cast iron boiler - back of header equalizer elbow

leftyjazzerman

On a new cast iron boiler installation, does it matter if the elbow at the back of the boiler header which turns down to become the equalizer pipe is a regular (long) radius elbow, or if a short radius elbow will work fine? I'm inclined to think short radius elbow will be fine, and we need to save a some length to fit with flue venting. See attached pdf drawing of location I'm talking about.

But on the other hand I know the header piping configuration is quite a specific design and I do not like to deviate. I once had a contractor use a tee in this location with the header entering in the branch of tee, steam supply up, equalizer pipe down, and I think it caused bouncing uneven water level. But to me the difference between long and short radiused elbow does not seem consequential as long as the proper arrangement of the piping is maintained. What are anyone's opinions on this?

cast iron boiler header piping.pdf

Jamie Hall

Short radius should be fine — but make the pipe size reduction on the vertical section of the equalizer.

EBEBRATT-Ed

Either elbow is fine but keep the equalizer full size of the elbow and then reduce below the boiler water line for best results.

Welded elbows are long or short radius. Screwed elbows are sr and have been used for years with no issue.

dko

Weil Mclain EG manual states reducing elbow or elbow with bushing

Peerless 63 manual states reducing elbow

Utica's PEG near boiler piping technical manual specifically states 2 x 1-1/2 reducing elbow for 3-4 sections.

Only

Burnham SteamMax Manual has in the general piping notes:

A size reduction must be made to connect header and equalizer. This reduction must be made in the equalizer line. Do not make this size reduction in the horizontal header.

If you have a reducing elbow, the reduction is still technically on the equalizer line? So it's not completely clear.

Anyway, I completely understand the reasoning behind not using a reducing elbow. Just odd most of 'em state reducing elbow when they could just say reducing coupling on the equalizer line. As it doesn't seem like it makes it any easier or difficult to follow.. Why didn't they?

EBEBRATT-Ed

@dko

You can reduce any way you want but it may not work. The way I think of it you want the water dumping out of the header into the equalizer like a water fall with no restriction so the foolproof way (if there is such a thing) is to use an elbow full size of the header tapping drop down and reduce below the boiler water line.

Depending on the size of the boiler you can always use bushings, reducing elbows etc but you never know when it will cause a problem. You don't want any water backing up into the header.

Of course, with the old boilers water never got into the header in the first place like it does on modern boilers.

ethicalpaul

Even in modern boilers, no water gets in the header unless it is piped wrong or has horrible water quality.

EBEBRATT-Ed

@ethicalpaul

True in most cases but not all boilers are as good as your Peerless.🙂