How not to do a Hartford Loop

Randy-LeeBraman

Got a call from a friend who asked me to come look at some work his landlord had a local plumber do to repair on a rusted out mud leg on the loop,this is how he did it,think you want him to come do your work?

Randy-LeeBraman

trying to post pictures but it just sits there and says uploading what am i doing wrong?

Randy-LeeBraman

ahh finally a pic for all to admire,don't you wish you did work like this.

Eric_32

What happened to the equalizer?
Do you have any other shots higher up at the header?

Oh boy...

Randy-LeeBraman

Eric i guess you could say he figured it wasn't needed.The smaller of the two pipes was the Equalizer but he put it back as he did.This same guy charged the landlord a very outrages amount when the low water cut off tripped to reset it takes his chair and tools and makes like its a big project to fill the boiler and push the reset button,heres another picture.

Paul48

I kinda like the union, right next to the csst.

nicholas bonham-carter

There could be some water hammer in that arrangement.
God bless those plummmmmmers!--NBC

SWEI

RTFM, anyone?

nicholas bonham-carter

What is RTFM?--NBC

BobC

Manual, we don't need no stinkin manual!

Bob

icesailor

BobC said:

Manual, we don't need no stinkin manual!

Bob

Who has time to read any stinkin' manuals? I know everything there is to know, and I've never forgotten anything I ever learn'ted.

j a_2

My honest opinion, if one needs to read a manual to repair a broken,rusted pipe he/she is in the wrong business….There are lots of people out here who call themselves, plumbers…Repairing of a heating pipe does not require a lic. here in Mass…The word plumber is used very commonly by handy men/ techs…They can only wish….In Mass it requires a lic. plumber to do a complete install on any boiler….as well as a lic elect...

icesailor

In Massachusetts, the only part of a boiler install that is required to be done by a licensed Massachusetts Plumber is the protected water connection. After that, and you can hire a Great Ape to pipe it up. And some look like that is who was hired to do the install. Unless the boiler is over 400,000 BTU's in which case it is supposed to be installed by a licensed pipefitter. And licensed and inspected by the Dept. of Public Safety.

Any fool can do heating. And some of those fools do.

30+ years ago, they gave out grandfathered pipefitters licenses to qualified plumbers, heaters and pipefitters. If you didn't get one them, you'll be taking a test and having everything inspected.

Plumbers aren't pipefitters, and pipefitters aren't Plumbers. Unless they have a valid Plumbing License.

Heaters may be Plumbers also, but they aren't plumbers unless licensed. If Heater can't take out a Plumbing Permit, he isn't a Plumber.

KC_Jones

I know this is far from the primary concern here, but...all that pipe dope not cleaned from the joint to me is a fantastic indicator of how much this person cares about their work. I am just a homeowner and my joints look better than that.

EBEBRATT-Ed

actually I think the pipefitter license starts at 700,000 btu and up (used to be 3 million btu) so anyone can install a boiler under 700,0000, howeaver a plumber is supposed to do the water and an oil burner license (for oil) or a gas fitter/plumbers license for (gas) and don't forget the electrician unless your an oil guy doing the reconnect on oil.

Don't forget to apply for your new process piping license in MA. new applications on their website. Grandfathered if you have a plumbing or pipefitting license now.

ONLY IN THE GREAT STATE of MA.!!!!!!!!!

STEAM DOCTOR

There is nothing inherently wrong with separating the hartford loop and the equalizer. The hartford loop is there to prevent dry firing in case the wet return pops a leak. The equalizer is a combo pressure equalizer and drain for the header. In theory, the equalizer can connect anywhere between the end of the header and the low point of the A dimension.

STEAM DOCTOR

Obviously, if the equalizer connects to far from the boiler, there could be low water issues in the boiler. Point is that the equalizer and the Hartford loop have two distinct functions and do not need to be connected to each other

RobG

With todays technology if I didn't do the install I want to look at the manual, if for no other reason than to show the owner what and why I'm doing what I'm doing.

Jamie Hall

STEAM DOCTOR said:

There is nothing inherently wrong with separating the hartford loop and the equalizer. The hartford loop is there to prevent dry firing in case the wet return pops a leak. The equalizer is a combo pressure equalizer and drain for the header. In theory, the equalizer can connect anywhere between the end of the header and the low point of the A dimension.

Provided one thing: the Hartford loop absolutely must have some sort of venting at the top of the loop, so that it can't siphon the boiler. This is most conveniently the equalizer, but in principle it could also be a drip from a return. The arrangement shown will siphon the boiler if there is a leak in the wet return.

