New 30kw+ combi gas supply pipe -quotes are conflicting

[Spoonyboy]

Hi, Hope someone can spare a minute and give me an opinion.

I'm looking to replace my standard Glowworm CH system with a new 30kw+ Combination boiler & have had 4 quotes so far. They seem to be conflicting and I wanted a second opinion.

The new boiler will be installed in the same place as the old one which is 2-3meters away from gas meter outside. There is a 15mm gas supply to the current boiler, 2 of the installers have said this is fine and won't need to change. The other 2 (including BG) have said a new 22 or 28mm supply pipe will need to be run from gas meter to boiler??

The current gas pipe runs inside the cavity wall between the study and utility (where boiler is) and I don't really want a new gas pipe running up the outside of the house next to the back door. Would it be possible to run a new 22mm gas pipe in the cavity wall where the existing pipe already is? (mess to interior walls can be easily fixed)

The BG quote was £3360 which is not too bad TBH (or am I being taken for a ride?)
- British Gas 532 boiler (WB 30cdi?) or British Gas 537 for extra £100
- powerflush & magnaclean filter
- wireless rf control
- old boiler, HW cylinder, cold water tank removed
- 1 years Homecare

One other quote was £2600 for the same work with an Alpha cd35c boiler (cheshire).

Any comments or advise is really appreciated.

Cheers

 

[kevplumb]

you are not allowed to run a gas pipe in a cavity

 

[scape279]

I'm having exactly the same trouble as the OP.

I've been getting quotes to replace my old heating system (one with a HW cylinder) with a condensing combi etc.

Generally, there seems to be conflicting advice regarding gas pipe size: from the limited research I have done, the quotes I've got so far and other heating engineers I have spoken to.

We currently have a 22mm supply that runs the entire length of the house (mid terrace) which Ts off to 15mm to the current boiler and 15mm to the cooker. 2 quotes so far have said the 22mm will be fine. A different heating engineer said it would need to be 28mm.

I even found a gas pipe size chart and did the calculations myself knowing nothing about gas. The results came to 28mm to the first T as most modern boilers seem to use around 3m3/hr of gas when on full whack.... 22mm over a 20m run (including taking into account bends etc) allows max 2.9m3/hr so the boiler would be under gassed without even entertaining the cooker!

So what is right? What is wrong? Have I got it right or wrong? Why does gas pipe sizing seem to be such a grey area amongst engineers? Surely its mathematically right or wrong.

Help

 

[ServiceNumpty]

You have answered your own question as to gas pipe sizing, so which installer now looks favourable.

 

[lawrance]

Hi, Hope someone can spare a minute and give me an opinion.

I'm looking to replace my standard Glowworm CH system with a new 30kw+ Combination boiler & have had 4 quotes so far. They seem to be conflicting and I wanted a second opinion.

The new boiler will be installed in the same place as the old one which is 2-3meters away from gas meter outside. There is a 15mm gas supply to the current boiler, 2 of the installers have said this is fine and won't need to change. The other 2 (including BG) have said a new 22 or 28mm supply pipe will need to be run from gas meter to boiler??

The current gas pipe runs inside the cavity wall between the study and utility (where boiler is) and I don't really want a new gas pipe running up the outside of the house next to the back door. Would it be possible to run a new 22mm gas pipe in the cavity wall where the existing pipe already is? (mess to interior walls can be easily fixed)

The BG quote was £3360 which is not too bad TBH (or am I being taken for a ride?)
- British Gas 532 boiler (WB 30cdi?) or British Gas 537 for extra £100
- powerflush & magnaclean filter
- wireless rf control
- old boiler, HW cylinder, cold water tank removed
- 1 years Homecare

One other quote was £2600 for the same work with an Alpha cd35c boiler (cheshire).

Any comments or advise is really appreciated.

Cheers

Keep in ming with the bg quote. It is highly unlikely a direct employee will carry out the work. It is highly likely that a cheap sub contractor will carry out the work and for what they get out of it they will almost certainly cut corners and the end result being a poor job.

 

[Spoonyboy]

Hi, Hope someone can spare a minute and give me an opinion.

I'm looking to replace my standard Glowworm CH system with a new 30kw+ Combination boiler & have had 4 quotes so far. They seem to be conflicting and I wanted a second opinion.

The new boiler will be installed in the same place as the old one which is 2-3meters away from gas meter outside. There is a 15mm gas supply to the current boiler, 2 of the installers have said this is fine and won't need to change. The other 2 (including BG) have said a new 22 or 28mm supply pipe will need to be run from gas meter to boiler??

The current gas pipe runs inside the cavity wall between the study and utility (where boiler is) and I don't really want a new gas pipe running up the outside of the house next to the back door. Would it be possible to run a new 22mm gas pipe in the cavity wall where the existing pipe already is? (mess to interior walls can be easily fixed)

The BG quote was £3360 which is not too bad TBH (or am I being taken for a ride?)
- British Gas 532 boiler (WB 30cdi?) or British Gas 537 for extra £100
- powerflush & magnaclean filter
- wireless rf control
- old boiler, HW cylinder, cold water tank removed
- 1 years Homecare

One other quote was £2600 for the same work with an Alpha cd35c boiler (cheshire).

Any comments or advise is really appreciated.

Cheers

Keep in ming with the bg quote. It is highly unlikely a direct employee will carry out the work. It is highly likely that a cheap sub contractor will carry out the work and for what they get out of it they will almost certainly cut corners and the end result being a poor job.

eh? Is this right? So I pay a higher price just to get the WB badge on the boiler changed to a BG one? I thought they would be british gas engineers and therefore not need to cut any corners!?

 

[scape279]

You have answered your own question as to gas pipe sizing, so which installer now looks favourable.

The irony is, the engineer that has given the correct advice is 250 miles away from my house and no longer gas safe registered.

 

[Razor900]

Keep in ming with the bg quote. It is highly unlikely a direct employee will carry out the work. It is highly likely that a cheap sub contractor will carry out the work and for what they get out of it they will almost certainly cut corners and the end result being a poor job.

Another load of Shiite being spouted on here

Why would a subbie do a worse job than direct labour? One bad job and they are out!

Oh and by the way there's a subbie in Northamptonshire that has the highest customer satisfaction score on the patch for installs pi55ing all over direct labour

 

[simond]

I lose a few jobs by insisting that the gas supply is within the limits set out by Gas Safe and British Standards. There are always installers prepared to undersize the supply, worryingly many don't understand how to calculate it.

It is quite refreshing to see a customer who is prepared to see through their ignorance. Shame there aren't more like you.

Should add that there are plenty of reputable installers out there, you have been a bit unlucky.

 

[lawrance]

Keep in ming with the bg quote. It is highly unlikely a direct employee will carry out the work. It is highly likely that a cheap sub contractor will carry out the work and for what they get out of it they will almost certainly cut corners and the end result being a poor job.

Another load of s**** being spouted on here

Why would a subbie do a worse job than direct labour? One bad job and they are out!

Oh and by the way there's a subbie in Northamptonshire that has the highest customer satisfaction score on the patch for installs p******g all over direct labour

yeah yeah

 

[Agile]

Some of my colleagues complain that I have a low opinion of many installers.

This is yet another example of how a customer, with a little diligence on the web, can calculate the size of gas pipe needed and demonstrate that half of his quotes by gas trained people show themselves up as muppets!

 

[kevplumb]

Some of my colleagues complain that I have a low opinion of many installers.

you should try it

then you can form an opinion