2 supply, 2 return...old boiler

Timco

I have a job where the owner wants the 4 units to be on seperate zones, but does not want to change the boiler. Orig 1930 or so Crown, HUGE 4 section unit. It has 2 supply and 2 return taps. Should both supply and both return be piped into one supply and one return manifold? Given the size and current pipe layout, I am going direct return, no bypass, 11/4" manifolds. Now each tap serves 2 units.

Thanks,

Tim

Weezbo

if the taps they are using now are on the front return....

i think that it is better to leave it that way..here is my thought, even metal stressed a couple million times tends to like to keep doing what it has been doing...using the back tap might cause problems where none existed previously....

the reason being you might chose the colder of the two supplies for that back tap..that would not be Good sort to speak as now you will be stressing the boiler metal in ways it is not "accustomed" to and might make an older boiler have a greater tendency to leak or worse...

or if what you mean is that the taps are already in use...i probably would favor the front taps for the headder.

Brad White_9

I am with Weezbo

You would be changing a dynamic that is unknown to you. The old system was likely a gravity HW setup, probably self-balancing in it's day.

I would not recommend playing, "let's abuse the elderly". That boiler deserves better, IMHO. A decent retirement rather than an early death.

Timco

Now, One tap is serving two units, and the other tap the other two units. Same size apartments. Of course, HUGE B&G pumps on 3/4 pipe for small units with copper finn convectors, sucking from the return towards a flooded X tank with a old, stuck relief valve, and boiler running right @ 30 (so the old gauge says). It's a mess. Pics later. Thanks for the advise, but given the small units and same size, do we still think seperate manifolds?

Tim

Brad White_9

I suppose

anything you do will be an improvement. I would take good practices as far as they would economically take you. Perhaps pipe far enough away from the boiler so that eventual replacement will not require you to throw away any good new work. It could be a year or ten away.

Timco

Here's the beast. I am going with 2 supply headers and two returns, with air removal on each supply header, and the Xtank / fill assy split between the supply headers prior to the new circs. Relief will be in 3/4 tap off either riser, close to the boiler. I assumed one header would mix better, and pull evenly off the boiler, but I see where the flow is accustomed to the split design of 2 headers. Pleanty of room to swap Mr. Boiler.

T