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I wish to upgrade the gas pipe on my boat from the current 3/8" to 15mm. The Morco water heater manual says it requires a 15mm supply (i.e. metric) yet the chandlers only stock 1/2" pipe and fittings, in copper? Surely in the real world everything is now metric? Metric pipe and fittings are a lot cheaper from plumbers merchants and of course more readily available than having to go to the chandlers. I have emailed the BSS people and am awaiting their reply, but thought I would see if anyone here has any good practical views on the matter?

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there have been several threads on this subject. The general conclusion has been that you should use imperial fittings and pipe purchased for the purpose (dare I say from a chandlers).

Metric pipe generally available on the market does not comply with the wall thickness requirements of the applicable ISO/BS requirmentsm which is why it is much cheaper. It tends to buckle/kink during installation.

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The instructions actually specify 10mm for LPG and 15mm for natural gas. 3/8" is as near as dammit to 10mm.

Mike

The Morco instructions I have before me right now actually say for Butane/Propane 3/8" or 15mm.

 

Which, of course, is odd!.................

 

My strong advice, (although I hold no qualifications on the topic), is to stick to Imperial, particularly if modifying a boat where everything is already imperial. If you buy the proper pipe and fittings, there is no dispute that it it meets every requirement for LPG use on boats. As CrisPy said, much of the metric stuff does not strictly meet the wall thickness requirements required for this environment - including some stuff sold by "chandlers" who (in one well known case) will give you advice that is just plain wrong!

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PIPE WORK CONNECTION SIZES

GAS Butane/Propane-Natural 10 or 15 mm.

WATER Inlet (cold) 15 mm.

Outlet (hot) 15 mm.

Flueway D61B and D61E ø 90 mm.

G11E ø 110 mm.

 

I took that 'or' as replacing the hyphen between propane-natural

And also unless you go to a proper plumbers and buy table 'w' flexible copper, you'll end up with too many joints.

Mike

Edited by NBMike
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The Morco instructions I have before me right now actually say for Butane/Propane 3/8" or 15mm.

 

Which, of course, is odd!.................

 

My strong advice, (although I hold no qualifications on the topic), is to stick to Imperial, particularly if modifying a boat where everything is already imperial. If you buy the proper pipe and fittings, there is no dispute that it it meets every requirement for LPG use on boats. As CrisPy said, much of the metric stuff does not strictly meet the wall thickness requirements required for this environment - including some stuff sold by "chandlers" who (in one well known case) will give you advice that is just plain wrong!

 

I voted for imperial from Socal.

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PIPE WORK CONNECTION SIZES

GAS Butane/Propane-Natural 10 or 15 mm.

WATER Inlet (cold) 15 mm.

Outlet (hot) 15 mm.

Flueway D61B and D61E ø 90 mm.

G11E ø 110 mm.

 

I took that 'or' as replacing the hyphen between propane-natural

And also unless you go to a proper plumbers and buy table 'w' flexible copper, you'll end up with too many joints.

Mike

 

The ones I have here are for a D61, and don't include the G11. I think tthere isn't a natural gas version of the D61,or am I wrong ? Certainly my book here implies it is only for LPG.

 

My equivalent of what you have simply says....

 

Butane Propane 3/8 or 15mm

 

No reference at all to any other gas type. So I still think it odd, as clearly if 15mm pipe is used, there would be less potential pressure drop than if 3/8" were used at the same rate of flow, (wouldn't there ?). Just seems wrong to me!

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I wish to upgrade the gas pipe on my boat from the current 3/8" to 15mm. The Morco water heater manual says it requires a 15mm supply (i.e. metric) yet the chandlers only stock 1/2" pipe and fittings, in copper? Surely in the real world everything is now metric? Metric pipe and fittings are a lot cheaper from plumbers merchants and of course more readily available than having to go to the chandlers. I have emailed the BSS people and am awaiting their reply, but thought I would see if anyone here has any good practical views on the matter?

 

Metric pipe is cheaper at the plumbers merchant, because it is thinner walled water pipe, not gas pipe.

 

Metric gas pipe is available, but it is uncommon and expensive. Buying imperial is the cheapest option for pipe of a suitable specification.

