Gas Supply for New Boiler

[eyeofthebeholder]

Hi Guys,

Have just had a local plumber round to give us a quote on fitting a new boiler we have already purchased (Vaillant Ecotec 618 System)

The feed from the meter is 15mm throughout to the existing gas hob and boiler. The connection out of the wall to the boiler looking to be reducing it to 12mm(??).

He is stating that with the new boiler, 22mm will have to be installed from the meter and then reduced at (or close to) the boiler down to 15mm.

I have read the install instructions for the boiler and it states the incoming has connection is 15mm and also, from the Gas Supply requirement section: 'Pipework from the meter to the boiler must be of an adequate size. Do not use pipes of a smaller size than the boiler gas connection (15mm).

Is what he is saying correct, or just 'best practice'. Is it breaking regs etc??

Thanks

Adam.

 

[corgiman]

If he has done the calcs then he is right and as I cannot see what he can see I can neither agree or disagree.

dont you trust his professional opinion?

if not get someone who you do trust.

 

[Gasguru]

Even 22mm may not be sufficient, it's often necessary to go up to 28mm (and sometimes bigger).

Forget what the manual says - they're written by idiots. Gas pipe size is calculated to comply with the law, only a 1 mbar pressure drop from meter to appliance is allowed; the fact that the boiler has a 15mm connection is completely irrelevant.

 

[eyeofthebeholder]

He hasn't done any calcs - just came straight out with it - you need 22mm. It just sounded as though it was a standard thing that all boilers need now or new regs.

It's not that I don't trust him - he comes well recommended and has also worked on a system I had in my old house.

The reason why I bring it up is due to the hassle in fitting a new pipe in the house and also the info in the manual which looks as though it states you only need what is coming from the gas supply - but don't reduce it.

Also (for what it's worth) the house is only 28 years old.

 

[eyeofthebeholder]

Even 22mm may not be sufficient, it's often necessary to go up to 28mm (and sometimes bigger).

Forget what the manual says - they're written by idiots. Gas pipe size is calculated to comply with the law, only a 1 mbar pressure drop from meter to appliance is allowed; the fact that the boiler has a 15mm connection is completely irrelevant.

So I assume the only way of figuring it out is to attach a meter to the end of a pipe or something?

 

[Terrywookfit]

You should already have one!

Usually a U6 or E6 !!

 

[Gasguru]

When I say "calculated" the reality is most will use judgement and experience. The actual calculations/tables that the industry should work from are wildly inaccurate and result in gas pipework considerably undersized. Unfortunatley the majority of gas pipework installed in existing installations is undersized. This can result in safety implications hence the maximum drop allowed.

Use the forum search..this subject has been done to death. No-one likes the expense (that can be significant), the upheaval and often the eyesore of a shiny new 28mm gas pipe running around the ceiling or skirting.

You appear to have the hob/oven tee'd of the gas run. Unless the boiler is very close to the meter (say 3 or 4 meters) even 22mm is likely to be insufficent.

Once the new boiler is up and running the gas pressure is measured at the meter test point and the boiler test point with all appliances running flat out. Only then do you know if the pipe size is sufficient. Judgement is also required at this stage since each boilers test point is located differently; some gas/isolating valves can be restrictive so a few more mbar is lost.

 

[bengasman]

If you have found an installer that will fit a boiler you supply, don’t give him too much hassle. Most installers will only fit a boiler they supply. Do remember he will only install, any issues afterwards are your own problem. if the boiler brakes down or does not function for some reason, he will not have to warranty it.

 

[gas4you]

This boiler has a maximum gas rate of 1.9m3/hr, so this is what he should have based his alculations on, along with any other gas appliances that are using this pipe run as well.

 

[corgiman]

Arent we getting a bit techy lads

at the end of the day we are not the boyo on site making the call, the rgi is and the OP doesnt believe him.

as I said before it would be better if the OP contacted someone whose professional opinion he would trust rather than giving us all a chance to show off

 

[bengasman]

Arent we getting a bit techy lads

at the end of the day we are not the boyo on site making the call, the rgi is and the OP doesnt believe him.

as I said before it would be better if the OP contacted someone whose professional opinion he would trust rather than giving us all a chance to show off

hear hear

 

[Agile]

Clearly this OP would be happier with a cowboy who agrees to use the existing ( undersized ) 15 mm pipework.

One might wonder why he asks for professional advice here but apparently does not want to take it!

Perhaps if he was paying us then he might be better able to accept the good advice he has been given?

Tony

 

[bengasman]

it is not that he does not trust his installer, he just does not believe him

 

[eyeofthebeholder]

It's not that I don't trust or believe him.

I simply came on here as a kind of second opinion (is this such a bad thing) and also to find out more information about the situation - surely this is what this forum is for?

As it turns out, according to one of the more helpful comments, it seems that even 28mm MAY not be enough. As this is the case, I will now speak to him and also get a second opinion from another fitters to see for sure.

The basic gas run is as follows:
From the gas meter the T piece is a 12m run - basically running from the front to the back of the house. From this, there is about 1m run to the hob and 8m run to the boiler.
As far as I am aware all of this is 15mm pipework. I can not check for sure without chopping out walls and concrete floors - a plumber may be able to check the gas meter connections etc??

But anyway - thanks for your advise. Obviosuly I need further opinions from people onsite

Ad.

 

[Nixt]

No need to get opinion when you have a fact - Your pipework is undersized.