Split-zone options

Dave_46

I am replacing a boiler and one zone is a split zone. The zone heats with cast-iron baseboard on a single loop system with mono-flow tees. The two branches of the zone are 1" and the lines to the radiators are 1/2" The current set up is installed incorectly with the two sides of the zone returning on one 1" line. The return line should be 1 1/2" to accomodate the flow from the two 1" lines. The return on the new boiler is 1 1/4". Can I change the return to 1 1/2" and then split it again to two 1" lines right before I go into the return manifold at the boiler? Or, should I just make it a single loop and move some of the mono-flo tees. The zone has about 60 feet of baseboard on it. Is this to much baseboard for this one zone?

Maine Ken

If I read this right, you have a 1" supply with 1/2" feeds to the baseboards and then return on 1". If it is working, heating comfortably then why change it?

kevin coppinger_4

what is the total load...

for the entire house? 1" can do 80,000 based on a 20* delta T. 11/4" can do 140,000...1 1/2" seems a bit overkill....kpc

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Dave_46

split-zone options

The problem is that it is not heating properly now. Because the two branches of the split-zone which are 1" return to the boiler on one 1" line there is back presure on the two supply sides of the split-zone. Apparently my question was not clear. If I change the 1" return line to 1 1/2" to accomodate the flow from the two 1" supply sides of the split-zone, can I then split the 1 1/2" return line back to two 1" lines to go back into my1 1/4" boiler return manifold?

Dave_46

The total load

The zone has about 60 feet of baseboard so the load is 34,800.

Dave_46

split-zone options

Kevin,
Only one of the zones in the house is a split-zone. The other zones are single loops. The split-zone has about 60 feet of baseboard so the load is about 36,000 btu's. I figured 1" could handle this, but wondered why they would have split the zone when they installed the system.

Bruce M.

Where and how are the monoflo tees installed?

Is the zone above the boiler. Are the monoflo tees on the supply or the return or both?

Dave_46

where the monoflo tees are installed

The Zone is above the boiler and the monoflo's are on the return side of the radiators.