Hartford Loop tee - orientation question

Ron Jr._3

Had a steam boiler install fail inspection .  We dropped the equalizer right into a bull headed tee for the Hartford L . The tee is 3 inches below the normal water line . One run of that tee drops to the system return with a street ell . The other end of that tee has about 12 inches of horizontal run then drops into the boiler return . I made a crude diagram to show how we piped it .  Was the inspector right to fail it ? Since all that piping is below the NWL all the time , I'm not sure ........  

JStar

I would say...

...it's piped wrong. Looks like the equalizer can very easily push steam into the returns. Was there a reason you did it this way?

nicholas bonham-carter

failed hartford loop

most mfg's specify a very short close nipple for the connection of the equalizer to the wet return leg, and this inspector must have seen that in the instructions. if the waterline, or pressure become unstable, that horizontal in your sketch could be uncovered and start to hammer. one mfg even supplies a "y" for the hartford loop.--nbc

gerry gill

Hi Ron-- as far as function goes,

it would work just fine in my opinion..the only concern i would have is if the 12 inch horizontal pipe was exposed above the water when the water is at that magical point where it is just about to call the feeder on or activate the LWC..at that point is there any hammer? if not it would fulfill the 'function expected of the hartford loop'' as far as i could see.

Ron Jr._3

Thanks for the responses

I can gurantee as long as the LWCO functions properly , no steam would travel into the return piped the way we did it . 3 inches below the water line doesn't seem like alot , but it's a ton of surface area in a Peerless ECT3 . That'd have to be some SERIOUS surging to get steam into the return .



If for some strange reason the water level did go below the HL tee , steam would push from the equalizer into the system return no matter how you pipe the Loop ...................... no ?



As for the why ..........  I'm not positive but I think there was something in the way of us piping it normally . I remember it being a TIGHT spot with a gas water heater in there too . Don't have any pics though , musta forgot my camera that day .



BTW , this same inspector failed another one of our steamers a few years ago .



For having a drop header ...........



Thanks again fellas !

Charlie from wmass

One concern of mine would be this

some how the horizontal pipes at that height seem to love to gather crud. I had one I took out this summer that was 6 years old and had a 1/2" crust inside the pipe I will find the photos and attach later.

Dave in QCA

Return should connect with a close nipple or a Y

It looks to me like the way you piped it would probably work ok as long as everything else in the boiler was functioning normally, which we all know is not always the case.

Dan Holohan in The Lost Art of Steam Heating, pg 64-67 specifies that the wet return loop piping should rise up, then elbow into the equalizer through a "close" nipple.  Many older diagrams will show a downward pointing "y" fitting, because the area of potential steam/water contact would be even less.

The Peerless I&O Manual for the EC/ECT-03 boiler is rather sketchy.  (see pg 6 of attached file)  However, it does refers the installer to another document called Steam Survey.  (see attached file) This document is very specific about the proper connection of the return piping to the equalizer.  While it does not put the requirement of the close nipple in writing, the illustrations are very clear.  Acutally, compared to most I&O manuals, this is a great publiction and shows and explains a lot of system configurations.

As I understand the problem with the configuration as installed, if the water happened to drop to the level of the return connection, which it should not as long as everything is working precisely correctly, you would have both steam and water in a horizontal pipe that is 12" long and it would hammer up a storm.  If the water lever dropped to the same level in a system in which the return was connected by a close nipple or a Y, the area of water and steam contact would be minimal, and should hammer very little, if at all.

As far as pushing steam down into the return line as you commented, either set up could do that, but only to the extent that pressure able to displace the water, probably in the vertical section of the return pipe.  There would be no hammer, because the contact area of the steam and water would be no greater than the diamter of the return pipe.

I am a novice at low pressure / vapor steam.  My years of experience were in high pressure institutional systems.  So, you just have to consider the source and the fact that I may not know what I am talking about at all.       However, I'm sure that I have it right..... well uh.... maybe......

Ron Jr._3

YOW !

That's some serious crud !



Sometimes we see it that bad in a wet return that goes directly into the boiler  . Was that pipe off the ground ?

Ron Jr._3

Thanks Dave for the detailed response

I'll agree there's more of a chance of steam flowing into the return the way we piped it . But that chance is extremely slight .



If for some reason the water level drops below that loop tee and is still firing ...................  the boiler has more serious issues than the **** backward way we piped it 



Thanks again . Yeah Peerless has some very handy manuals . I still think I have my copies of " The Color of Steam "  and  " The Color of Hot Water " they put out years ago . Easy to understand guides .

Charlie from wmass

That pipe was at the low water line

the equalizer dropped down and then went horizontal before dropping into the back of the boiler. The wet returns were actually much clearer.