Hoffman Differential Loop

kkrrjr

I came across a two-pipe steam system with a leaking Hoffman Differential Loop. The leak is about 1-1/2" above the lower fitting on (I believe)the empty pipe side. These must left-right threads so I think I will have to remove both pipes to make a repair.
Any pointers? Does anyone still manufacture the left-right threaded pipes?
What if the pipe inside is corroded or missing?
If I am unable to repair whay are my options?

bob young

right & left

right & left nipples and companion couplings are made in all pipe sizes. their primary application is natural gas piping

Mad Dog

That will be a real labor of love

I would cut the whole thing out and hang it in your shop. Ever since coal went by the wayside, The Hoffman Differential loop, webster traps and the like are no longer necessary. Cut it out and add a few Gorton # 2 main vents. Whatever you do though DO NOT thrwo that puppy on the scrap heap if you do not want it....it is heating history. Mad Dog

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Steamhead

Mad Dog is right

I hate to see a Differential Loop being taken out, but if it's leaking you really have no choice. That said, here are some things to remember:

1. The vent on top of the Loop is the vent for the entire system. Be sure to vent that dry return with at least one Gorton #2, and mount it so it won't close too early from ambient heat.

2. Cap the line connecting the steam main to the Loop.

3. If there are check valves in the return lines, remove the guts from each of them.

4. Replace the Pressuretrol with a Vaporstat that cannot be set higher than 1 PSI. Set it to cut out at 8-10 ounces with about a 4 ounce differential.

The system will now operate as a straight Vapor system, without the need for the Loop. This would also be a good time to make sure all the traps are working properly- including the traps connected between the steam mains and dry returns.

And don't throw out the old Loop!

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gerry gill

i'm jealous

hope you enjoy the loop.....sure look good all painted up nice...i'm green with envy...

Mad Dog

Yanked one out last week

This one goes on my wall - much like a trophy buck, cuz i know Mr Holomun has one already. Mad Dog

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gerry gill

gotta post pictures,

please,please