Gas pressure question

[jdc]

What make of regulator?

Last year I switched over from a regulator on the butane bottle to a universal (30mbar) regulator mounted on the bulkhead. I bough the regulator from Socal, and it was marketed in this country by Gasboat. I say marketed rather than manufactured since it's made in India and not, I gather, under the direct control of Gasboat.

After fitting it I was disappointed by the weak flame on the cooker, so made a manometer from spare transparent flexible hose (just the normal stuff with white woven 'string' inside polythene). This showed the pressure to be only 5" of water, whereas 30mbar should be about 12" of water (P = ρ . g. h, so h = P / (ρ . g)).

I tried adjusting the regulator but it was apparent that it could never have worked to spec, so I shipped it back to Socal.

I have to praise their service: within 24 hours I had a new one shipped back without any quibble. This one worked and the same manometer read 12". It has worked well ever since with both Butane and Propane. I subsequently had the opportunity to discuss this with Gasboat at the LBS, and gathered that there had been an issue with some regulators which had necessitated a design or production procedure modification.

So my suggestion to the OP is to make a manometer and measure the regulation pressure: it's only a 10 minute task, and whether propane or butane is irrelevant. If it's not delivering the correct pressure, then return it to the supplier and ask for a new one.

 

[Dockhead]

I spent nearly three years suffering from a poorly performing cooker and, especially, oven, thinking that the cooker was bad. I had spent a tidy sum completely overhauling the gas supply system when I bought the boat, and assumed that there could be nothing wrong with it -- so the cooker must be at fault.

What a wrong assumption that was. Turns out that the hoses I had installed at not small expense by a certified gas engineer had some kind of sclerorsis, restricting the pressure. Besides that, the brand new regulator he installed was defective.

After replacing all of that again this summer, the system works like a charm, and lo and behold, my cooker and oven are just fine!

So good idea to have some way of checking pressure delivered at the cooker. I would never, ever, ever put the regulator on a bulkhead, inside the boat, however.

It greatly increases the risk of a gas leak into the interior, for two reasons: (a) you have high pressure gas all the way into the interior of the boat, instead of just between the bottle and regulator; and (b) all those joints and the regulator itself (which can leak) are inside the boat, not out in the gas locker where a gas leak will flow harmlessly away through the vent. Don't do it!

 

[jdc]

Regulator location

... I would never, ever, ever put the regulator on a bulkhead, inside the boat, however.

It greatly increases the risk of a gas leak into the interior, ... Don't do it!

Neither would I! It would be extremely dangerous to have the regulator inside the boat as it specifically has an over-pressure vent built in to it. The place for it is in the built-in gas proof box which already contains the cylinders. This fulfills the requirements of the BSS and is the practice of many boat builders, and is indeed where I mounted mine.

 

[SAMYL]

Surely it hasn't been THAT cold in Essex yet this year! My guess is the regulator as well, especially as it hasn't been used for quite a time. As an emergency temporary fix a squirt of WD40 in each end will often free it, but certainly not advocated as good practice.

Edit: Sorry VicS ....you beat me by 2 minutes <grin>

Do not squirt WD 40 into the regulator. It will rot the flexible diaphragm inside the reg causing a gas leak. Do not tip the cylinders on their sides or the liquid gas will flow into the system.

Low temp will not be the cause of your low pressure, you need to be using a lot of gas to lower the cylinder temp to the level it will cause problems.

Try a simple remedy - give the reg a sharp tap with a small hammer/spanner and that may free up the levers inside because they can jam up if not used for some time.

If that doesn't work buy a new one.

 

[Hadenough]

I have had two "duff" bottles of butane from east coast suppliers in the last two years. On the first occasion when I had exactly the same symptoms as you describe after swapping the empty cylinder for a new one. I renewed the regulator and hoses. When that didn't cure it I cleaned all the burners on the cooker, still no joy. My wife suggested it might be a defective cylinder even though it discharged at pressure with no regulator connected so I took it back. Connected replacement cylinder and Bob was my uncle That was October 2010 ish. When I again swapped cylinders this July with a refill from another supplier but still in the same area, same thing happened. Took it back again, connected replacement and problem solved. Don't ask me why, because I'm told it can't happen but I put it down to duff refills.

