New zone

Don_183

Hello,I currently have a one zone,forced hot water baseboard system with 3/4" copper pipe in my ranch home.I am adding heat to two small rooms in the basement.I want to add two 8' baseboards with 1/2" PEX pipe. My plan is to use two zone valves and the one original circulator pump.The area to heat is small and well insulated.Does this sound OK or do any problems stick out? Do I still need backflow preventer's. Any help would be appreciated.

Brad White_125

Seems like a reasonable approach

But I would start by asking yourself some of questions:

1) Does the house heat well now? Is the boiler amply sized, perhaps installed pre-insulation and now with some surplus to spend? (Granted it seems to be a modest load but I have to ask.)

2) Will the existing pump handle the flow rates required of both zones? It seems resonable to assume so given that your 16 feet of baseboard will emit about 8-10,000 BTUH so will take 0.8 to 1.0 GPM, while the 3/4" main zone may well take 4.0 GPM.

My guess is a circulator such as the Ubiquitous Taco 007 may welcome having another path to take...

When you say "backflow preventers" do you mean "flow-check valves"? So long as the control valves hold, I do not see an issue if you do not have them.

Here is another thought/question:

Is it your intent to have the small zone also have the authority to start the pump and boiler independently of the main house? If so, I would strongly recommend a pressure relief bypass valve (Macon, Honeywell D-146, Oventrop and others) to let the excess flow have a path back to the boiler. With one small zone calling you will get noise I strongly suspect.

My recommendation would be to install a high limit TRV on the smaller zone as a slave to the main zone. The assumption is that you would be heating the main house zone anyway and this would be slaved to it. Just a thought.