Heating Help

water feed on which side of the Hartford Loop

I checked the Wall for this question and found conflicting answers, so I figured I'd ask directly: Which side of the Hartford Loop should the water feed be on?

The contradictory answers all gave good reasons. Put it on the boiler side so that the water gets de-oxygenated as soon as possible and will cause less rust. Put it on the wet return side in order to avoid the temperature shock danger of introducing cold feed water to a hot boiler.

Now let me give some particulars of my situation to see if they might over-ride the general principle. My boiler piping diagram calls for wet-return side. Also, I'm not too thrilled about the two places I have on the boiler side: below the boiler tapping above the mud leg or above the boiler tap just below the equalizer. And finally, would using a water feed from the water heater change any of this? I imagine it de-oxygenates some, but enough? Is it hot enough to prevent thermal shock?

thermal shock or oxygen corrosion?

http://www.heatinghelp.com/forum-thread/137464/Hot-water-zone-off-of-steam-boiler
my preference is always for the feed into the wet return, as far upstream as possible.
i would know about thermal shock, but would a house-sitter, or an auto/over-feed?--nbc
oooh professor Dan, the math problems are getting harder!

It's a rental...

... and it has an auto-feed, so I can definitely see erring on the side of caution when it come to thermal shock.  Also, the piping is almost a century old and the wet returns just now need to be replaced, so worry about the impact of oxygenated water seems to be less than the worry about thermal shock.

Answer.

1. Use hot water to feed the boiler. 
2. End all worries.

I always feed on the boiler side

Reason is it keeps oxygen rich water in boiler to be boiled and not sitting in the return to corrode the piping.

I def. see your point...

... but I still struggle with *where* I could put the water feed on my system.  My only available locations are *really* close to the boiler and that makes me really nervous.  Barring a complete repipe that will give me some distance, are the two locations noted in the picture even viable?

No Hot Water

You never feed a boiler with hot water.  It will scale up your water feeder if you use one. 

Here in NYC, the feed, by Code has to be a certain distance from the boiler, which usually means we feed the make up water into the wet return on the return side of the loop. 

But I like Charlie's logic and think that's a better way.  It also allows you to feed water if you steam the boiler to clean it while wasting the condensate out of the returns.