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I wish to upgrade the gas pipe on my boat from the current 3/8" to 15mm. The Morco water heater manual says it requires a 15mm supply (i.e. metric) yet the chandlers only stock 1/2" pipe and fittings, in copper? Surely in the real world everything is now metric? Metric pipe and fittings are a lot cheaper from plumbers merchants and of course more readily available than having to go to the chandlers. I have emailed the BSS people and am awaiting their reply, but thought I would see if anyone here has any good practical views on the matter?

 

Imperial is correct it is better quality. In this REAL WORLD thank God everything is NOT metric ( foreign ) metric tends to be used by youngsters who have not been taught proper British measurements in school whilst grown ups still use imperial. :cheers:

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Metric pipe is cheaper at the plumbers merchant, because it is thinner walled water pipe, not gas pipe.

You will find metric pipe specifically sold as suitable for gas in some of the big DIY outlets. However, this is intended for natural gas use at home, not for LPG work on boats, and is probably also the stuff that doesn't (quite) meet the wall thickness requirement.

 

I guess you need to understand things like those EN numbers, because ones like this, (which includes "gas" in it's multiple applications), doesn't quote a wall thickness, I think.....

 

B&Q Linky

 

Mind you, you have to worry about......

 

Copper tube suitable for hot and cold water services, gas services, sanitation and central heating.

 

You would need a remarkably effective macerator loo, for example, to get away with 8mm pipe for the waste outlet!

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You would need a remarkably effective macerator loo, for example, to get away with 8mm pipe for the waste outlet!

 

I shudder to think of the speed that it would be travelling at, or the pressure that it would be under.

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I wish to upgrade the gas pipe on my boat from the current 3/8" to 15mm. The Morco water heater manual says it requires a 15mm supply (i.e. metric) yet the chandlers only stock 1/2" pipe and fittings, in copper? Surely in the real world everything is now metric? Metric pipe and fittings are a lot cheaper from plumbers merchants and of course more readily available than having to go to the chandlers. I have emailed the BSS people and am awaiting their reply, but thought I would see if anyone here has any good practical views on the matter?

Why do you need to upgrade?

 

cheers,

Pete.

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Why do you need to upgrade?

 

cheers,

Pete.

I have been 'reliably' informed that 3/8" will possibly cause problems with a lack of pressure if e.g. the oven and a couple of rings were on, as well as the shower running. I am just trying to avoid BSS problems in the future. I have emailed them but they have not come back to me yet.

Cheers

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I have been 'reliably' informed that 3/8" will possibly cause problems with a lack of pressure if e.g. the oven and a couple of rings were on, as well as the shower running. I am just trying to avoid BSS problems in the future. I have emailed them but they have not come back to me yet.

Cheers

It may not pass enough volume of gas if lots of other gas appliances are on at the same time ''pressure drops''.

 

I have 3/8'' on the mainline but i only have a two burner plus oven and grill cooker and small gas fridge plus a Paloma water heater and its adequate for those.

If you use thin wall tube you will need inserts in the connecting ends to reinforce them as the olives will keep squeezing the the tube and you cannot get them satisfyingly tight and will probably leak,they will of course reduce the internal bore a bit also. I'd use thick wall without question preferably imperial.

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I have been 'reliably' informed that 3/8" will possibly cause problems with a lack of pressure if e.g. the oven and a couple of rings were on, as well as the shower running. I am just trying to avoid BSS problems in the future. I have emailed them but they have not come back to me yet.

Cheers

Another way is a separate run to the water heater if it's not too far, instead of going up a size.

 

The BSS guide can be downloaded from their website. There's some info on pipe thickness in this thread.

 

Pressure drop depends on length (and the number of tees, elbows), as well as gas flow. There's probably some tables on the web somewhere giving details, any of the gas bods here know?

 

cheers,

Pete.

Edited by smileypete
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I have 3/8'' on the mainline but i only have a two burner plus oven and grill cooker and small gas fridge plus a Paloma water heater and its adequate for those.

But, of course, as Smiley Pete has also indicated, the length of run to the appliances is another factor in whether a pipe is adequate overall or not.

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But, of course, as Smiley Pete has also indicated, the length of run to the appliances is another factor in whether a pipe is adequate overall or not.

Yes of course.And any sharp angle like elbows really puts the brakes on,whether it be,water,gas,air ect running through the pipes.This is why on large installations where there are many appliances T-ing off the mainline a Ring main is essential to equalize out and prevent appliances robbing each other when all turned on or at random.

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