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[knoby]

I intend to use a cheddar abc system on my new project. I am aware there are problems with the level sensor that works on the sight glass, & was considering using some kind of float inside the glass,. Any thoughts on this?

I appreciate the float would have to have a hole in the centre to allow air/ steam to move through the glass. I was thinking maybe ptfe or something similar would work.

[Ian Robins]

Hi,
ptfe will sink, polyethelene just floats but at the temperatures involved, this plastic would sweel and possibly melt. at least it will block the tube.

I have consididered the screw in switch described by Malcolm beak, but I havent got the bottle t cut into my puffin boiler.

Have you a cheddar ABC and if it is new where and how much did it cost

thanks

ro88o0

[knoby]

I have had the abc unit for years, but never used it. I always intended to build my tug with a steam plant in it, but lack of money made me go electric. now its time to finally make it steam powered, but retro fitting a steam plant is causing a few headaches.
where can i find out about the screw in sensor ? i have heard about it but would like to learn more. im stupid enough to drill a hole in my boiler so maybe this is the answer.
i need to get my thinking cap on, im sure theres an answer to the float in the glass method somewhere out there.

[Ian Robins]

Hi,

Have a word with jerry watson or cheddar valley steam. They were ex cheddar employees. But at various shows cheddar had a boiler with the ABC kit on it and it ran on a test rig basically all weekend, show after show, so the kit must be ok

ro88o0

[Proteus]

One of the problems they had was that a lot where fitted on the Proteus Boiler, these caused a problem because the heat generated by the burner thats why the brought out a Mk2 Proteus boiler that had the sight glass on the other end away from burner , if you have a boiler of any kind , some people fixed it by shielding the sight glass , andprotecting the Glass from light with a small easy removable cover, this helps to intensify the light beam.hey do work very well and I would have another at the drop of a hat.

Proteus

[knoby]

i actually bought the abc from cheddar at a show after watching it for several hours, its a very impressive system.
Its a good point you make about the sight glass being so close to the burner, I am sure this is going to cause me some trouble. the simple solution would be to put another glass at the other end, but of course, this isn't possible on this boiler as theres a superheater built in to that end. ( typical lol )
I am looking into the possibility of making something up to place 1 somewhere in the middle of the boiler, but its not got past the thinking about it stage yet
 do you have any information about the screw in level sensor, or could u point me in the direction of someone who has?
thanks Glenn

[Proteus]

Just extend it back 15mm all it would need is a pair of spacers , amd put a bit of insulation on the back of it.


Proteus,

[wideawake]

I've been pondering this boiler control, or rather water level sensing again.   There's the Cheddar ABC system which is non-invasive and doesn't require any extra tappings on the boiler and there's the Malocolm Beak system using a probe in the boiler, which does need an extra tapping.    I got to thinking about other properties which could be measured to give an indication of boiler water level, rather like the Cheddar gas regulator uses a measure of steam temperature to control the gas valve as it's proportional to pressure.    What I came up with was measuring the weight of the boiler.   This will get less as water is used and could be used to switch an electric pump on and off or to control the bypass on a mechanical pump.    Practically Ithink it's quite achievable with a miniature pressure transducer in the boiler cradle but ATM I've not found such items at an affordable price.  Anyone got any thoughts?

Guy

[roycv]

Hi Wideawake, Is the water filler stopper, for want of a better word, big enough to drill a hole through and put the sensing wire in there.  It would need an insulating sleeve of course but would not spoil the boiler.  You still need to feed water into the boiler from the pump though.
Just a thought,
regards Roy

[wideawake]

Hi Wideawake, Is the water filler stopper, for want of a better word, big enough to drill a hole through and put the sensing wire in there.  It would need an insulating sleeve of course but would not spoil the boiler.  You still need to feed water into the boiler from the pump though.
Just a thought,
regards Roy

Hi Roy

WRT the idea of weighing, I was thinkling generally.  WRT my Maccsteam boiler and indeed the Cheddar boilers the "stopper" or manual filler is also the safety valve so not available to adapt as a probe.   

Cheers

Guy

[knoby]

Hi Guy,
Wrt the weight idea, i think this is possible, but my concern would be: as the difference in weight would be only a few ounces, could the water movement inside the boiler caused when boat is in motion be to vigorous for the weight sensor to work efficiently?  also there seems to be a lack of small enough weight sensors ( at a reasonable price) as you said. I know a few 'boffins' that might be able to help so i will talk to them this week & see what they say.

After reading bunkerbarges comment ,I'm going back to the sight glass theory for now.

cheers Glenn

[Bunkerbarge]

What did I say?

[knoby]

opps  sorry bunkerbarge i  meny proteous

[Bunkerbarge]

Interesting points though.

I actually have a Cheddar ABC system and a probe system purchased very recently from a guy in Orlando.  I haven't actually used either yet so I'm not going to be able to speak from a position of authority but I was also very impressed with the operation of the old Cheddar display unit that I once saw being used at a Deans open day a few years ago.  From what I have heard there can be challenges with the sensor but I was under the impresion that this was due to the fact that the water does not always 'sit' in the glass and can bubble, causing inaccurate readings.  This may be of course particular to one boiler but I do get this effect with my Hemmens Richmond so I'm wondering how to stop this.  A bigger tube may be a possibility but then the probe won't go around it!!

The probe unit I have just bought is a really neat idea though.  The probe and the filling non-return valve are one unit so you use the normal filling connection on the boiler.  One challenge is the fact that the unit needs a 10mm threaded boss and the Hemmens ones are 40 tpi imperial so a new boss or an adapter will be needed.  What I really like about this unit though it the fact that it operates a small reciprocating pump driven by a servo unit.  So the boiler level is controlled completely independently via it's own motorised pump.  I'm looking forward to a play around with this one when I get home.  Disadvantages with the probe are the fact that it has quite a few insulating washers in it's construction and if any one of these shorts out the probe will fail.  Hopefully careful assembly and fitting will help but I do like the idea of the probe and filing NR valve all in one.

If anyone has any thoughts on the bubbling effect in a boiler sight glass I would be interested to hear.