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Y-strainer before main vent - 20 mesh OK?
of that quote from Dan?
In the forty years I've worked on steam I have never seen a wye strainer before a main vent. Nor would I advise one now.
The water that would collect in the clean-out would be just like a puddle in the main.
The installation of main vent(s) at the end of the main is problematic. The solution is to mount the end-of-the-main vent at least 12" from the actual, physical "end" - on a tee. This prevents steam driven condensate from "crashing" into the tee - incorrectly how many did it - and shooting up with enough force to "toast" the vent's fragile guts; rendering the vent useless and leaking for the next 20 years.
Even the best of the dead men installed the vent tees at the end of the main, creating a bull-headed arrangement that was sure to blow the vent up in short order. Some even tried to stick a 12" nipp up to the coupled vent, to avoid this dynamic - to no avail.
Take a look at page 85 of TLAOSH.
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