Significant drop in gas pressure between meter and boiler

[CMairiD]

With regards to WB appliances, it is worth looking at TB 115 & http://www.worcester-bosch.co.uk/cache/file/20/minimum-gas-operating-pressure.pdf

 

[Agile]

I dont see how any manufacturer can tell you how to opt our of a British Standard !

Whilst they may be happy as far as their boiler(s) are concerned that will not make your inadequate gas suppy meet the BS requirements.

Gas Safe use the BS and will rate you accordingly.

Since the customer always has to pay I dont see why so many RGIs want to do a bad job.

Tony

 

[MatthewHurt]

Each elbow is approximatley 0.5 Meters worth of pipework in terms of pressure loss on a gas instillation (so 22 elbows is adding an effective length of 11 Meters to the pipe run between your meter and boiler)
You should aim to lose no more than 1Mb worth of pressure accross the whole of the instillation (the furthest appliance I.E your Boiler should be running at 20Mb)
It sounds as if your current Meter - Aplliance pipe run is very badly done and needs replacing, Normaly I would guess it needs to be in 28 mm Copper all the way up untill it elbows up to the boiler (at which point it will need to be in 22mm)
The instillation should also be as straight as is possible

 

[Blackcatgas]

The gas valve on the Worcester is restrictive and you can lose 2mb across it on the test nipple, if you were to put in a test nipple on the 22mm pipe just before it goes into the boiler then you would most likely get a different reading.
Anyway lets say you commision a boiler at 3pm on a tuesday in the summer you might get the "correct" reading, then try commisioning the same boiler at peak demand time during one of the winters weve just had then you might not get it.

 

[SPC]

Each elbow is approximatley 0.5 Meters worth of pipework in terms of pressure loss on a gas instillation (so 22 elbows is adding an effective length of 11 Meters to the pipe run between your meter and boiler)
You should aim to lose no more than 1Mb worth of pressure accross the whole of the instillation (the furthest appliance I.E your Boiler should be running at 20Mb)
It sounds as if your current Meter - Aplliance pipe run is very badly done and needs replacing, Normaly I would guess it needs to be in 28 mm Copper all the way up untill it elbows up to the boiler (at which point it will need to be in 22mm)
The instillation should also be as straight as is possible

This is true, i've been there and worked it out. theres also an 11kw hob/oven approx 1/3 down the line. the 28mm needs to be ran to within 5m of the boiler to conform to BS.

 

[bob the plumber]

can you actually lose your gas safe for undersizing a gas pipe to an appliance? ive never known it?? though i wish it was the case as for instances like this the installer has obviously knocked 100's of pounds off his price compared to an engineer pricing it to do it right and taken a short cut and left the customer with a poor un-efficent install

 

[donkeeboy]

Im the OP. Sounds to me that there is not any way possible to get this done, on the basis of what I have read above, and comply with the regs at the same time.

The gas pipe has to go a fair way, and there is NO direct route. Sure we can cut down on the 22 elbows a bit ,but only a few. It just is not possible.

Whats the deal with situations like these? Is there any flexibility? There are physically too many obstructions, and there isnt even a closer place to relocate the boiler to.

One way to reduce elbows that's been suggested would be to run gas pipe low down accorss a door step that exists. As opposed to up and over the door. Now I'm no gas-safe expert but that seems counter-produuctive to me - the gas pipe is there in a place where its liable to get damaaged by accident - namely the next time I get a new fridge or cooker and lugging it thru the door.

Do the regs say its better to have a high pressure at a cost of putting gas pipes in places where they are in prime position to be subject to damage, or sacrifice an amount of pressure and put the gas pipes up the wall where they cannot be damaged?

This is all quite frustrating, it seems there is no easy way to solve a problem which does not even cause a problem except in the regulations. There is no prob in the running of the 40.8kw boiler and gas hob (elec oven) at full whack in the 3 years i had it.

In fact,, for the 10 years prior to that I had 48.5kw boiler + gas hob + double gas ovens. No problems.

I want it to comply with the regs, but it does not seems possible 🙁

 

[SPC]

theres no problem with running the 28mm supply all the way going the same route as it is at the moment, its just costly in materials and labour. if a gas pipe is suseptable to damage then it needs to be suitably protected. There is no flexibility. Boiler relocation would be ridiculous when in reality it needs a day of a RGSE and a bundle of 28mm pipe.