 

[VicS]

I spent nearly three years suffering from a poorly performing cooker and, especially, oven, thinking that the cooker was bad. I had spent a tidy sum completely overhauling the gas supply system when I bought the boat, and assumed that there could be nothing wrong with it -- so the cooker must be at fault.

What a wrong assumption that was. Turns out that the hoses I had installed at not small expense by a certified gas engineer had some kind of sclerorsis, restricting the pressure. Besides that, the brand new regulator he installed was defective.

After replacing all of that again this summer, the system works like a charm, and lo and behold, my cooker and oven are just fine!

So good idea to have some way of checking pressure delivered at the cooker. I would never, ever, ever put the regulator on a bulkhead, inside the boat, however.

It greatly increases the risk of a gas leak into the interior, for two reasons: (a) you have high pressure gas all the way into the interior of the boat, instead of just between the bottle and regulator; and (b) all those joints and the regulator itself (which can leak) are inside the boat, not out in the gas locker where a gas leak will flow harmlessly away through the vent. Don't do it!

The system should never be installed like that!

The bottles, all the high pressure hoses etc and the regulator should all be located in a proper gas locker with an overboard drain.
It is usual for bubble leak detectors and electrically operated shut off valves to also be located in the gas locker if fitted.

A bulkhead mounted regulator can be fitted inside the locker.

The gas locker should not be accessible from the cabin.

If high pressure gas has been piped into a regualtor in the cabin by a registered gas installer he should be reported .... at the very least

 

[BlueChip]

Last year I switched over from a regulator on the butane bottle to a universal (30mbar) regulator mounted on the bulkhead. I bough the regulator from Socal, and it was marketed in this country by Gasboat. I say marketed rather than manufactured since it's made in India and not, I gather, under the direct control of Gasboat.

After fitting it I was disappointed by the weak flame on the cooker, so made a manometer from spare transparent flexible hose (just the normal stuff with white woven 'string' inside polythene). This showed the pressure to be only 5" of water, whereas 30mbar should be about 12" of water (P = ρ . g. h, so h = P / (ρ . g)).

I tried adjusting the regulator but it was apparent that it could never have worked to spec, so I shipped it back to Socal.

I have to praise their service: within 24 hours I had a new one shipped back without any quibble. This one worked and the same manometer read 12". It has worked well ever since with both Butane and Propane. I subsequently had the opportunity to discuss this with Gasboat at the LBS, and gathered that there had been an issue with some regulators which had necessitated a design or production procedure modification.

So my suggestion to the OP is to make a manometer and measure the regulation pressure: it's only a 10 minute task, and whether propane or butane is irrelevant. If it's not delivering the correct pressure, then return it to the supplier and ask for a new one.

That's very interesting because I also bought one of these last year from Socal and spoke to them at SBS about the low pressure, our oven never gets hot enough now to cook a Frey Bentos pie and that is a crisis!
It had been working fine earlier this year. They were very non committal about the problem and gave me a string of things to check including calling in a gas fitter, not once was the possibility of a poorly designed/manufactured valve mentioned.

 

[ostell]

That's very interesting because I also bought one of these last year from Socal and spoke to them at SBS about the low pressure, our oven never gets hot enough now to cook a Frey Bentos pie and that is a crisis!
It had been working fine earlier this year. They were very non committal about the problem and gave me a string of things to check including calling in a gas fitter, not once was the possibility of a poorly designed/manufactured valve mentioned.

When I mentioned this problem on the forums earlier this year I was told that a batch of regulators last year had been defective. I also bought my regulator last year from SOCAL. I had trouble getting the gas to stay alight on the burners and boiling a kettle took about 20 minutes. Took up the matter with the importers of the regulators and I received a replacement within a couple of days. Problem resolved.

