WANTED USED HOFFMAN DIFFERENTIAL LOOP

Rick Salvador

Where would you search to find a used Hoffman Differential Loop (No. 1) to replace a cracked one.

Can the old one be repaired by welding it?

Thank you for you help.... Rick

Joe C

Diff loop

What size do you need?

gerry gill

why?

why do you still need it? does your boiler run on coal?

Rick Salvador

The model is NO. 1. The building is around 2,000 square feet. My boiler was replaced and we found that the loop was cracked. We tried installing a Hartford loop but the water surges from the bottom of the glass to the top. This did not happen while the Hoffman loop was attached.

Thanks, Rick

Rick Salvador

Our new boiler ran fine until we removed the Hoffman Loop. We have added the Hartford loop but there probably has to be more changes done to stop the boiler from surging.

Steamhead

Rick, a Hoffman Vapor System like yours

will run fine without the Differential Loop. The Loop was there to make sure the water could get back to the boiler if the pressure got too high. Nowadays we use a Vaporstat to limit the boiler's pressure to less than 1 pound.

There are two caveats to removing the Loop. 1- Do not replace it with a straight piece of pipe between the steam main and the dry (overhead) return. This will pressurize the return so steam will not flow.

2- Make sure the dry return is well vented. The vent in the top of the Loop was the only vent in the system. Use at least one Gorton #2 vent on the dry return, and if there's more than one dry return they all need either individual vents or access to a central vent. If the air can't move from the radiators into the dry return and out the vent, the system won't heat properly and the boiler may surge.

If you're not sure of the piping configuration, post some pics here and we'll see what we can do.

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Rick Salvador

Gerry,

Here are a few pictures of how the system is connected now.

Steamhead

Near-Boiler Piping is Wrong

We install that line of Columbia (or Utica) boilers so I can tell you it's not right. You'll find the piping diagram in the installation instructions, which the installer probably used for knee pads.

You need a proper header- 2-1/2-inch or 3-inch on that boiler depending on its capacity- with two risers from the boiler to the header and a riser from that to the steam main. Here's a shot of a similar boiler we did- two risers to a drop header, and two steam mains leaving the header.

Also that dry return vent looks awfully small. It's probably a Hoffman #5 or #6. If it's a #6 it's a Vacuum vent, which can do all kinds of strange things to an oil- or gas-fired system. Change it to a Gorton #2 and watch how much better the system works.

www.gorton-valves.com

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Rick Salvador

Gerry,
My steam boiler is a Utica model# PEG300CIDE serial# UAB12596. It produces 182,300 BTU/HR and 760 sq. ft. of steam. There is also another BTU rating on that has it at 299,999 and a steam rating of 15 PSI.

Thanks again, Rick

Steamhead

The PEG-300

needs a 3-inch header. Anything smaller won't let water separate from the steam.

BTW, my name's Frank.

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