How do I know if there's a 20mm incoming gas main?

[AssuredHeating]

Ok, so today it's seems I've made a massive cock up. A while back a client asked me to recommend a combination boiler for installation.
I recommended a Worcester 34cdi, that seemed to be suitable for his property, 30kw CH, 34kw HW, however the client had loads of cold water flow so I said he could also go with the 38CDi for a better HW flow rate.
The 38CDi was installed, nice easy job, came to commissioning put the boiler at full rate, and got 10mbar working pressure at the meter. I got straight on the phone to Transco to check the governor, they came round saying it needed a bigger supply pipe as it's only 20mm. I thought no matter what boiler I put in, they have to give me atleast 19mbar working pressure, it turns out I'm wrong.
The clients have recently had this 20mm installed, and apparently the 20mm was specified by National Grid as that would provide enough pressure for the existing system.....So I should of checked the 20mm pipe and put a same rate boiler back in.
People these days require more and more HW flow rates for a better shower, boiler manufacturers are making bigger boilers to meet the need, why are Transco not future proofing their installations by simply installing a 25mm pipe!
I can't be the only installer not to check the incoming mains pressure at the quotation stage?.

 

[Killy Bing]

Are they rural? Fed from their own meter pit?

medium pressure would sort it but i wouldent know to go about sorting it.

what's the pressure service side?

 

[AssuredHeating]

Are they rural? Fed from their own meter pit?

medium pressure would sort it but i wouldent know to go about sorting it.

what's the pressure service side?

Hello, thanks for your reply.

its a well built up area.

The latest is National grid are going to move the gas meter to the front of house to make the 20mm underground a shorter distance, then they will run 35mm copper from the meter to the loft, 28 across the loft then 22 into the boiler, it's going to look terrible! And they say they may not even get enough pressure at the governor then. We have to do simple pipe sizing calculations for our internal pipe work, how come they can't do a pressure loss calculation from the road to the governor???

 

[E4gas]

Are you gas safe !

 

[AssuredHeating]

Of course I'm Gas Safe

 

[Billy Bob Bob]

the utilities are coping out,they have to provide min 19mb this is fact,i have had them run new lines before when they have run plastic up the old metal pipework

 

[Billy Bob Bob]

Are you gas safe !

he sounds like he is to me and i think transco are taking the proverbial

 

[AssuredHeating]

My replays don't seem to be showing......

 

[E4gas]

Ive had yellow filings from transco blocking the incoming ECV , it's when they tap in to the main ,

 

[Ermintrude]

Yeh we get few of poor insertion jobs where pressure is pap. But usually it's water or guff in mains. Where is that Jefaz he should be able to provide answers as he's employed by trannys. Notice how I didn't say he worked for them!

 

[Reltub]

I was talking to a nat grid engineer the other day and he said the min they have to supply is something like 16mb!

 

[quality]

the utilities are coping out,they have to provide min 19mb this is fact,i have had them run new lines before when they have run plastic up the old metal pipework

I had this at my house a couple of years ago

 

[albatross]

On the CDi's it is possible to downrate the output. Ring Worcester tech. This may give you a solution or at least help temporarily.

Alternatively how about an unvented cyl and change to a system boiler (or use combi as a system boiler and downrate) to whatever is needed, say 12/15/18/24 kw.

 

[acecharly]

I was talking to a nat grid engineer the other day and he said the min they have to supply is something like 16mb!

How can you make appliance working pressure if this is the case?

 

[jase158]

U can downrate central heating but not hot water side!!

 

[acecharly]

Exactly so i cant see how they could safely do that.

When they line gas pipes dont they just ramp up the pressure a bit to make sure this doesnt happen?

You would think reducing the size of a main was a bit crazy, demands hardly likely to go down. Its probably just down to cost id say.

 

[wattsie1987]

I have loads of experience with this and have had as low as 16mm inserted at ECV's I'v had loads of debates regarding this and have has them renew services in 32mm to the ECV. Ultimately your customer is paying a set standing charge on a set meter size I'm guessing E/U6. So it is the duty of the gas supplier to have a service pipe to the meter capable of supplying the flow rate to the badge capacity of the meter in this case 6m3/h. Its as simple as that.

 

[AssuredHeating]

Ok, so the latest update is National Grid have installed the meter at the front of the house, thus making the 20mm run shorter, then they've run the 35mm copper pipe over to my boiler, apparently the pressure is good now..... I'm going there tomorrow to complete the benchmark, what a pal-lava.
So does anyone have any answers if it's not visible? The last thing I want to do is install another powerful boiler that the client can't use for a week!
I'm aware by quickly wacking on the ecv I can get the road pressure, but not working pressure.....

 

[wattsie1987]

I've got a fitting that goes between the ECV and anaconda with a test point on so i can take a working pressure at the ECV. Not massively beneficial if you are considerably upgrading the demand on the supply but will give a rough idea with the existing appliances running.

 

[AssuredHeating]

I did speak to Worcester, and it is possible to down rate the kW rating on HW and CH which is quite cleaver, however this would invalidate the warranty if those setting were kept long term.
Thanks for all the replies.

 

[AWheating]

I was talking to a nat grid engineer the other day and he said the min they have to supply is something like 16mb!

This is correct as they can allow as low as 16mb at "peak demand". What they tend to fail to tell you is that this peak time is only supposed to be something like 5% of the day. So unless it's early morning or tea time they can't really argue this, although some engineers will use this figure to avoid doing anything for you.

 

[AssuredHeating]

Went back there today, I now have 19mbar working pressure on 38kw full rate. So all is finally good. Thier pipe work from the meter to the boiler was terrible though......cocks.