Trycocks

[johnp]

I don't see too many wt boiler with trycocks. Is it okay not to have them on a wt? How would I mount them?

[fredrosse]

The ASME Code states that gauge cocks (try cocks) are not required. However for a boat boiler they are highly recommended. If indication of boiler water level is lost due to a broken sight glass, then the boiler must be shut down. This is no particular hardship for some applications, but shutting down the propulsion boiler when out in a seaway can be most inconvenient, to say the least.

The ASME Code requires several threads (of pipe threads) to be engaged for shell connections, better yet, a welded "thread-o-let". I have used 1/8 inch IPS threaded try cocks on small boilers, and as this pipe thread has 27 threads per inch, legal thread engagement can be obtained with a shell wall thickness as little as 0.2 inches.

I have a very large stock of 1/8 inch Schedule 80 pipe nipples, 2 inches long, if you need some.

Any SBA members have additional information?

[barts]

Fit a reflex gauge - virtually zero chance of breakage, and no try cocks needed.

- Bart

[SailorHarry]

Just another thought:

The bottom of the gauge should have a drain valve for blowing down the glass. If the glass were broken you could plug the top of the fitting (where the glass would be) and use the drain valve as a try cock. It would get you back to the dock. Super-prepared-steamer-man could have just such a plug in his tool box on board.

Maybe I'll remember to do that.

Peace,
Harry

[marinesteam]

Any thoughts on a second sight glass? Redundant or a wise idea?

I know it may be difficult to find room on a WT boiler so may not be appropriate for JohnP.

Ken

[barts]

With two sight glasses in use at the same time you're twice as likely to have a failure.

If you're using a traditional sight glass:

* use safety gage cocks w/ checks
* fit a shield to protect eyes from flying glass & steam
* carry a spare glass.

I find it easier to use a reflex gage, which is pretty much bomb proof.

Since my small 19' boat doesn't venture offshore, and there are lots more
plausible failure mechanisms that would disable the plant, I find this sufficient.

- Bart

[Dhutch]

If you're using a traditional sight glass:

* use safety gage cocks w/ checks
* fit a shield to protect eyes from flying glass & steam
* carry a spare glass.

Sounds right.
- Obviously with the glass gone, once isolated, you can use the two cocks as try-cocks.

We have two gauges in operation at all times. One covers normal operating range, the other extends down to the lower tube plate or crown but does not go quite as high as the main glass.


Daniel

[cyberbadger]

The ASME boiler code is fine and good, but it's evolved and been edited so most of it's not always a good reference for hand fired boilers. A reflex gage maybe "bomb proof", but when it lies to you it may make your steam launch a bomb... When on the water I prefer redundancy. We maybe on the water, but if their isn't enough water in the boiler well...... If you have trycocks on your boiler, learn how to use them and try them regularly. Learn how to PROVE your sight glass. If you can't isolate your sight glass and prove it, good luck to you. (A sight glass that can't be proved can lie) If you only have a water column, again good look to you. (They can get clogged and lie)

The new ASME boiler I'm getting for my launch didn't require it but I stipulated I wanted trycocks and I'm getting them.

-CB