Gas Pipe question 22mm to 15mm

[DIYer]

Hi all,

I have a gas pipe running to my boiler which I think is 22m then reduces to 15mm about a meter before it enters the boiler. When I look from underneath the boiler it looks like there's another 22mm pipe running horizontal over where the 15 mm bit goes in.
Was wondering if this is correct ?

Also wondered about how much it would cost to have a new 22mm pipe fitted in place if the 15mm? It'seems about 2 meters long with 1 bend and will probably need a couple of elbows.

Cheers

 

[Scott_D]

Any pics?

 

[townfanjon]

If the boiler makes the required pressure its fine

 

[Riley]

Pics please. What do you think is wrong with it

 

[Harvest Fields]

Is it a Worcester boiler that you have? Pictures would be good though.

 

[townfanjon]

Is it a Worcester boiler that you have? Pictures would be good though.

Would rather look at a pic of a nice burd than a Worcester

 

[Chuck]

Also wondered about how much it would cost to have a new 22mm pipe fitted in place if the 15mm? It'seems about 2 meters long with 1 bend and will probably need a couple of elbows.

It'll cost nothing to leave it alone, which is what you should do IMO. When your boiler is next replaced (they don't last forever) the installer will upgrade the run if necessary as part of the deal and it will add about £15 to the total cost.

As an isolated job, with call-out fee, performing necessary tests and a 'small job premium' expect to spend ten times that.

 

[Harvest Fields]

It'll cost nothing to leave it alone, which is what you should do IMO. When your boiler is next replaced (they don't last forever) the installer will upgrade the run if necessary as part of the deal and it will add about £15 to the total cost.

As an isolated job, with call-out fee, performing necessary tests and a 'small job premium' expect to spend ten times that.

If the gas pipe should have been 22mm then it should have been done on the last boiler install. If the last Engineer didn’t do it. What makes you think the next will?

 

[Last Plumber]

If working Pressure at the Boiler is as it's supposed to be, there's no issue with what size it is.

 

[Harvest Fields]

If working Pressure at the Boiler is as it's supposed to be, there's no issue with what size it is.

Unless the manufactures instructions say it should be a certain size, which they all do.
Prime example of engineers being lazy and cutting corners

 

[Last Plumber]

Unless the manufactures instructions say it should be a certain size, which they all do.

You're quite right there Harvest, they do tell you not to use pipe work below the size of the connection to the appliance.

This is from Vaillant:-

2.5.3 Gas supply An existing gas meter should be checked to ensure that it is capable of passing the rate of gas supply required. Installation pipes should be fitted in accordance with BS 6891, in IE in accordance with the current issue of IS 813. 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. The complete installation must be tested and purged in accordance with: – IGE/UP /1B for systems up to 0.035 m3 capacity – for larger systems IGE/UP/1A and – for LPG installations refer to BS 5482 - 1 or – IGE/UP1 Edition 2 for larger volume installations.

This is from BS 6891 Which Vaillant refer to:-

5.2 Pipe sizing 5.2.1 When designing an installation, the sizes of all installation pipes shall be determined from the maximum gas rate of the appliances to be connected. COMMENTARY AND RECOMMENDATIONS ON 5.2.1 Allowance should also be made for any future extensions which might be anticipated, especially if the pipes are to be buried. Annex A gives a method of calculating pipe sizes in a system. 5.2.2 The pressure drop between the outlet of the meter and the points to be connected shall not exceed 1 mbar at maximum flow conditions (see Table 1).

If the connection on the appliance is 15mm, it is fine to use 15mm pipe as long as it provides the correct volume of gas and an acceptable pressure drop across the installation, with all the other necessary considerations taken into account.

 

[DIYer]

Thanks for the replies, i've added a couple of photos to hopefully shed a bit more light on the matter

The boiler is a glowworm combi

 

[Harvest Fields]

That pipework looks a right mess. But it does look like the connector onto the boiler is 15mm which means it is ok. When yor gas Engineer changes the pipework and makes it neater. I would extend the 22mm gas pipe almost right up to the boiler. But thats just me.

 

[Last Plumber]

Crikey maud!

A Man could throw copper tube and get it to land neater than that!

Sorry, I know my feelings on neat work are irrelevant but sometimes you just have to comment.

 

[Scott_D]

Are you fitting a new kitchen around the boiler?

 

[Harvest Fields]

Are you fitting a new kitchen around the boiler?

If you are I would put a new boiler in now. Whilst it is all out.

 

[Jim Goodenough]

Thanks for the replies, i've added a couple of photos to hopefully shed a bit more light on the matter

The boiler is a glowworm combi View attachment 33006 View attachment 33007

You need to check out the corrosion on that 22mm gas pipe below floor level!

 

[jtsplumbing]

You need to think about getting rid of the Lead pipes as well

 

[Jim Goodenough]

Yep - one of those lead pipes looks like a hot service to somewhere?, you'll be losing a lot of heat in the lead and to the ground where it's covered in soil 😱

 

[Scott_D]

If you are I would put a new boiler in now. Whilst it is all out.

Agreed
New boiler and replumb while the floor is up. Spend some money now rather than later

 

[Chuck]

If the gas pipe should have been 22mm then it should have been done on the last boiler install. If the last Engineer didn’t do it. What makes you think the next will?

I don't, which is why I qualified it with the phrase "if necessary". It could become necessary because (a) different model of boiler with differing MIs from the current one, or (b) change in regs, etc.