Ideal Boilers 14mb inlet pressure

[Matt0029]

It says in the manufactures instructions that a 24kw ideal boiler will work ok with a gas inlet pressure of 14mb or more. With a working pressure at the meter of 19-23mb this will be far greater than the allowed 1mb drop for the pipework. They allow 1.5mb drop for the gas valve too. If installed with a 14mb inlet pressure it isn't to gas safe regs. I ask as I have looked at a job where there is around 5-6meters including bends of 15mm copper from the meter that goes in a sold floor chase and up to the old non-condensing boiler. A 24kw boiler needs 2.28m3/h of gas the current pipework will supply around 1.9m3/h. To take the supply up to 22mm would be a huge job with a lot of disruption. Would the 15mm pipe likely be ok in this situation? Another note there is no other gas appliances in the building.

 

[ShaunCorbs]

Is it effecting combustion and any other appliance?

 

[Scott_D]

If its a new install then it has to be right

 

[Matt0029]

Is it effecting combustion and any other appliance?

The boiler that is in is broke. Needs a new pcb. Not worth repairing due to age of boiler.
[automerge]1569182312[/automerge]

Is it effecting combustion and any other appliance?

There's only a gas boiler fire and hob are electric.

 

[ShaunCorbs]

Need to up the main of fitting a new boiler sorry to say

 

[EvilDrPorkChop]

Last time Gas Safe visited me they say follow the Manufactures instructions, we were looking at Vaillant's we'd installed and he was saying that they are quite good allowing a range of 13-17mb at Gas Valve inlet. He didn't seem concerned about the 1 mbar drop across the installation.

 

[Scott_D]

Last time Gas Safe visited me they say follow the Manufactures instructions, we were looking at Vaillant's we'd installed and he was saying that they are quite good allowing a range of 13-17mb at Gas Valve inlet. He didn't seem concerned about the 1 mbar drop across the installation.

Vaillant dont list a drop through the gas valve/ boiler pipework though.
Ideal say 1.5 lost at the gas valve test point
So minimum should be 2.5 less than at the meter

It can work down to 14mb if you could only achieve 16.5 at the meter

 

[Matt0029]

Need to up the main of fitting a new boiler sorry to say

Needs up sizing to 22mm?

 

[ShaunCorbs]

Needs up sizing to 22mm?

Yes depending on route and length

 

[Matt0029]

That's the pipe coming out of tree floor screed. Doesn't look in too good nick.

 

[firemant]

Why are we even discussing this? You CANNOT do work that does not meet the standards. The standard is a max 1mb drop between the meter and immediately before the appliance. Obviously there will be a further drop across the appliance valve, which is permissible. The MIs DO NOT say you can install to 14mb at the boiler. It says the boiler will work at 14mb. So if you go to one fitted by a lazy cowboy, you are permitted to leave it in service if it is at least that minimum.

If you fit a boiler with, say, a 6mb drop, the boiler will probably be okay. But what happens when the grid pressure fluctuations kick in, and the 21mb at the meter suddenly drops to 17mb. Which is not unusual in some locations. Suddenly, your bodged install is now running at 11mb at the boiler, with the inherent safety issues.