a home uses the combined neutral/earth arrangement offered by the electricity supply company. Why? If a neutral fault occurs the earth conductors of the whole installation can become live at a voltage above true earth. As most users of this forum know, the wiring regulations call for equipotential bonding within a building (gas services included) to reduce the risk of injury in these circumstances, but this measure is only effective within the building. If this metal work is taken outside (e.g. gas service in copper around the house or a copper water pipe and tap) a person can make contact with the metal work and if this is during a neutral fault, can receive an electric shock. Of course, this may also occur inside the house but the risk of receiving a leathal shock is reduced through equipotenial bonding and generally having a dry and carpeted environment. Outside is a different matter altogether and in the extreme, a child grabbing hold of an external water tap in bare feet standing in a puddle of water (during a neutral fault) could have lethal consequences.

Before a reply comes back with “the RCD will protect” argument, it won’t. If the neutral fault is on the mains side of the cut out the earth will become live and this conductor will pass current through the person “holding the outside metal work” to true earth, completely bypassing the RCD.

As a disclaimer, if anyone wants advice about specific installations you need to consult a qualified electrical contractor as this discussion is of a general nature. Hopefully it will enhance debate and questions leading to a safer environment.

I'd also like the comfort of knowing the mdpe pipe I'm laying for my gas safe plumber to connect is within regulations and is one of the better options I have open to me.

Thanks for the responses and keep the debates going.

 

[AWheating]

the risk of shock is no different from being inside the house to outside imo, the pipe is bonded either way, you are more likely to wear footwear outside than in and although moisture/rain may decrease resistance to earth it wont make a major difference. If you have a situation where your earth has a live current you will more likely get a shock inside off any bonded metal work like a radiator, boiler etc... then brushing against an outside pipe.

You will have metal pipework at either end of a mdpe run anyway which can be touched outside and the break from copper to plastic will mean part of the gas pipework is no longer bonded which is worse.

 

[fuzzy]

what about a radiator in a bathroom, putting the towell back on the rad when you get out the shower, naked and wet. surely this risk is as much if not more than an external copper pipe run. If it is bonded what is the difference? i see the risk as the same, please inform me as to why it isnt

if there is a fault to earth wont the rcd trip off regardless of anyone touching it? thought it measured what current went out and what comes back, if not the same it trips (in simple terms). So a properly bonded pipe would send the fault to earth and trip the rcd, inside or out?

Please tell me if im on the right lines or not

 

[stani]

are we not getting confused with not being able to use a pme system to feed a caravan, this can have an effect, and in these conditions then the system must be made into a TT system and an earth rod used, I cannot for the life of me find any information relating to external copper gas pipes or even external water pipes.

 

[fuzzy]

any update please op

 

[TerryWaite]

use hep20 its rated upto 15 bar so will easily take the pressure, use metal cable ties every 2 metres so it wont move, make sure you put a ballfix valve on it too for icelation

 

[Reg Man]

Hep20 for gas? I don't think so! Not approved unless ive missed something. Ithink you must be refering to water pipes.

 

[fuzzy]

think it was a joke reg man

id still love to hear from op