Fixing a gas stove

[George.]

We have a gas stove on Dalia, made by Broadwater Marine in Oz, and purchased at great expense because it was said to be very very safe. Our 13 kg butane gas containers fit the specs, and it works very well. Except...

It has a safety mechanism that shuts off the gas if the flame goes out. It consists of a copper tube with a wire inside it - one end against the flame, the other coupled to an electromagnetic switch. The thermoelectric effect generates about 2 millivolts, which keeps the switch "on" until the flame goes out.

Problem is that the thing started to switch off the gas with the flame still on. First in the oven, then in the burners. Broadwater Marine has no rep in Brazil and no website or e-mail that I could find, so I took the thing apart myself and tested it.

After much head scratching and testing, turns out that our *#!@&! gas is not clean enough by Aussie standards :rolleyes: :mad:, and leaves a deposit of soot on the sensor tip of the thermoelectric device. Once enough soot builds up - several meals on the stove top, but only 15 minutes or so on the oven burner - the thing stops generating current, and the gas goes out.

If I clean it with a rag, it works again. That's fine for the stove burners, but impractical for the stove - not only does it not last long enough to bake most things, but putting your hand into a hot stove in a seaway is, well, unadvisable. :eek:

We only have one butane distributor in Angra, and his gas is dirty. Bringing cleaner gas from a supplier in Rio is possible but impractical (yes, we tried it and it works).

Question: does the soot interfere by blocking the heat ever so slightly, or by isolating the circuit electrically? Is there any modification to the device that might make it more forgiving of our crappy butane?

[P.I. Stazzer-Newt]

Is the stove jetted for butane or for propane? - are you equipped to measure the diifference?

The usual cause of soot is an improper fuel-air mix - most stoves will use a range of different jet sizes to match the differences in fuel type and regulated pressure - bit of a guddle.

There is an obvious set of bodges, but if you have to ask...

Has this "fault" been apparent ab initio?

[George.]

The manual sez the jets work with butane or propane, as long as the pressure is right. But the manual is very sparse with information, mostly keeping to boldfaced warnings to not even install the damned thing unless done by an "authorized representative."

The fault was not there at first. I suspect our butane distributor either changed or started to "doctor" the gas to make a few extra bucks - unfortunately, it is a problem in the oil-kleptocracy state of Rio de Janeiro, where the petro industry is, shall we say, loosely regulated.

[P.I. Stazzer-Newt]

Two points.

1. If you don't have a Carbon Monoxide monitoring device - GET ONE - really this is important - the soot occurs when you have incomplete combustion of a carbon based fuel - that's the same recipe as for Carbon Monoxide.

2. Your most likely fail is not the fuel, but the regulator, is the output pressure within the specs?

[George.]

1. I do have a gas detector installed in the bilge under the stove. It goes off if I spray for roaches, and it goes off with the tiniest amount of gas (as tested with a cigarette lighter). I do not know if CO activates it, but I would think not.

2. The regulator puts out 2.2 kPa, measured with my home-built manometer. Specs are 1.8-2.8 kPa.

[P.I. Stazzer-Newt]

CO does not tend to sink into the bilge - too light.
Have you checked the regulator since the problem started?

[George.]

Yes, I have tried other regulators, other tanks, etc. Same problem.

If CO rises, what is the danger?

[P.I. Stazzer-Newt]

It is very close in density to Nitrogen - so it neither rises nor sinks.

And is very very toxic - http://en.wikipedia.org/wiki/Carbon_monoxide

I'm struggling to imagine a deliberately intoduced adulterant - which would have these effects, and be cheaper than butane....

Edited to add:
One thing I have seen foul up a gas burner was an spider (or insect) egg case partially blocking the air inlet - but this is unlikely to affect all three burners ar the same time.....

[Ron Williamson]

Wouldn't a faulty regulator only affect pressure?Not the mixture?
The soot is a red flag,but if the flame isn't too yellow shouldn't all be well?

Could you have moved the thermistor while cleaning it and now it can't get enough heat with dirty fuel to make those millivolts?
R

[George.]

