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Discussion Starter · #1 ·
I am assembling an Aster Berkshire, my first introduction to live steam. I have encountered a few irregularities during assembly which leave me puzzled. They are:
1. Drain cock valve mechanism: The Drain Cock Cams do not rotate far enough to fully depress the Valve Levers when the hand crank is pulled fully back. This is because the Cam is just beginning to depress valve levers when Drain Horn hits the Branch Pipe on the Steam Chest. I've tried every configuration of these cams: I can fully depress the Valve Levers with the Cams in the reverse configuration as that shown in the instructions when the Horn is pushed (instead of pulled). However, this doesn't work because the linkage to the hand crank just bows up when pushed. It looks like larger cams are needed to fully depress the Valve Lever, or a slightly different angle to the Cam setting which I can't figure out how to adjust. What am I missing here? Also, it's my understanding that the Drain Cock valves are closed when the valve levers are not depressed (cam not touching levers) - is this correct?

2. After successfully sealing threaded fittings on the boiler, the boiler still loses pressure because the ball valve has a slight leak. It takes about 5-10 minutes to fully depressurize from 4 Kg/cm2. Should this leak be eliminated? I put a small dimple in the brass bar when seating this ball per the instructions. Short of whacking it again, I'm not sure what else to do.

Thanks for any advice you can offer to this newbie.
Rich
 

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Hi Rich,

First of all get the boiler back up to pressure and brush some soapy water around all the fittings if you get any bubbles that is where your leak will be.
You say you struck the ball in place as per instructions so I suppose you used the ball in the kit. This could be your problem you should have used a spare so try replacing the ball for new.
You do need to stop the pressure weep because if you need a boiler certificate (as we do in the UK) it would fail.

Keep us posted and maybe a picture or two.:)

Tony
 

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Rich, check to see if the cylinder drains work when you run the chassis on air, it does not take much movement on the levers to open the vavles in the cylinders.
Jeff
 

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Discussion Starter · #4 ·
Thanks for the comments on the Boiler pressure test. I have verified using soap solution that the boiled is pressure tight, except for the ball valve. The valves are also working and shut off properly, so I know the only source of the leak is thru the ball valve - which I can see with soap solution.

I did not realize that a substitute ball should be used in seating this valve as this is not in the directions I received from Aster. I wonder where I can find a replacement ball.

Any comments/suggestions regarding the drain cock valve?

Thanks
Rich
 

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Posted By RichT on 04/21/2008 10:08 AM
Thanks for the comments on the Boiler pressure test. I have verified using soap solution that the boiled is pressure tight, except for the ball valve. The valves are also working and shut off properly, so I know the only source of the leak is thru the ball valve - which I can see with soap solution.

I did not realize that a substitute ball should be used in seating this valve as this is not in the directions I received from Aster. I wonder where I can find a replacement ball.

Any comments/suggestions regarding the drain cock valve?

Thanks
Rich




You shouldn't need a substitute ball as long as you tapped it lightly with a brass rod. If you whacked it with a steel rod, then the ball might be distorted but you probably also have distorted the fitting in doing so! I would check that no sealant or other dirt is interfering with the action of the valve first. You mentioned that you found the leak with soapy water - not sure I understand how this could identify an internal leak in the clack (aka ball) valve - sounds more like the fitting itself needs sealing. The water infeed comes through three ball valves - hand pump, axle pump and then clack valve, so back pressure leakage here is fairly rare.

As to the drain valves, you may need to fiddle with the setting of the drain lever on the shaft - I remember doing this but don't think it was a big deal. I went on to add a radio control servo which works really well as you can see in the openin seconds of this video http://www.youtube.com/watch?v=YpZCK4o1dYs
 

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Discussion Starter · #6 ·
Zephyra - The video of your Berk is really cool. I particularly like the way it starts and stops. Some day I hope to add RC to mine as well, but first...
I used a brass rod to set the ball. I decided to tap it again figuring that I had not tapped it hard enough the first two times. After the third tap, I inspected the ball and it is completely clean, no scores or marks. I wonder how much of a sealing surface I should see in the seat of the ball valve. In any case, I'll see if this helped once the sealing compound cures and I repressure test it.
For the cylinder drain cocks, I suspect I have installed the cam backwards. One piece of information would help clarify this for me: does one push or pull the drain cock valve lever to rotate the cam to depress the valve levers (opening the drain cock valves)?

Thanks again for the info
Rich
 

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backwards on the lever in the cab opens the drain cocks. Its easy to reverse the levers in the cylinders, as they are mirror images.
 

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Discussion Starter · #8 ·
Well, that was it: the cam was backwards.
What a study in careful observation! I don't know how many times I tried turning this cam around to get it right - I thought I'd tried every conceivable configuration. Now, I have full range control of the drain cock valves.

I still can't get the check valve ball to seat for a gas-tight seal. If I could find a viton replacement ball, I'd switch it, but I think I'm just gonna try it as is figuring the water will just condense any steam that back's up here.
 
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