Should I replace everything

Snowmelt

Here is a pic of some steam traps I was at today. The gate valves should be changed to ball valves?

Snowmelt

neilc

if you're going to service the traps, and use the valves for isolation, then you better have a couple ball valve with you,
if those weren't exercised thru the years they may fail closed.
that's why that one ball valve is on that return.
You stand better chances of them reopening if you turn em down a bit, then back open, then back down a little more, then back open, rinse repeat.
And they can still fail closed after this, so have a ball valve or 2 with ya.

JUGHNE

Are these valves necessary? Engineers put these on drawings all the time. And 50 years later they fail if you use them. Yes, gate valves were the only thing available then.
But, unless the system has to stay on line while you service an F&T, it is simpler to just shut the steam boiler down. All the piping involved should, in theory, drain down.
You may not have this much room to work with, but the strainer has blow down valve, after that there were 3 G-2 vents added on that 3/4" riser with the valve, then the F&T, after that another blown down valve to test for steam getting thru the F&T.
So with the system operating you can blow down the strainer to clear it, (careful of the steam) and monitor any steam passing on the other side of F&T. This is in a shower room so I do not need to catch anything.

The Hoffman design with the 4 ports let you use the extras for testing or air venting. This is straight thru F&T as there was little drop to the dry return.

GroundUp

What's local code say? Some municipalities around here will not allow any sort of ball valve on steam. Period. I found this out the hard way

EBEBRATT-Ed

Their are many ball valve listed for steam use, even high pressure steam. I know the standard "Apollo" valve are ok for low pressure steam and they have others including carbon steel ball valves. Gates are ok if they are decent quality$$$$$ The cheap ones are only good for my scrap pile

JUGHNE

But are any valves necessary or required for isolation of servicing?