Gas size

[Polishicebreaker]

Yes that's fair enough, I've obtained as much info as I can and probably do have everything but I confess I don't have the skill/method to do the equation.

Here's a question though; if you have to reduce whatever pipe that goes in to 10mm as that's the only bubble tester available, wouldn't that defeat the object of using larger pipe after that point in the system?

[Murflynn]

no. a short length of reduced size affects the pressure drop but you can continue in any size you like, the larger the better. piping design deals with bends and temporary contractions in otherwise larger size straight piping.

 

if you really can't figure it out then you need to find a competent 'arithmetician' and sit down with him/her and go through it on paper. it is not rocket science.

Edited September 30, 2016 by Murflynn

[Chewbacka]

Yes that's fair enough, I've obtained as much info as I can and probably do have everything but I confess I don't have the skill/method to do the equation.

Here's a question though; if you have to reduce whatever pipe that goes in to 10mm as that's the only bubble tester available, wouldn't that defeat the object of using larger pipe after that point in the system?

Did you look at this?? >>>> http://www.installeronline.co.uk/wp-content/uploads/2013/06/Size-matters.pdf

[Polishicebreaker]

Had a look but I'm restricted only to I-phone so it's a bit of a pain to navigate.

So is that chart saying 10mm pipe will only deliver 570g gas per hr over 6 m run?

Had a look but I'm restricted only to I-phone so it's a bit of a pain to navigate.

So is that chart saying 10mm pipe will only deliver 570g gas per hr over 6 m run?

[WotEver]

So is that chart saying 10mm pipe will only deliver 570g gas per hr over 6 m run?

No, it's saying it'll only deliver 0.57m³ per hour.

[Polishicebreaker]

But I don't understand how that relates to my appliance.

My morco which is first in the run uses max 800g per hr and runs at 11.1 kW. The length of pipe is 5.5m with 3 bends, how would I go about calculating pressure drop?

[WotEver]

But I don't understand how that relates to my appliance.

My morco which is first in the run uses max 800g per hr and runs at 11.1 kW. The length of pipe is 5.5m with 3 bends, how would I go about calculating pressure drop?

11.1kW = 0.42m³/hr for propane.

 

See here: https://www.bes.co.uk/products/030.asp

[Polishicebreaker]

I've just cheated and used an app which is coming with 15mm. Interesting

Sorry I just posted that without seeing the previous one.

It would seem 3/8 pipe ain't enough then!

Sorry I just posted that without seeing the previous one.

It would seem 3/8 pipe ain't enough then!

[Polishicebreaker]

I tried the Bes link. That's quite helpful.

 

When I convert my 24kw into m/3 per hr I get 0.709

If I then input that into my calculator taking into account high and low loss fittings it recommends min pipe size of 12mm

However if I input 24 kW( this is an option on the app) it recommends 15mm

[alan_fincher]

if you have to reduce whatever pipe that goes in to 10mm as that's the only bubble tester available, wouldn't that defeat the object of using larger pipe after that point in the system?

 

Without going back through the whole thread, I feel sure I have pinted out you can change the tails on an Alde bubble tester to an imperial size of your chice, including 1/2"

 

You are not limited to just the metric pipe sizes they are sold with - you can modify them.

 

(Apologies if that is in a different thread rather than this particular one).

[Polishicebreaker]

Do you mean the threaded 10mm ends come off then?

They don't seem to want to.

[alan_fincher]

Do you mean the threaded 10mm ends come off then?

They don't seem to want to.

 

Yes, they are screwed into the body of the tester.

 

Or at least they used to be, unless they have changed the design since I last fitted one some years ago.

 

EDIT:

 

Looking at an image of a current one, I can't see why it would have hexagonal faces at the tester body ends of the tails if that wasn't to allow them to be spannered out of the body. Don't try too hard though, in case they have changed the design!

 

Anybody done it on a recently bought tester, please?

Edited October 1, 2016 by alan_fincher

[Murflynn]

I tried the Bes link. That's quite helpful.

 

When I convert my 24kw into m/3 per hr I get 0.709

If I then input that into my calculator taking into account high and low loss fittings it recommends min pipe size of 12mm

However if I input 24 kW( this is an option on the app) it recommends 15mm

when I convert your 24kW into m3/hr I get 2.2.

[Polishicebreaker]

Really, oops I better check that.

Told you my maths is rubbish

[WotEver]

When I convert my 24kw into m/3 per hr I get 0.709

Then you're doing it wrong. It's 0.928.

 

Were you using the equation for propane or some other gas? (kW x 3.6)/93.1 is the equation for propane as per the link I gave earlier.

 

Tony

when I convert your 24kW into m3/hr I get 2.2.

For propane?

Do you mean the threaded 10mm ends come off then?

They don't seem to want to.

Yes they do but they're very VERY tight. Vice and spanner required.

[Polishicebreaker]

Just re-calculated, thanks for pointing that out.

Redone the calculation and I'm still getting 15mm min diameter.

I tried the ends of the bubble tester, they did seem super tight. In that case I'll take them yob the workshop and try.

 

I've just encountered another issue. I've exposed the existing through bulkhead fitting which is 3/8.

It's in a tricky spot under gunnel to remove and replace with 15. The builder has even cut out some of the flat bar on the bulkhead and it only just fits in. It's too tight to get a slitting disc in there. As I have all the stuff to do 3/8, is there any logic to stepping down to 3/8 just to get through the bulkhead and then going back to 15mm or would that be considered bad practice and I should use a 15mm through fitting somehow??

[alan_fincher]

I've just encountered another issue. I've exposed the existing through bulkhead fitting which is 3/8.

It's in a tricky spot under gunnel to remove and replace with 15. The builder has even cut out some of the flat bar on the bulkhead and it only just fits in. It's too tight to get a slitting disc in there. As I have all the stuff to do 3/8, is there any logic to stepping down to 3/8 just to get through the bulkhead and then going back to 15mm or would that be considered bad practice and I should use a 15mm through fitting somehow??

 

If you introduce 2 reducing couplers to go to a smaller pipe size just to get through a bulkhead, then that is 4 more compression joints than is really needed.

 

It has been reported on here more than once, I think, that some BSS inspectors will fail a system that has any more joins than it actually needs.

[Polishicebreaker]

Ok that's good to know. I'd better try and wrestle a 15mm fitting in there then.

[Polishicebreaker]

Ok that's good to know. I'd better try and wrestle a 15mm fitting in there then.

[Murflynn]

 

 

 

 

 

 

[Murflynn]

 

For propane?

 

 

you're right, should be 0.88