Dan H., Steamhead, et. al. -DF

hot_rod

I am in the process of restoring a Hoffman Vapor system. It has a differential loop with the original Hoffman vacuum vent. I will be replacing this vent. This is the only vent in the system. The current (3 y.o W-M) boiler is oil fired. Should I replace this with a standard main vent or a vacuum vent? TIA -DF


<A HREF="http://www.heatinghelp.com/getListed.cfm?id=262&Step=30">To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"</A>

ta finnegan

Suggestions

If you can take it off without damaging it, do so and see if you can look in. See what kind of condition it is in. Seems like it should be a Hoffman No.11 Vapor valve?

Are you sure it is not funcioning?

Be VERY careful of your water line.




To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

DanHolohan

I'd use

a high-capacity, standard vent.

Steamhead

Dan, is that

the original (2 vertical pipes about 1" diameter) or later (one vertical pipe about 2" diameter) version of the Loop?

The original would have had a Hoffman #11 vacuum vent (or two on larger systems), which is about the size of a small coffee can, screwed into the top of the Loop. This is the biggest, fastest vent I have ever seen. Hoffman also made a non-vacuum version called the #10. I wish they still did.

The later version had a #15 vent which was installed in a tee on the dry return near the Loop. I have never seen one of these but it probably had a capacity similar to the #11.

The steam mains on these systems were vented by thermostatic traps discharging air into the dry return. From there it traveled to the vent at the Loop and left the system. If these traps go bad, steam distribution will suffer.

The biggest vent I know of that's being made today is the Gorton #2. That's what I'd use on your system. It is a non-vacuum vent but that's fine when burning oil or gas. If you can hear the air rushing out of a single #2 as the system is heating up, install a tee and a second #2.

www.gorton-valves.com

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

hot_rod

Thanks...

everyone for the suggestions. Steamhead, the Hoffman loop is the later style - one 2" vertical pipe with one main vent. I could not get any numbers off of it but it appears to be the original.

The boiler was replaced three years ago and they dropped the water line about 20". Now the loop seals are above the water line. The house does not heat well and the fuel bills are very high. I will post before/after pics. -DF


To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

John Shea

1924 American Boiler Hoffman #1 differential Loop

I am useing a 1924 American Boiler original coal fired now natural gas fired in a 1913 5500sq ft 2 story in. There is a Hoffman #1 differential loop that used to rattle a bit but has stopped. The system is low pressure two pipe system with radiators throughout the house. This has been the most even heating I'v seen however, the pressure raises very little (5lb) after an hour or two and then on cooling developes a substantial vacume (25lb). I suspect the differential loop is not working. First, is an original differential unit available. If not, any suggestions on replacement

Unknown

Go back and study them some more.

They have no moving parts to fail.

They function at pressures below one pound of pressure. Yours never returns to the low pressure water level, until the boiler shuts off.

They serve to pressurize the returns with steam when the steam pressure gets too high. This stops the heating process, but allows the water to drop back into the boiler under overpressure situations.

With the correct pressure control setting, they never function. The pressure never gets too high.

Noel

Mad Dog

Dan F. I restored one over the summer, I used a battery

of Gorton #2s (3 or more). This puppy heats faster than a spooked racehorse. Mad Dog

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Mad Dog

We also did one in a turn-of-the century huge mansion



To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Mad Dog

We also did one in a turn-of-the century mansion





where I used 13 Gorton #2s strategically placed throughout the system. We cut heating time (all rads in house hot)by 60%. Gotta love those Gortons. Mad Dog

Steamhead

Carlton, I agree with Noel

One thing you need to do is turn the pressure control on the boiler DOWN. Five pounds is way too high. If you have the usual little gray Pressuretrol, turn the screw on top until the pointer is all the way to the bottom of the scale. Then TURN THE POWER OFF, remove the cover, turn the little white wheel until the number 1 points to the front of the control, replace the cover and turn the power on.

The control will now stop the burner at 1-1/2 pounds, and restart it at 1/2 pound.

Since the boiler is that old, it's probably inefficient- especially if it's a round one. Replacing an old round boiler with a new one may cut your fuel consumption in half. Try the Find a Contractor page of this site to locate someone who can tell you for sure. If you're in or near Baltimore, e-mail me!

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"