Gas Inlet Working Pressure in Vaillant 630 system boiler

[Agile]

Very few manufacturers will say that on installation their boilers MUST be checked with a FGA. I would be very surprised if Vaillant really say its a must. In any case hardly 1 in 10 installers even own an FGA. Even those who do rarely use them and many dont even know confidently how to interpret the reading they obtain.

The boiler will happily work with your gas supply but the fact remains that it does not comply with the British Standard for pipe sizing. A complaint to CORGI would result in a defects notice being served on the installer to upgrade the pipe at his cost!

We would charge about £135 to upgrade the pipe in your garage to 28 mm ( with us retaining the 22 mm ! ). That would probably result in the presure at the inlet to the boile being about right with a loss of 1 mB in the pipework from meter to boiler.

The problem with those Vaillant boilers is that they have an inlet pressure test point on the gas valve but a restricted convoluted pipe which loses a few mB extra. That can cause some installers difficulties with their CORGI inspectors who dont really understand the situation. At least one has had to fit a test point on the inlet to the boiler to show the inspector that its adequate at that point.

Tony Glazier

 

[hughs]

One part I forgot to answer was whether he used flue gas analysis to set up the system. If this means measuring the flue gas, then I do not think so (although I may be wrong). He measured the gas pressure at the meter and boiler and the flow of gas at both ends. Hope this helps.

You can't commission an Ecotec without an FGA.

As said the boiler won't be hurt, but it just points to a sloppy job that doesn't comply with current regulations.

If the boiler has been set up for 9.0% CO2 then it is working correctly.

Thank you Dave.

Is there any way I can find out if the boiler has been set up for 9.0% CO2?

Any thoughts on costs to replace say 9 metres of 28mm pipe?

 

[Agile]

We would charge about £135 to upgrade the pipe in your garage to 28 mm ( with us retaining the 22 mm ! ). That would probably result in the pressure at the inlet to the boiler being about right with a loss of 1 mB in the pipework from meter to boiler.

Tony Glazier

There is no way that anyone can tell if the installer ever checked the boiler with an FGA unless he left any evidence that he had done it. I assume that he did not fill in the Benchmark. I think its safe to say that he did not use an FGA !

If the Benchmark is not completed then CORGI say that the boiler has not been commissioned and is At Risk and should not be used until it has been commissioned!

I am not yet convinced that Vaillant actually say that their boilers MUST be FGA checked before putting them into service. Most manufacturers dont ! They immagine saying that limits their sales to the 10% of installers who actually have an FGA instrument and know how to use it.

Tony

 

[Deleted member 105431]

We would charge about £135 to upgrade the pipe in your garage to 28 mm ( with us retaining the 22 mm ! ). That would probably result in the pressure at the inlet to the boiler being about right with a loss of 1 mB in the pipework from meter to boiler.

Tony Glazier

There is no way that anyone can tell if the installer ever checked the boiler with an FGA unless he left any evidence that he had done it. I assume that he did not fill in the Benchmark. I think its safe to say that he did not use an FGA !

If the Benchmark is not completed then CORGI say that the boiler has not been commissioned and is At Risk and should not be used until it has been commissioned!

I am not yet convinced that Vaillant actually say that their boilers MUST be FGA checked before putting them into service. Most manufacturers dont ! They immagine saying that limits their sales to the 10% of installers who actually have an FGA instrument and know how to use it.

Tony

Vaillant state the boiler is factory set for a supply of 20mb. You must gas rate the boiler after fitting and check inlet pressure but a fga is not essential (although any good installer would).

 

[Agile]

Thats what I expected !

Interesting question about the supply pressure!

I wonder if thats 20 mm at the pipe connection to the boiler or at the gas valve test point.

Its a great pity that there is so much confusion and misunderstanding of these matters!

I met a CORGI inspector who totally misunderstood how to measure the pipe pressure loss. He thought you measure the pressure at the meter with three gas rings on and then measured the pressure at the boiler on full power!

Tony

 

[Deleted member 105431]

Thats what I expected !

Interesting question about the supply pressure!

I wonder if thats 20 mm at the pipe connection to the boiler or at the gas valve test point.
Its a great pity that there is so much confusion and misunderstanding of these matters!

I met a CORGI inspector who totally misunderstood how to measure the pipe pressure loss. He thought you measure the pressure at the meter with three gas rings on and then measured the pressure at the boiler on full power!

Tony

20mb to the gas cock of boiler. (although there is no test point there, only on gas valve)