Huge gas pressure drop between meter and boiler. Help!

[Harry Bloomfield]

Yet your benchmark pic is blank ?

It says 'OR'. Suggesting 'Burner operating pressure' OR 'Burner input pressure'. Later item is indicated to be 20mbar for both HW and CH.

 

[BlueLoo]

System boiler, so unless its been fitted with vaillant controls which I imagine its not, then you need the higher flow temp for DHW production. Had it had vaillant controls then you could select independent flow temps for heating and then higher one for DHW (or even lower for DHW and weekly legionella cycle)

ABV not required by this boiler, so wont have any real effect on it.

So no point in this boiler being condensing?

Is that not a gross install error and against best practice?

If not, is it not also "a good idea" to get proper controls so that it does condensing?

 

[ScottishGasMan]

So no point in this boiler being condensing?

Is that not a gross install error and against best practice?

If not, is it not also "a good idea" to get proper controls so that it does condensing?

Of course it's far better to control any system pretty much with weather compensation and priority DHW, but that comes at a cost itself, its still not widely understood by many in the industry so not promoted by your average Joe.

In the UK the industry falls far behind some other countries in terms of quality of installs but also quality of customers, most folk will not part with a penny more than they can get away with when it comes to their heating but wi blow silly amounts on cars and kitchens. So even the guys who do spec higher quality installs face a never ending uphill battle of educating customers and justifying their higher costs

 

[ScottishGasMan]

In a previous life as a warranty engineer I mainly visited new (<5 year old) systems, and can easily say 95% were left set at fixed 75⁰c CH flow.

 

[ianmcd]

It says 'OR'. Suggesting 'Burner operating pressure' OR 'Burner input pressure'. Later item is indicated to be 20mbar for both HW and CH.

Harry it does not say "burner input pressure" appliance inlet working pressure and burner pressures are completely different

 

[BlueLoo]

In a previous life as a warranty engineer I mainly visited new (<5 year old) systems, and can easily say 95% were left set at fixed 75⁰c CH flow.

It's law in the UK to only sell condensing boilers no?
Must also be law that they are installed with appropriate controls to ensure they operate in condensing mode else what is the point? Lol.

Wait, they are more expensive and complex than non condensing so....

In my work, I'm forever telling younger engineer's that codes only do so much...

 

[ScottishGasMan]

Must also be law that they are installed with appropriate controls to ensure they operate in condensing mode

But its not.

Manufacturers are only allowed to sell condensing boilers. But there is zero laws that state they need to be fitted to condense.

Unfortunately that's the govt for you.

 

[Harry Bloomfield]

Harry it does not say "burner input pressure" appliance inlet working pressure and burner pressures are completely different

Sorry, yes - Gas inlet pressure.

 

[Deleted member 267285]

It's law in the UK to only sell condensing boilers no?
Must also be law that they are installed with appropriate controls to ensure they operate in condensing mode else what is the point? Lol.

• Yes, only condensing boilers allowed to be sold
• Boiler plus is the minimum standard along with boiler interlock - not sure if regulated that well, if at all
• Best will in the world, could be setup correctly, customer not happy as rads don’t make them have red hands after touching, become google warriors, or ask on forums, like DIYnot.com how to increase their temperatures etc.

 

[ScottishGasMan]

Condensing boilers are still more efficient than their Std eff counterparts, even when there not condensing. Enough that there was a notable drop in domestic gas use after the introduction of condensing only boilers. But that could be a further 5-10% had they legislated that they must be on lower temperature systems

 

[ScottishGasMan]

• Yes, only condensing boilers allowed to be sold
• Boiler plus is the minimum standard along with boiler interlock - not sure if regulated that well, if at all
• Best will in the world, could be setup correctly, customer not happy as rads don’t make them have red hands after touching, become google warriors, or ask on forums, like DIYnot.com how to increase their temperatures etc.

Unfortunately boiler plus was hijacked by controls manufacturers and diluted down to be essentially meaningless

 

[fixitflav]

It doesn't.

I just meant that if he was replacing like for like, he might argue that as the previous set-up was OK, and the gas flow hadn't changed, there was no need to check the gas pipe.

 

[Harry Bloomfield]

Condensing boilers are still more efficient than their Std eff counterparts, even when there not condensing. Enough that there was a notable drop in domestic gas use after the introduction of condensing only boilers. But that could be a further 5-10% had they legislated that they must be on lower temperature systems

With better controls.

 

[fixitflav]

Silly question, why would you think that?

Mainly because of the high boiler output, much higher than a typical house needs. But of course it might be a huge house.

 

[BlueLoo]

Condensing boilers are still more efficient than their Std eff counterparts, even when there not condensing. Enough that there was a notable drop in domestic gas use after the introduction of condensing only boilers. But that could be a further 5-10% had they legislated that they must be on lower temperature systems

A 10% saving on current/future gas bills can be big money.
Perhaps something for the OP to add to the shopping list.

Thanks for the replies. Interesting stuff.