Edit: Found my post and answers -> http://www.ybw.com/forums/showthread.php?t=312867

 

[Saguday]

Thanks everyone.

The gas (re-)installation was done just over 2 years ago by Will at Gasboat, (and a nice job he did too) so I will check with him about the regulator.

Our boat is American and he swapped out the US propane cylinder for twin calor and the changeover valve plus regulator. It had been working fine up until we tried it last weekend, however as I posted it hasn't been used at all this season.

 

[SAMYL]

I have had two "duff" bottles of butane from east coast suppliers in the last two years. On the first occasion when I had exactly the same symptoms as you describe after swapping the empty cylinder for a new one. I renewed the regulator and hoses. When that didn't cure it I cleaned all the burners on the cooker, still no joy. My wife suggested it might be a defective cylinder even though it discharged at pressure with no regulator connected so I took it back. Connected replacement cylinder and Bob was my uncle That was October 2010 ish. When I again swapped cylinders this July with a refill from another supplier but still in the same area, same thing happened. Took it back again, connected replacement and problem solved. Don't ask me why, because I'm told it can't happen but I put it down to duff refills.

If this happens when a new bottle is fitted it is usually because some air is in the tank, probably it having been left with the valve open. The gas is at the bottom and air being lighter is on top.
Disconnect the bottle, take it outside to a safe area and open the valve for about four or five seconds. Reconnect the cylinder and it will probably be OK from then.
When I was a student I worked weekends delivering and fitting gas tanks and this happened on a regular basis.

 

[VicS]

If this happens when a new bottle is fitted it is usually because some air is in the tank, probably it having been left with the valve open. The gas is at the bottom and air being lighter is on top.
Disconnect the bottle, take it outside to a safe area and open the valve for about four or five seconds. Reconnect the cylinder and it will probably be OK from then.
When I was a student I worked weekends delivering and fitting gas tanks and this happened on a regular basis.

But gases diffuse completely throughout the space available to them.

They do not separate in this way.

I suspect the explanation of what you have experienced is more to do with partial pressures. The remedy will be the same. Vent the air

 

[SAMYL]

But gases diffuse completely throughout the space available to them.

They do not separate in this way.

I suspect the explanation of what you have experienced is more to do with partial pressures. The remedy will be the same. Vent the air

Could be but butane/propane is heavier than air and so accumulates below air, like in your bilges. Why does it not then fill the whole cabin? Explosions happen because people do not smell it because it is usually below nose level i.e. on the floor.

It was the gas company, Calor / Kosan, that gave that explanation.

 

[VicS]

Could be but butane/propane is heavier than air and so accumulates below air, like in your bilges. Why does it not then fill the whole cabin? Explosions happen because people do not smell it because it is usually below nose level i.e. on the floor.

It was the gas company, Calor / Kosan, that gave that explanation.

If LPG finds its way into the bilges it will to some extent be trapped there but even in the bilges it wont sit in the bottom it will diffuse so that the gas concentration becomes the same throughout the space.

After retiring I worked in a school science department for several years.

We used to demonstrate the diffusion of gases in several ways.

One was to put a drop of liquid bromine in a covered gas jar and allow it to evaporate so that by the start of the lesson we had a gas jar full of red/brown bromine vapour.

Early in the lesson the cover was removed and an empty gas jar inverted over the one containing the bromine vapour. By the end of the lesson the bromine vapour will have diffused into the upper jar.
We usually also had one that had been set up the day before. After 24 hours the concentration of bromine vapour was just about equal throughout the two jars.

Bromine (Br2) has an RMM of 160 so the vapour is considerably more dense than air and butane ( RMM 58) but still diffuses at a rate that can be demonstrated easily

I'm surprised you don't remember this demonstration. Perhaps you should dig out your old school science notebooks

 

[SAMYL]

As I said before I was giving the explanation given by the gas company. Perhaps you could try being as condescending to them as you have been to me.

