Gas regulator sizing

[obbit]

Hi all

 

It seems my gas installer put in a too small gas regulator. It's a 1.5kg regulator for a cooker (oven,grill and 4 hobs) plus a morco water heater (F11e).

He says i need a 4kg gas regulator but I don't trust his judgment anymore.

Is it possible to over size a gas regulator?

 

Thanks

 

Rob

[Taslim]

You just back from a gig and can't sleep too?

 

There are some serious gas bods on this forun who will, no doubt, be along when they wake up with the info you need.

 

Unless you plan to fit an industrial size regulator oversize shouldn't be an issue baced on the fact that most of the time my reg only runs a pilot light.

 

taslim.

[MtB]

Hi all

 

It seems my gas installer put in a too small gas regulator. It's a 1.5kg regulator for a cooker (oven,grill and 4 hobs) plus a morco water heater (F11e).

He says i need a 4kg gas regulator but I don't trust his judgment anymore.

Is it possible to over size a gas regulator?

 

Thanks

 

Rob

 

Broadly speaking you need to tot up the peak gas consumption (in Kg/hr) of all your appliances, and size the regulator to exceed this. The gas bottle also has a maximum output too, so make sure your bottle is big enough. What size are you using?

 

The gas consumption will be stated in the instructions book for each appliance, and should also be marked on a data plate attached to the appliance.

 

No it is not possible to oversize the regulator, as Taslim says, provided you are buying normal kit from a chandlers or caravan shop.

 

 

MtB

[smileypete]

Hi all

 

It seems my gas installer put in a too small gas regulator. It's a 1.5kg regulator for a cooker (oven,grill and 4 hobs) plus a morco water heater (F11e).

He says i need a 4kg gas regulator but I don't trust his judgment anymore.

Is it possible to over size a gas regulator?

 

Thanks

 

Rob

Butane or propane are about 13.7kWh/kg, so the regulator is designed to handle gas up to a rate of 20.55kW.

 

Given a Morco D61 has a max input of 11kW:

 

http://www.morcoproducts.co.uk/stock-5-19/Water_Heaters/D61B.html

 

That leaves about 9.5kW for the stove which may or may not be OK, depending on the max input of the cooker actually is.

 

For instance this boat cooker has a max input of 8.6kW which would scrape by OK, but if it's a big domestic/range cooker it may have a much bigger requirement.

 

http://www.chandlers-online.com/product/Caprice_MK3_Full_stack_Cooker

 

As Mike says the bottle size is important, or the performance of the heater and cooker when used together may drop off sometimes, particularly if using in butane gas in colder weather.

 

cheers, Pete.

~smpt~

Edited April 27, 2013 by smileypete

[alan_fincher]

Given a Morco D61 has a max input of 11kW:

 

http://www.morcoproducts.co.uk/stock-5-19/Water_Heaters/D61B.html

 

That leaves about 9.5kW for the stove which may or may not be OK, depending on the max input of the cooker actually is.

Except he doesn't have a D61,he says he has an F11E which I think has a power of about twice what a D61 has, and will guzzle gas if flat out.

 

It sounds like the regulator is on the margin of being enough for the water heater alone, without anything else being powered as well.

 

As MTB suggests, I'm wondering if the cylinder in use will really be adequate, even if the regulator is upgraded.

 

I can't recall ever having heard before of this Morco being used on a canal boat - the much less powerful D61 is the one generally found.

[alan_fincher]

Broadly speaking you need to tot up the peak gas consumption (in Kg/hr) of all your appliances, and size the regulator to exceed this. The gas bottle also has a maximum output too, so make sure your bottle is big enough. What size are you using?

Having just checked, it seems the maximum off-take rate for the 13Kg cylinders that are the largest normally used on narrow boats is "only" 15KW.

 

That may sound a lot, (well it does to me), but it appears to be a lot less than what a Morco F11E needs at full power (22.1 KW, as far as I can see).

 

I'm sure Mike or one of the other professionals will confirm, but it seems to me that an F11E is unsuitable unless you can run bigger cylinders than the "standard" 13Kg, (or possibly multiple ones of those at the same time?)

[smileypete]

Except he doesn't have a D61,he says he has an F11E which I think has a power of about twice what a D61 has, and will guzzle gas if flat out.

 

It sounds like the regulator is on the margin of being enough for the water heater alone, without anything else being powered as well.

 

As MTB suggests, I'm wondering if the cylinder in use will really be adequate, even if the regulator is upgraded.

 

I can't recall ever having heard before of this Morco being used on a canal boat - the much less powerful D61 is the one generally found.

 

Oh sh*t of course so looking at the manual:

 

http://www.morcoproducts.co.uk/resources/F11E_Users__Installation_Manual_English.pdf

 

It needs a max 1.7kg/hr propane which alone is above the designed capacity of a 1.5kg reg. If the stove and water heater are on one gas pipe I'd also hope the piping is sized correctly.

 

BES Gas & Plumbing sell 4 cylinder changeover kits, with a pair of cylinders feeding each side via hoses with non return valves, so that approach might be an option if one cylinder at a time isn't enough to feed it all.

 

cheers, Pete.

~smpt~

Edited April 28, 2013 by smileypete

[obbit]

Hi all

 

Thanks for all the comprehensive replies.

To note. The gas pipe is under sized massively (this is one of many faults the plumber installed, but it's the one I can threaten him with i.e. getting Gas Safe).

 

To answer some questions

I got the F11e as I needed to have an angled flue, and the plumber recommended this one. I now know he doesn't take over sizing the water heater and under sizing the pipe as an issue.

 

The cooker is a full domestic cooker converted to LPG.

 

The regulator now. (See below for figures used in equations)

Morco F11e

Nominal energy consumption 22.1kW = 3.12kg

Max (unknown)

 

Cooker Flavel Milano ML61NDP

Max energy consumption 12.7kW = 1.79kg

 

Total

Max energy consumption 34.8kW

Max gas usage = 4.91kg

 

This is as I thought, and I'm glad I didn't take his word for it that a 4kg gas regulator is enough. I generally use 19kg bottles anyway. And not all the hobs work. But this will explain why to get the morco working we needed to put the gas knob to max and the water heat knob to minimum. Also, why the grill never seemed to burn very well.

 

A 19kg bottle has a recc outtake of 19kW (Although Morco recommend a minimum of 19kg bottle).

 

Thank you again everyone for helping me get my head around this. I have some hard facts to send to the plumber now.

I wish I didn't have to. I paid the plumber so I wouldn't have to learn all this. Hey ho.

 

Rob

 

Figures

0.512kg = 1litre

0.1411 = 1kW

7.08kW = 1 litre

12.87kW = 1 kg

 

 

[MtB]

I'd be checking this bloke is actually qualified to fit LPG in boats. Sounds to me as though he is a domestic bod working 'out of scope'. You can check his qualifications and categories of gas he may work on on the GSR site.

 

If he isn't both LPG and boat qualified, GSR need to know as he needs to be stopped or warned. If he is qualified, GSR will be pleased to inspect his work and will happily issue him with a formal notice to him to rectify the work at his own expense should they agree it is contravenes any standards or regalations. GSR may not interested unless this is a residential boat, but well worth calling them though to see.

 

MtB

[obbit]

Thanks for that extra info..

 

He is LPG qualified but I doubt he is boat qualified.

 

I'll be getting onto this tonight.

 

 

[The Commodore]

Just to add, a 3.9kg propain bottle has a recomended offtake of 7.5kw so one would need to sum up total gas consumption requirments before buying a bottle.