hartford loop 6" too low

timgardner

I'm replacing my Burnham PV84SC with a Burnham Megasteam MST396SL which is 6" taller. What is the downside of NOT repiping the Hartford loop which would then be 6" below manufacturer's recommended height?

EBEBRATT-Ed

You need to raise it to what the mfg wants usually 2-4" below the normal water line.

Depending on your system it may or may not matter but if you leave it low you may need to go back and change it.

Steam is very touchy. You have to follow the boiler MFG near boiler piping which is the minimum standard

timgardner

In Dan's book I read that one advantage of the Hartford loop is that a leak in the return piping will only drain the boiler to the Hartford loop level, preventing dry firing in the event the LWCO fails. Are there any other advantages?

ethicalpaul

There's not even that advantage. If the LWCO fails, your boiler is burning up.

EBEBRATT-Ed

With a low water condition and the low water cut off fails to shut the burner down the Hartford loop will buy you a little time like maybe 20 min of steaming if you have a break in a return line. if the boiler is leaking the hartford cant do anything to save the boiler.

timgardner

If the Hartford loop doesn't even help as a lwco backup, how could it hurt me to have one that is 6" too low? There was no time savings to repipe it when I replaced the boiler, and I have unions where they should be so repiping it would not be a huge effort, but why do it if it isn't necessary?

timgardner

ethicalpaul

timgardner said:

If the Hartford loop doesn't even help as a lwco backup, how could it hurt me to have one that is 6" too low? There was no time savings to repipe it when I replaced the boiler, and I have unions where they should be so repiping it would not be a huge effort, but why do it if it isn't necessary?

I don't think that having it 6" too low would cause any problem, but it's better to pipe according to manufacturer instructions because they have done way more testing than any of us. Additionally, it just lets you rule out a bunch of variables if you follow their instructions.

The loop itself is necessary for code from way back when someone in CT had the incorrect idea that it could save boilers. The real thing they should have done was to make buried returns against code.

ethicalpaul

Reading your post again, another question that I have is: why is your new boiler 6" higher? You generally want to maximize the distance from your boiler's water line to the higher parts of the system so I'm curious--why is your boiler on all those blocks now?

Is it because the installer didn't want to install new riser pipes or something?

EBEBRATT-Ed

@timgardner

Basically if all your return lines drop down from overhead (dry returns) then the hartford loop being low is no issue.

If you have wet returns from under the floor,,,,along the floor.....below the boiler water line then it should be raised up

timgardner

@ethicalpaul - I replaced a Burnham V8 with a Burham Megasteam. Both produce the same 396 square feet of steam, but the Megasteam is 6" taller than the V8. The V8 was on the same blocks as the Megasteam so the height of the return did not change. I repiped the risers because they were positioned differently due to the flue coming out of the back of the Megasteam whereas it came out the top of the V8.

timgardner

@EBEBRATT-Ed I do have wet returns along and even under the floor below the boiler water line of the boiler. I do have a Hartford loop: it is currently 6" below manufacturer's specification for this boiler, and I am curious as to why it would matter.

Dave T_2

The branch of the tee needs to be below the water line. When located about 2" below the low water line it is, in theory, at the lowest pressure point of the equalizer, thus the point return water can move easiest. But yours being lower than that will be just fine.

Jamie Hall

There is, sometimes, a very good reason to raise a new boiler on blocks. If there are wet returns, it is essential that the new boiler water line be high enough to ensure that they really stay wet out at the far ends -- and new boilers are often shorter to the water line than old. There are simple ways to cope with a low overhead to steam mains -- drop headers being one of the best -- but if one does manage to dry out what should be a wet return, the resulting havoc is impressive -- and remarkably hard to correct.

Bottom line: if you are replacing an old boiler on a system which is otherwise working well, do whatever it takes to make the water lines match.

motoguy128

I think the best value is a loop in the return creates a point to catch larger debris where it can be flushed out before reaching the boiler.

Really, all boilers should be requires to have tees with valves for flushing and the return connected with a cross. I’d kicking myself for not installing a cross when I installed mine.