Orifice Inlets - abandon steam traps

jkvitz · April 27

Henry Gifford's How to Make a Two-Pipe Steam Heating System Really Work (June 2003) page labeled 28, end of paragraph in right column: "There is no need to spend time and money doing anything to the traps. They can simply be abandoned in place."

I get this generally but not fully. If a steam trap is failed closed, how is abandoning okay?

Mad Dog_2 · April 27

I haven't read that, but he has to mean, remove capsule/element and tighten cap, leave body in place. Mad Dog

Steamhead · April 27

This is a valid concept, but unless I was personally responsible for the property in question, I'd leave the traps in. You never know when some knucklehead will come in and crank the pressure up. If the traps are disabled, this will cause banging and steam loss.

JUGHNE · April 27

If failed closed there will be no heat.

The approach is that most failed traps are open and passing steam.

Personally I remove the guts leaving the body in place.

jumper · April 29

»Personally I remove the guts leaving the body in place.«

Good idea. If too much steam is admitted you can easily add outlet orifice as well.

Dave in QCA · April 29

After purchasing the building, I repaired all of the steam traps throughout. Then, we encountered problems in steam distribution. Eventually it was solved by installing inlet orifices sized at 8 oz. I am happy that we having working traps in place too…. a belt and suspenders thing, if you will.

Pumpguy · April 29

Removing traps or their elements will still allow steam to enter the return lines if the pressure is too high.

This will result in all the same problems the inlet orifices were supposed to solve.

These problems show up primarily in the shoulder seasons when steam is up only part of the time.

guzzinerd · April 30

https://forum.heatinghelp.com/discussion/comment/1800367#Comment_1800367

So it's ok to run a 2 pipe system without the trap capsules? My vapor stat is set at 1.5 psi but usually shuts down via thermostat between 0.5 and 1.

Jamie Hall · April 30

https://forum.heatinghelp.com/discussion/comment/1800619#Comment_1800619

Well yes, sort of. But you need to have very tight control of the steam pressure to avoid problems. Orifices — or in older vapour systems which haven't been "modernised" the inlet valves — are calibrated to work within a narrow pressure range — typically five to seven OUNCES per square inch. Further, the venting (usually just a single main vent or vent cluster on the return) and the piping and boiler hopefully bring the pressure into that range quickly — within a few minutes — and then it holds there. This requires the boiler to be accurately sized to the system, of course.

Remember that the flow through an orifice or similar device is proportional to the square root of the pressure difference — so, for example, if your orifice is sized to fill the radiator to 80% at a four ounce differential, you will get twice as much steam in there at 1 psi — and as a result, steam in the returns and the resulting problems. It's all about pressure control.

Or traps…