The flame is hot and blue until it goes out, and the device works well when clean - produces the right voltage and keeps the gas open.

[Stiletto]

Broadwater Marine Stoves
Maxco Industries Pty Ltd,
Unit 7/20 Loyalty Road,
North Rocks NSW 2151,
Australia

Email:topstoves@maxcoindustries.com (topstoves@maxcoindustries.com)

Supplier Website:www.maxcoindustries.com (http://www.transportweb.com/link/s.12852.21350/)

[skuthorp]

George, if there's a part to be obtained maybe a forumite in Sydney can get quicker service and mail it to you.

[George.]

Stiletto - I just fired off an e-mail to "topstoves"

Thanks to all of you - I hope they answer. :)

[George.]

The e-mail is "undeliverable" - maybe those guys are out of business? :(

[kc8pql]

Try Topstoves@MaxcoIndustries.com (%20Topstoves@MaxcoIndustries.com) , with the capitol letters.

[George.]

Didn't work either.

The website works, but there is no contact info in it other than that same e-mail.

[Stiletto]

Bummer.

Maxco industries website has a phone number that might be worth trying.

(612) 9683 1255
Fax (612) 9683 1266

I dont know whether you may have to dial another prefix to get to Australia

[MarkC]

You have to dial 0061.

Good on you for buying an Australian Stove. The broadwater does bake well.

But as you live in Ethanol heaven - did you try the spirit (ethanol/methanol) stoves like the pressurised Maxi spirit stove? or the ones owned by Electrolux? Ok they are slower, but the spirit is there!

[PeterSibley]

Kerosene !

[George.]

I run a charter business, and I cook four course meals aboard. Ethanol is too slow, and kerosene smells like an airport taxiway.

[Stiletto]

George, how about posting a sample menu sometime, just to feed my envy.:)

[George.]

Typical main courses on board are seafood paella, penne with a salmon and pear sauce, pumpkin stuffed with shrimp... always served with an appetizer, a salad, dessert, and wine, of course.

Crew eat with the guests, unless it's a honeymoon or anniversary, in which case we set up the candlelit table for two between the masts. ;)

[py]

Hmm. I sent an email to the website adress, bounced back. Tried the phone number-went to testra Home Messaging, which is a domestic voicemail service provided by our phone company. Maybe they've gone bust? For international calls dial , 0061 2 9683 1255

[Stiletto]

That meal sounds very nice, thanks for posting.

[Tylerdurden]

Butane is a mixed gas so I can see where you would have problems.
I call it a junk gas because Like LP it can vary in mix and its crap left over from the refining process.
Use fine bottle brushes to clean surfaces and orifice drills to clean orifices, being careful not to enlarge the orifice. If the pilot is sooting it most likely has crap in the orifice and you need to pull it out and clean it. The orifice is usually near the manifold and just before the air mixing holes. If carbon fouling is hard to remove some spray brake cleaner will help but do not use near plastics.

Find the restaurant supplier the good restaurants use and get your butane from them. Chefs flip out on crappy equipment so chances are the gas will be better quality.
Hope this helps, If you were near me I would fix it for you, Thats what I do for a living.

[George.]

Thanks, Tylerdurden. I'll try that today, and I will ask the owner of the best restaurant on Ilha Grande where he gets his butane.

Stiletto: believe it or not, those items are on our standard menu because they are easy to make aboard, especially with some pre-preparation at home. I take the seasonings pre-mixed, the pears for the penne already peeled and chopped in a jar full of white wine, the seadfood for the paella already clean inside a tupperware, etc. Final preparation consists simply of tossing the ingredients into the pot in the right sequence.

However, no pre-chopped onions, garlic, or tomatoes. That has to be done at the last minute, or the flavour is lost...

[epoxyboy]

Butane is a mixed gas so I can see where you would have problems.
I call it a junk gas because Like LP it can vary in mix and its crap left over from the refining process.


NZ has "winter" gas and "summer" gas. The old ford we had running on LPG was definitely sensitive to the change in the mix.

Just a thought - the air inlet has got accidentally blocked off a bit??

Pete