Hydro Testing

[Soot n' Cinders]

Myself and several guys in my club use spark plug antisieze. Seals up nice without having to put much torque on the fittings, and it also makes removing the washout plugs and safeties easier.

[jscarmozza]

A few boiler questions: who or what authority performs the hydro test, is it the owner, club, state or someone else? Secondly I'm glad to hear the test pressure is 1-1/2 times the working pressure, I was looking at least 2 times the working pressure also. My rationale was an AWWA/ANSI pipe flange is rated for 250 psi cold water and 125 psi steam, hence I thought everything steam related was half the cold water pressure rating, therefore the test pressure should be twice as much (if a little is good, then a lot is better). Now for the sixty four dollar question; do you think water from a dehumidifier would be suitable boiler water? It's atmospheric and shouldn't contain any minerals, wouldn't that make it an equivalent to distilled water?

[SteveM]

A few boiler questions: who or what authority performs the hydro test, is it the owner, club, state or someone else?

The answer is "it depends". It may depend on what your state or club requires, so ask at your local club. You might want to video record the test for proof beyond just having signatures.

Now for the sixty four dollar question; do you think water from a dehumidifier would be suitable boiler water? It's atmospheric and shouldn't contain any minerals, wouldn't that make it an equivalent to distilled water?

Water from the dehumidifier <b>IS</b> distilled water. If you wanted to generate distilled water fast, you could put a hotplate with a pot of boiling water next to the dehumidifier.

The water may also contain dust and the slimy stuff that builds up in the tank of the dehumidifier, but it certainly is going to contain the minerals you are looking to avoid.

Steve

[Fender]

Even though there wouldn't be dissolved minerals in the water, the pH may be too low (acidic). You should test it and add sodium hydroxide to raise the pH to 9 or 10.

[Bill Shields]

sorry to burst anyone's bubble, but water from a dehumidifier is NOT distilled - it is just atmospheric water (humidity), chilled and collected...and is the same water that comes off your air conditioning evaporator and goes down the drain.

It's basically rain water and unless you live inside a boiler...not distilled.

Dust and dirt - for sure.

Acidic - most likely if you get acid rain.

Slimey stuff is growth that lives in the water and the dark when no sunlight or Clorox is handy.

[jscarmozza]

Wasn't thinking about all the stuff floating around in the air; ok, dehumidifier water is off the list for boiler water sources. So there is no standard for hydro tests...it depends...and that's ok too, thanks.

[Bill Shields]

just use water for a hydro...or cheap Gin....matters not..

for operating boiler, that is another story.

If you use water from the spigot, then have it tested and treat as / if needed.

[jscarmozza]

Holy cow!!! I just looked in my dehumidifier sumps ... are they loaded with crud. I never looked in them, just emptied them out in the garden, geez sometimes I would dump it in the dog's outside water bowl. The one in the basement was slimy, I dumped bleach in it, I'm lucky I didn't get legionella! The one in the shop was full of rust, I guess from grinding, welding and whatever. It would be wise to do a little research before asking a question. Thanks for the info guys.

[Builder01]

You sound like you are not associated with a live steam club. This is the very first thing I did when contemplating building a live steam locomotive. Building a boiler and then figuring out what to do with it after is backwards. All your questions will be easily answered by belonging to a club. The boiler certificate that a club will issue you will usually also be valid at other club tracks, which is particularly fun if you would like to run on other tracks.

Hydro tests are initially done at home by the builder in the privacy of your own shop. You will make sure your boiler is correct before taking it to be certified at the boiler inspector at the club track. The inspector may want to see the drawings for your boiler. Check this out before your start building. I took all of my drawings to the club to have a knowledgeable person look over them first. You may need to do an off frame hydro if it is a new build to allow it to be inspected while under hydro pressure. If you don't know what the procedure is, your club will tell you everything you need to pass the tests. You will know everything before heading off to the club with your boiler. Typical first hydro test of a new boiler is 2 times the working pressure, After that, the boiler must usually pass a yearly test of 1-1/2 times the working pressure. These are both cold tests done with water completely filling the boiler. This is usually done with the hand pump. Also, each year, a steam boiler must also pass a "hot" test to prove things like a working pressure gauge, working safety valve(s) and also to prove that you can get water into the boiler with a fire in the fire box. Also, the safety valve(s) must be able to dump steam faster than the boiler can produce it, this is the accumulation test.

Most clubs have forms for these tests that you can down load off the internet. You will know exactly, before you even start building your boiler, what the boiler must do, and exactly what you must demonstrate to the inspector.

Water qualities are also questions answered by fellow club members. They will know the local water and how it reacts to miniature steam boilers. Some clubs have a special water supply because the local water is not good for the boilers.

Joining a club is probably the single most important thing you can do for yourself. Boilers cannot be tested or inspected by an online forum. If you are never going to join a club and only run on a track on your own property. You can do whatever you want, right, wrong or indifferent.

David

[Harold_V]

The one in the shop was full of rust, I guess from grinding, welding and whatever.

Depends. I've owned about ten dehumidifiers in the past 21 years, and know that some of them use steel in their construction. even where it comes in contact with the condensing water. Sure, it's plated so it doesn't rust at first, but if the dehumidifier happens to enjoy a life beyond the warranty (some do), it eventually rusts. So then, what you found may or may not be related to the shop atmosphere.

H

[jscarmozza]

Thanks for the advice Builder.

[SteveM]

...or cheap Gin....matters not..

I'll help drain it

Steve