Low gas pressure

[jaydebruyne]

Slow reacting regulator when the boiler fires up?

Still getting same pressure loss after 10 mins on max rate

 

[jaydebruyne]

sorry but i disagree the hob wouldnt be going out due to 1 mbar, also ive never found anything near what mis say for gas valve restriction normally around 0.5-1 mbar

Worcesters are pretty spot on at 1.5 loss from ISO to valve, plus the 1 from meter to boiler..

 

[wattsie1987]

sorry but i disagree the hob wouldnt be going out due to 1 mbar, also ive never found anything near what mis say for gas valve restriction normally around 0.5-1 mbar

To be honest I've never had 3.5 but have had 2 or so. Your right about cooker too I've had cookers lower than 15 not go out. Sounds like blockage to me and possibly more than 1.

 

[jaydebruyne]

sorry but i disagree the hob wouldnt be going out due to 1 mbar, also ive never found anything near what mis say for gas valve restriction normally around 0.5-1 mbar

Shaun would you reckon blasting it with a compressor is worth doing? I think the guy doesn't want pipework going around his house

 

[Scott_D]

Still getting same pressure loss after 10 mins on max rate

But if it's slow to react, when the boiler fires up the WP at the meter drops for a second and the Hob goes out

 

[ShaunCorbs]

Shaun would you reckon blasting it with a compressor is worth doing? I think the guy doesn't want pipework going around his house

I would install a test nipple below boiler least you know then if it's the boiler or Pipework

 

[ShaunCorbs]

But if it's slow to react, when the boiler fires up the WP at the meter drops for a second and the Hob goes out

Think it's steady and not just on start up

 

[jaydebruyne]

But if it's slow to react, when the boiler fires up the WP at the meter drops for a second and the Hob goes out

The hob only goes out on simmer.

 

[jaydebruyne]

But if it's slow to react, when the boiler fires up the WP at the meter drops for a second and the Hob goes out

The hob only goes out on simmer.

 

[Leo21]

The hob only goes out on simmer.

That special soumds like a dicky hob. Cut a test nipple just underneath the ISO and re test.

 

[Leo21]

The hob only goes out on simmer.

That special soumds like a dicky hob. Cut a test nipple just underneath the ISO and re test.

 

[jaydebruyne]

That special soumds like a dicky hob. Cut a test nipple just underneath the ISO and re test.

I've ID'd the hob. But still getting 5.5mb drop from meter to boiler inlet after disconnecting the hob from the supply. To be honest I'm not really worried about the hob, they can just buy a new one. But I need to sort the pressure issue.

So it's either try and clear the blockage, if there is one, or do a complete new run.

Just toying wether to get a compressor to blow out any blockages :/

 

[jaydebruyne]

Vaillant reckons the boiler needs 28mm from the meter... gonna calculate it properly when I get home as forgotten how to do it :/

 

[ShaunCorbs]

Vaillant reckons the boiler needs 28mm from the meter... gonna calculate it properly when I get home as forgotten how to do it :/

What's your total length and how many elbows ?

 

[jaydebruyne]

Let's say 6m, accessible elbows = 10

 

[ShaunCorbs]

22 more than good enough pressure drop of 0.73 aprox

At 32kw 8m 12 elbows

 

[jaydebruyne]

Oooh is that an app?? What is the app called?

 

[jaydebruyne]

Don't forget the 7kw net hob

 

[ShaunCorbs]

Don't forget the 7kw net hob

Allowed 5kw as most I find are about that can do you one for 40kw to be sure

 

[Riley]

What Are you distances again mate

 

[ShaunCorbs]

What Are you distances again mate

8m and 10 elbows mate

 

[jaydebruyne]

Allowed 5kw as most I find are about that can do you one for 40kw to be sure

View attachment 28762

What app is that Shaun?

 

[ShaunCorbs]

What app is that Shaun?

Mr combi pipe calc / gas calc

 

[ShaunCorbs]

What app is that Shaun?

Mr combi pipe calc / gas calc

 

[Riley]

22 more than good enough pressure drop of 0.73 aprox

At 32kw 8m 12 elbows

View attachment 28761

Exactly what I used

 

[Riley]

22 more than good enough pressure drop of 0.73 aprox

At 32kw 8m 12 elbows

View attachment 28761

Exactly what I used

 

[ShaunCorbs]

Up the pipe work jay easily accessible part

Would of thought it would be fine but if manufacturer said needs bigger up it

 

[Riley]

Seems silly though when the simple calculation tells you that the 22 should be fine

 

[jaydebruyne]

Up the pipe work jay easily accessible part

Would of thought it would be fine but if manufacturer said needs bigger up it

Yeah, I'll do 28mm outside and see if that helps. Cheers Shaun! Cheers Riley

 

[ShaunCorbs]

Seems silly though when the simple calculation tells you that the 22 should be fine

Yep but are they going to refuse warrenty if somthing wrong later down the line. Saying aload of bumf about Pipework

 

[Riley]

It should sort it but I'm still not entirely convinced that it should be required

 

[Riley]

Totally agree Shaun it just seems daft when we are all using one type of calculation and then the manufacturer tells you you need to up size it. If there is a factor to take into account with their product then they should make you aware of this otherwise quite legitimately you are going to do your pipe sizing calculation and only find out when the thing is connected that it doesn't work. It hardly seems fair for them to refuse the warranty when you have actually done the due diligence of calculating the pipe sizes

 

[ShaunCorbs]

Any update jay ?

 

[jaydebruyne]

Actually, as per the Viper book, I calculated the pipe size required to carry 3.75m3/h and its 28mm :/ it's because the pipework from the meter doesn't branch until it hits the boiler when it tees to the hob. I just hope that the section I up to 28mm is enough.

 

[jaydebruyne]

Any update jay ?

Going to do the job Sunday Shaun, will let you know as soon as I'm done.. fingers crossed. I'm not 100% convinced it's going to work as only upping half the run but we'll see!