I am well aware of the effects of partial pressures of gasses and how they react physically with other gasses and their solubility in liquids, in particular bodily fluids. I don't need to refer to my old school books thank you.

Regardless of the physics involved the ability of butane to accumulate at lower levels i.e. bilges is well documented.

 

[VicS]

As I said before I was giving the explanation given by the gas company. Perhaps you could try being as condescending to them as you have been to me.

I am well aware of the effects of partial pressures of gasses and how they react physically with other gasses and their solubility in liquids, in particular bodily fluids. I don't need to refer to my old school books thank you.

Regardless of the physics involved the ability of butane to accumulate at lower levels i.e. bilges is well documented.

You cant just dismiss the Physics when it suits you.
Gas may become trapped in an enclosed or semi enclosed space like the bilges but open them up to the cabin and it will diffuse to fill the whole cabin.

However what I was objecting to was your suggestion that any air left in the bottle would, because it was less dense than the Lpg, separate from it rising to the top of the space above the liquid while the lpg sank to the bottom.

In reality the lpg and air will be fully mixed. The concentration of LPG will be equal though the space as will be the concentrations of the gases making up the air.

The solubility of gases in bodily fluids has nothing to do with it.

 

[Saguday]

....aaaanyway..

I have spoken to Will at Gasboat and have the full story on the regulator issue with the manufacturer.

I'm going to try the adjustment option on the inlet side and he's going to send a new regulator in the meantime in case that doesn't work, even though I'm out of warranty (so I offered to split the difference with him).

I'll see what I can do with it all in a week or so's time.

 

[IanCC]

Resurrecting old thread.

So i bought a second hand stove because it is the only one that fits.
Gas guy installs it and it works brilliant. He doesn't do the certificate because he wants to put in new hoses but "use it for now". He comes back, installs said hoses, pressure tests it, it's good. Goes to light it, ni flame, he dives over back of the cooker and fiddles about and it then lights. We have places to go. It then becomes apparent the system only produces enough gas for one burner to work effectively. Since when, new gas bottle, new regulator and it is still the same. I have dismantled the cinnection between cooker and flex pipe and no blockage. I am completely stumped. Oh the gas guy went into hospital with something very serious and emailed saying no charge as he didn't do a very good job but did supply the certificate.

Any ideas anybody? All input appreciated.

 

[superheat6k]

Resurrecting old thread.

So i bought a second hand stove because it is the only one that fits.
Gas guy installs it and it works brilliant. He doesn't do the certificate because he wants to put in new hoses but "use it for now". He comes back, installs said hoses, pressure tests it, it's good. Goes to light it, ni flame, he dives over back of the cooker and fiddles about and it then lights. We have places to go. It then becomes apparent the system only produces enough gas for one burner to work effectively. Since when, new gas bottle, new regulator and it is still the same. I have dismantled the cinnection between cooker and flex pipe and no blockage. I am completely stumped. Oh the gas guy went into hospital with something very serious and emailed saying no charge as he didn't do a very good job but did supply the certificate.

Any ideas anybody? All input appreciated.

Fit a propane regulator and cylinder and see how that works.

 

[Iliade]

If the cooker is really old, is there a screw headed valve on the gas inlet at the back of the cooker? Or a capped needle valve. Or a partially blocked gauze filter.

Corrosion or debris in the manifold inside the cooker?

Try the cooker connected by a short length of hose to the new regulator. If all works you have a plumbing issue.

In an open space check flow from the new regulator (Be aware some regs have a 'pipe failure' automatic shut off.)

 

[IanCC]

If the cooker is really old, is there a screw headed valve on the gas inlet at the back of the cooker? Or a capped needle valve. Or a partially blocked gauze filter.

Corrosion or debris in the manifold inside the cooker?

Try the cooker connected by a short length of hose to the new regulator. If all works you have a plumbing issue.

In an open space check flow from the new regulator (Be aware some regs have a 'pipe failure' automatic shut off.)

Good thinking.