can I add a zone like this?

heatingFun

Please refer to this diagram (attached or this link) to see my existing piping and my plan to add a new zone:



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We converted from oil to gas last year and now we are thinking add two rooms into the system as a separated zone. It is a hot water heating system.



Please tell me "Option 1" is valid or not? if not, how about "Option 2"?



thanks,

Charlie from wmass

2 not one

lots of other ways too. are TRVs used on one?

heatingFun

a better way?

can you tell me one of them, which you think is better and simpler? thanks

Dave in QCA

Use Option 2

The problem with the first option.  If the new zone was running, and the original zone was not, you would likely set up some strange back flow patterns in the 2 original rooms closest to the boiler.  The water doesn't know where it is supposed to go, and any time there is even a very minor pressure difference, it will flow.  Water flow passing through a tee fitting is enough to draw water from the side branch of the tee, and cause unintended circulation.  ( am speaking from real experience)

Option 2 should work great.

hot_rod

what type of boiler?

cast iron, copper tube, mod con? You may not need that pump at the boiler?



As drawn it is not primary/ secondary, if you have a mod con boiler, that may be suggested.



One pump and zone valves could be another "energy saving" option.



hr

Tony Massi

Zoning

Use option 2.  I don't know why you would use a circulator on the return when you have one on the supply.

heatingFun

mod cond boiler

yes, the boiler is a mod cond gas boiler from Burnham.

heatingFun

recommended by boiler manufacturer

that circulator is suggested by the boiler provider. the boiler is Burnham Alpine gas boiler: http://www.usboiler.burnham.com/products/residential-boilers-indirect-water-heaters/alpine

Jean-David Beyer

Primary|secondary?

I imagine the boiler wants to see a primary|secondary near-boiler piping setup. Hence the circulator up next to the boiler. The connection between supply and return that comes next and the related Ts are almost certainly supposed to be the closely spaced Ts of the primary|secondary setup. (You could use a low-loss header there instead if it comes out cost effective.) After that you need at least one circulator in the secondary side.



On the secondary side, either the heat emitters are precisely what the user wants, or there are balancing valves in there that are not shown. Also a flow check valve in each zone to prevent accidental flow through a zone where the circulator is not running?



Options 1 and two seem almost the same to me (a non-professional), but Option 1 would be more difficult to analyze and seems to present no advantages. Option 2 seems the way to go. Also, in all three diagrams, why is the supply directly connected to the return at the end (away from the boiler) of each zone?



However, has others have pointed out, you could probably save energy by using one circulator in the secondary side and zone with zone valves. If you do that, you would probably be wise to use an ECM motor in the circulator because otherwise you would probably need a differential bypass valve and that would be inefficient.