Model Steam Boiler Help Needed, Please

nhp651
2nd January 2010, 15:31
My cheddar puffin plant won't light.

I was finally brave enough to tighten all my unions up, put oil into the displacement lubricators ( proper cheddar stuff) and water into the boiler and aux tank.......I was planning to have a nice little steam with the engines...it's mounted at the mo on a board prior to putting in my model Imara

I turned the gas on at the tank and fired up the igniter........it lit straight away and started to burn inthe boiler .......I didn't realise( not very well up on steam) that the little red unit conected to the gas burner and the release valve to the engines was in fact the gas supply regulater......until I screwed the little nob down, and off the burner went.....a nice bright blue flame ........to begin with..........then it became more orange/yellow as the pressure was slowly building in the boiler, but the burn rate was slowing down.....sudenly the flame just cut out as though someone had turned a light switch off, and it failed to ignite again.

Now before anyone jumps to conclusions, a) the gass bottle is at least 6 ( six ) years old, possibly older as it was given to me six years ago when I bought the steam plant, but b) still has some in that bottle.

could it be that or some other thing entirely.

The plant is a Cheddar maxi boiler and two cheddar puffin engines. The plant was put together by a consumate steam modeller but never steamed and is about 15 years old.

What have I done to cock this lovely little plant up please.

Thanks in anticipation, Neil.

nhp651
2nd January 2010, 19:40
have been told that it could be old gas........does anyone know what the shelf life of these sort of small butane gas bottles is, and what happens to it when it breaks down....cheers.

MWD
2nd January 2010, 21:03
Neil,

If it's butane, unless the ambiant temperature is well above freezing you will not get much latent heat transfer into the gas bottle and hence little if any vapour pressure. Try some hot water over the bottle. Old gas might have some heavy ends accumulated, but I doubt it.

I it's propane then I guess the bottle could be MT.

Hope this helps.

MWD.

nhp651
2nd January 2010, 22:03
thanks MWD, the cylinder is a mixture of propane and butane, and the gas certainly gets throught to the burner through the gas valve on the boiler, but it's as though after 10 minutes of burning the feed through the valve becomes blocked and the gas is cut off.
what do youi mean by the bottle could be "MT",

cheers, neil.

Philthechill
2nd January 2010, 23:49
thanks MWD, the cylinder is a mixture of propane and butane, and the gas certainly gets throught to the burner through the gas valve on the boiler, but it's as though after 10 minutes of burning the feed through the valve becomes blocked and the gas is cut off.
what do youi mean by the bottle could be "MT",

cheers, neil.Neil! Just browsing through and saw your cry for help! First the "MT". It's just an abbreviated way of saying "Empty"! You will often see "MT" scrawled on gas-bottles to let people (especially the gas-bottle supply-wagon driver!!!!) know the bottle (be it oxygen, acetylene, ammonia, whatever) is empty so it's pointless hooking it up hoping to use it. As most industrial-size bottles of gas (oxygen/nitrogen/air etc.) don't "feel" all that different (weight-wise) full, or "MT" (empty) unless it's a liquefied gas such as used in refrigerants, or heating-gas (butane/propane etc.) and then there's a considerable difference.

Re. your boiler. If there's a minimal amount of gas (as you probably know it's liquid under pressure) left in the bottle it may be that after 10 minutes the pressure in the bottle drops (as the gas is drawn-off) and in so doing the liquid in the bottle will get very cold and virtually stop the liquid "gassing-off".
As MWD said, pouring hot water over the bottle will warm the liquid up and it will start boilng-off again. Actually, if your bottle is quite low on liquid, you will see frost start forming on the side of the bottle which denotes where the liquid level is. Is there any frost forming?

Is there not a thermocouple fitted? Usually all gas-fired appliances have a thermocouple fitted, which is, (as you probably know) a safety device to prevent a build-up of gas in the combustion-chamber, of the boiler, to prevent a gas build-up in the event of the flame going out for any reason.

Presuming there IS a thermocouple fitted on your boiler and it may be a bit "iffy" and after 10 mins it breaks-down and shuts the flame off. Probably worth checking-out! Hope these "observations" may solve your problem! Salaams, Phil(Hippy)

nhp651
3rd January 2010, 22:49
thanks phil...that was very helpful............I have had a thought though.(??strange for me)
In April I am going to be hand delivering a model of the Flying Christine 3 [ the ambulance boat opperated by the St John's Ambulance ]that I am doing a build log on, on the tug forum, to her new owners in Guernsey.
As the engines are a direct derivitive of the original that Stuart Models of Guernsey made, and now make after the sad demise of Cheddar models, I am going to phone them tomorrow and ask if they can either sort it over the phone, or whether I can post the plant to them and get it running nicely for me, and I can then pick it up from them in April..........for me that is a brilliant idea.lol
I don't have many of them.

it will save me a lot of headaches, but i really do appreciate all your help, guys.
i just thought it was a case of turn the gas on, click the igniter and stand back and watch.........true to my form, far from the truth. lol
cheers, neil.