Hartford loop

Steamhead

The purpose of the Loop is to keep water from backing out of the boiler if the return line should break. You'll see many older boilers that don't have them, these were likely installed before Loops came into general use. You will also find newer ones installed without Loops by installers who don't know what they're doing (Read The Freakin' Manual!).

The Loop consists of an equalizing pipe from the end of the steam header to the return tapping, and the return main connecting to this equalizer thru a short nipple slightly below the level of the bottom sight glass tapping.

If you haven't already, get a copy of Dan's book "The Lost Art of Steam Heating" which devotes an entire chapter to the Hartford Loop. Order yours on the Books and More page of this site.

Unknown

Hartford Loops

Are Hartford Loops essential for a proper steam boiler installation? What is its purpose, and how would I recognize them in the field?

Unknown

Thanks Steamhead,

Could lack of a Hartford Loop result in wet steam being delivered to the ssytem, or perhaps irratic pressure at the boiler????

Steamhead

No, but

the lack of a proper header would do that.