New Boiler, and 15mm pipe?

[Andy165]

Nearly all manufacturers instructions require you to fit 22mm. gas supply to the boiler. These take preference

 

[namsag]

Difference being if new boiler is band A with zero govenor then it can become a very serious and dangerous problem

 

[Agile]

and so back to my original point that if you replace a 28kw combi with another 28kw combi there's a fair chance it will be fine, especially bearing in mind that the input will actually be lower on the new one.

I cannot agree with that statement!

Almost all boilers fitted 10 years ago had undersized gas supply pipes.

Its only in the last five years that CORGI became concerned by the gas supply pressure at an appliance.

Most boilers will work with a seriously undersized gas supply but if CORGI catch you then you will be up grading to 28 mm at your own cost!

Its stupid for a manufacturer to say that you need a 22 mm supply pipe without knowing the effective length!

Tony

 

[corgiman]

it may be stupid tony but thats what WB GW and vaillant say

not sure of any others

IMHO you have to get you tape out and do you sums to see what size Gas pipe you need

thats How I have always done it anyway

 

[Agile]

it may be stupid tony but thats what WB GW and vaillant say

Of course they know that if they say that then the non registered will think that its needed and not use the existing 15 mm supply in some cases. Thats the non-reg who can read english !

It probably saves them several hundred service calls a year!

Tony

 

[chrisdicko]

Thanks for all the replies guys I'm not trying to do things cheaper, although it would be better for me if it costs less I will trust what the plumber says, I was just curious really.

 

[Clive100]

Let's not forget that any new combi must be installed according to the manufacturer's instructions and ALL modern 28kw combis will require a 22mm gas connection. It's likely that the gas supply into your flat is 22mm and then hopefully branched at the kitchen into twin 15mm's i.e. cooker and combi. It will be necessary for the current combi 15mm branch supply to be traced backstream to the incoming and replaced with the required continuous 22mm supply. The cooker supply will also probably need to be rebranched to suit the new alteration.

 

[EliteHeat]

I'm not trying to do things cheaper

Of course you are.

You have already decided what unrealistic price you want to pay without knowing any of the issues.

I will bet anything that you choose the lowest quoted price safe in the knowledge that any undersized gas supply will have to be upgraded at the (huge) expense of the installer when you complain to Corgi.

 

[Agile]

I will bet anything that you choose the lowest quoted price safe in the knowledge that any undersized gas supply will have to be upgraded at the (huge) expense of the installer when you complain to Corgi.

I do have to say that brings a smile to my face!

There is no sympathy from me to any installer who undercuts quotes by not installing the correctly sized gas supply.

If some are then required to pay to upgrade their substandard work then it will teach them a lesson.

Tony

 

[mickyg]

I cannot agree with that statement!

Almost all boilers fitted 10 years ago had undersized gas supply pipes.

you obviously don't understand what I mean, I said if its ok now it may be ok for the next boiler. If its undersize already its not ok now is it

Its stupid for a manufacturer to say that you need a 22 mm supply pipe without knowing the effective length!

agreed and exactly the point I'm making

 

[mickyg]

If you have no more than a 1mbar drop from the meter in working pressure at your shiny new boiler then it does not matter what the size of the pipe is. It is true that quite often 22mm pipe is required to obtain this, but in my experience if you have a 28kw combi with the correct working pressure and replace it with another 28kw combi there's a reasonable chance it will be fine.

If only people read whats written before disagreeing with it

 

[mickyg]

Manufacturers Instructions for Vaillant ecotec plus range

The diameter of the pipework (7) is 15 mm. Connect a
gas supply pipe of not less than 15 mm diameter to the
copper tail.
Note
Ensure the gas supply pipework is adequately
sized so that a 20 mbar gas pressure is available
at the boiler inlet at full flow rate.

 

[chrisdicko]

I'm not trying to do things cheaper

Of course you are.

You have already decided what unrealistic price you want to pay without knowing any of the issues.

I will bet anything that you choose the lowest quoted price safe in the knowledge that any undersized gas supply will have to be upgraded at the (huge) expense of the installer when you complain to Corgi.

No I'm not. And to be honest if an installer fitted a new boiler and it worked fine on 15mm pipe I wouldn't give a toss. But if it didn't work, of course I'd complain. Not to corgi, but to the installer.


Clive100, thats exactly what he's going to do. He's just been round and we removed some paneling and floor boards, and found 22mm pipe right to the wall of my flat, and it goes in to 15mm pipe in a Tee to the cooker and boiler, so he said he'll change it at that point to 22mm. Also he said if that still doesn't give the correct pressure he'd have to start at the meter in 28mm.

 

[tonybhoy]

Not up to you to decide it's down to the installer to get it right. Most times punters wouldn't have clue whether the boiler is working properly or not.

You might have difficulties running the odd bath in the coldest days of the winter but you would easy to fob off with the old 'ach it's a combi ,they do that at this time of the year routine'.

Your guy sounds as though he knows what is required though.