STEAM DOCTOR

Is there a difference if the" vent" is connected directly to the Hartford loop or a few inches down

Jamie Hall

The siphon will function until the water level in the boiler reaches the level of the vent. If that's a few inches down, then that's the level to which the boiler will drain -- not the top of the loop. Which may or may not be OK, depending on where that level is.

j a_2

As far as i know wiring of any oil boiler falls under under a Massachusetts advisory ruling Mass general laws chapter 30a sec 8…as to the type of electrical wiring which may be performed by oil burner techs certified by the dept of public safety…Its pretty interesting….It appears the oil heat council contacted the state board of examiners of electricians by letter dated dec. 3 1993….Maybe there is a update but I am not sure…I have a hard copy of the advisory ruling, that I was given some time back...

EBEBRATT-Ed

JA your correct. An oil burner tech can replace a boiler (in ma) and reconnect the wiring without having to call in an electrician. Limited to within 10' from the boiler or from the firomatic down I think.

ChrisJ

Jamie is correct,

That is not a hartford loop, it is a speed bump. The vent must be at the top of the loop to break the siphon.

STEAM DOCTOR

Good morning. My grasp of syponige is not very good. Please be so kind to explain in as much detail as possible. My limited understanding tells me that if the vent is between the boiler and the leak in the wet return, then the siphon will be broken. Thank you in advance.

Jamie Hall

To properly understand how a siphon works -- and to see why a vent at the top of a siphon will cause it to not work, but why a vent somewhere else won't affect it -- it is necessary to consider the energy of the liquid. That energy is composed of two parts: kinetic energy, due to its motion, and potential energy. In a situation such as this one, we can ignore the kinetic energy (although to understand a venture, one must consider it). The potential energy itself is also composed of two parts: the pressure in the fluid, and the elevation above some datum of the fluid. We must use absolute pressure, not gauge pressure. Absolute pressure is the pressure in the fluid relative to a perfect vacuum. Gauge pressure (which is what most of our gauges measure) is the pressure difference between the absolute pressure and the local atmospheric pressure. The energy due to elevation can be converted into pressure -- or vice versa -- using the density of the fluid. Thus it is possible to talk about so and so many feet of head, for example.

Now the energy in the fluid in a siphon must remain constant. You are neither adding nor, for our purposes here, subtracting any (there are friction losses, which subtract energy -- but let's ignore them for the moment at least). As the fluid moves through the siphon, it can exchange pressure for elevation, and vice versa, so long as the total is constant. Thus suppose we start in the boiler, since we are talking about boilers, and let's also suppose that the boiler is cold, which makes life a little simpler since we don't have to worry about the boiler pressure. Let us further suppose that the reference we want to use is the basement floor, since it's handy. At the boiler water line, the total energy of a packet of water is its absolute pressure, which is equal to the atmospheric pressure, plus the elevation energy head. As we go down through the water in the boiler, that total stays the same -- there is less elevation, but the measured water pressure will increase by exactly the same amount. Now let us follow our packet of water out into the siphon. It goes along horizontally -- no change in energy. As it goes up the upward going leg of the siphon, the elevation energy increases, and the absolute pressure decreases. It can continue to rise in the upward leg until the absolute pressure drops to the point where the liquid starts to evaporate -- somewhere around 33 feet above the water line in the boiler, at sea level. It then goes over the top and, as it comes down the other side, the absolute pressure will increase by exactly the same amount that the elevation decreases.

If we then provide an opening for the water somewhere out there, such as a leak, water will flow out of that opening, but it can continue to flow through the siphon, as the absolute pressure in the siphon can drop to offset the elevation difference.

Now what happens if we provide a vent at the top of the siphon, what happens? Quite a different picture. Our packet of water, on encountering the vent, must have an absolute pressure equal to the atmospheric pressure at that point. If it tries to drop below that, it will simply suck the atmosphere into the pipe, and the liquid cannot continue to flow (note that if that vent is a hole in the pipe, not a vent, then water will flow out of the hole if it is below the boiler water line -- I'll get back to that). Thus a vent -- or in the case of a Hartford loop, the equalizer -- will keep water from rising in the siphon any higher than that connection, so it cannot flow over the top and down the other side.

A Hartford loop is normally set a couple of inches below the boiler water line, and vented back to the boiler through the equalizer. In this arrangement, if there is a leak somewhere in the cold returns out beyond the Hartford loop, water will flow out of the boiler and through the Hartford loop until the water level in the boiler equals the elevation of the bottom of the loop nipple, at which point it will stop -- thus preventing the boiler from draining completely, which is the objective of the exercise.

I hope this helps...

Hap_Hazzard

Am I seeing things or did somebody replace the gauge glass with a piece of 1/2" copper?

ChrisJ

Hap_Hazzard said:

Am I seeing things or did somebody replace the gauge glass with a piece of 1/2" copper?

No,
It's just so well maintained and clean that it looks like it's metal.