# Another newbie question - Goodall valves



## Dr. J (Feb 29, 2008)

Here's another question from a rank newcomer:
When adding water to the boiler with a goodall valve, where does the pressure go? You're introducing a lot of incompressible volume (the new water) into the tank. How do you avoid fighting against the filling pressure? How does this resolve itself if you're using a quick-connect fitting? Are you supposed to leave something else open to atmospheric pressure during the fill process? 
Thanks
Dr. J


----------



## gwscheil (Aug 6, 2008)

The incoming water compresses the air/steam mixture in the boiler. If the boiler has no head space left, then you are trying to compress a liquid - pressure will skyrocket. This condition is used in hydrostatic testing of a boiler.


----------



## Pete Thornton (Jan 2, 2008)

When adding water to the boiler with a goodall valve, where does the pressure go? 

As George said, you are compressing the air and/or steam mixture. If there was no air space then you wouldn't need to add water!


----------



## AzRob (Sep 14, 2009)

Where can one get goodall valves? Where could one install one on a Ruby? I know a couple people have done so, but I don't know where or how.


----------



## HMeinhold (Jan 2, 2008)

By adding water you condense some of the steam and if the pressure gets too high, the safety opens. This happens with my locos, when I top up water with a Goodall type valve. Also adding water with a squirt bottle is pretty slow, so any leakage through the throttle/cylinders relieves (steam) pressure. 
Regards


----------



## turbohvn (Jan 7, 2008)

I manufacture and sell Goodall valves along with the pump bottles for adding the water.

The "physics" described above are correct, but real time use/experience shows this not to be an issue with our small scale and relatively low pressure boilers. Goodall valves are a very simple, and efficient way to add water while the boiler is under steam.

Royce
Quisenberry Station - Live Steam Models 
202-422-2892


----------



## Taperpin (Jan 6, 2008)

Jim, 
When you add cold water via aGoodall Valve or Hand /pump/Axle pump the pressure dops because of the cold incoming water ,, often a lot! it seems to balance out and you can watch the pressure gauge and "time" your pumping to keep just below Pop Off. 

Gordon.


----------



## Dr. J (Feb 29, 2008)

Thanks, all, for your replies. I guess air is more compressible than I thought. And it makes sense that the cold water results in condensation and contraction of the air/steam volume in the boiler. 

For AzRob: Additional sources of goodall valves might include Charles & Ryan Bednarik (http://www.realsteamservices.com/), Bob Weltyk ([email protected] ), and Norm Saley ([email protected]). 

Dr. J


----------



## Jerry Barnes (Jan 2, 2008)

I think Accucraft has one for it also.


----------



## Pete Thornton (Jan 2, 2008)

A note on Goodall Valves. They use silicon tubing and the tubing gets old and fades away. Ask for some spare tubing when you buy the valve!


----------



## turbohvn (Jan 7, 2008)

I supply spare tubing with my valves. However the stuff seems to last forever.

Royce


----------



## RimfireJim (Mar 25, 2009)

Posted By Jerry Barnes on 16 Sep 2009 07:37 PM 
I think Accucraft has one for it also. 
No, they don't. At least, when I asked earlier this year they didn't carry them.
I bought one from seller "mnvjohn" from Las Vegas on ebay, but it doesn't look like he has any listed at the moment.


----------



## Charles (Jan 2, 2008)

Two options for the fill hose:

A metal tube
Quick disconnect

[script removed]


----------



## voxnut (Jul 16, 2008)

After getting the run around from another dealer, I ordered an excellent goodall valve and spray bottle with a reasonable turnaround from Mr. Norm Saley. I'd recommend him to anyone. He can be reached at [email protected]

Dean


----------



## D&RGW 461 (Jun 4, 2009)

Another fun option, Build your own goodall valve, I did for a few of my locos, and a few for other people. I'ts easy just drill a 1/8th hole thru your brass filler cap, and cut a piece of 1/8th K&S tubing about an inch long. ( take measurement of how far down your flue is to make sure it does not reach it when valve is installed ) Then solder a bulb of silver solder to one end of the tubing slightly larger than the tubing. ( to hold the silicon tube from sliding off the 1/8th tube later ) Then carefully drill a 1/16th hole thru, and out the other side of the 1/8th tubing, be sure to drill even and square about 3/8ths from the bulb of solder you just did. Then slide the 1/8th tube into bottom of filler cap about 1/4" and then solder them together. Now just cut a piece of silicon tubing to fit between the bottom of the fill cap and the bulb of solder, covering the 1/16th holes you drilled in the 1/8th K&S tubing. Now just slightly taper the1/8th hole on the top inlet side of the filler, I mean, now goodall valve, to accept the fill tube from your water bottle. Make sure you clean the holes up after you drill and use flux when you solder. That's it, pretty easy to build huh, The first one I made about 8 years ago is still going strong and works like a champ. And yes the same original silicon tube on it also. Have fun, after all, that is the name of the game, right ?? Chris Sortina


----------



## rkapuaala (Jan 3, 2008)

I build my own, and I use tubing that is readily available at any rc hobby shop. Built or bought they are a fantastic addition to any engine


----------

