Pumps vs Zone Valves


Old 09-14-12, 05:55 AM
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Pumps vs Zone Valves

I am building a new house and need to decide between ZONE PUPMS and ZONE VALVES for my heating system. The house will have a total of 9 zones (see attached diagram and floor plan:
https://docs.google.com/open?id=0B66...0hCSHpPYWdMd1U ).
Zones: 1, 2, 6, and 9 will be RADIANT HEAT.
Zones: 3, 4, 5, 7, and 8 will be ALUMINUM RADIATORS.

I spoke to several contractors and getting conflicting opinions: some advocate 9 pumps, others say it is a waste and advise only 1-2 pumps...

Can you guys offer some insight on the preferred solution, as well as pro/cons.

Thanks a lot!

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Old 09-14-12, 07:28 AM
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I believe the cost difference between pumps and valves is quite large, pumps being much more expensive ($150-200 for a pump and $50-60 for a valve) Would make more sense to me to use valves and one pump. Control wiring would, more or less, be the same.

A heating pro should give better info.
Old 09-14-12, 10:46 AM
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I think a lot would depend on how the system is going to piped.

Personally, it's hard for me to see how a single pump could do everything. Your going to need more than 1 pump, IMO.

On the other hand, it's also hard for me to understand why 9 separate pumps would be necessary, or advisable.

But I'm not a pro, either.
Old 09-14-12, 02:59 PM
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i have 3 zones, orig. with valves and i circ pump. i retrofitted and used circ pumps for each zone b/c after looking at the cross-section of the valve, it's a significant flow restrictor and i have enough head losses in my existing heat piping as it is.

you can use either/or, or even a combination. it might depend on layout, # of floors, and the total distance of pipe in a sigle zone.
Old 09-22-12, 07:43 PM
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Probably variable speed pumps on each loop would be the most deluxe way to go. Certainly a large pile of coins though.
We have 7 zones, each of various size (like yours), and I opted for a single pump with valves. The problem with this approach is, if a short zone and a long zone open up at the same time.. the short zone will get the flow (less resistance). What we did was install balancing caps (a valve with no actuator, just an adjuster screw) on the other end's manifold to reduce the flow speed in the shorter loops. There's a calculated way to balance it, if you keep track of your pipe lengths etc.. or you can just fiddle for a few years until you find a sweet setup.
Old 09-22-12, 08:07 PM
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fiddle for a few years until you find a sweet setup.
That's pretty funny!

I been fiddlin' for a lot more than that and I STILL can't even play Old Joe Clark!
Old 09-23-12, 06:12 AM
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My company tends to use pumps over valves. Everyone has their own opinion. Due to your home having basically 4 levels I would consider using pumps over valves due to head losses on the different zones. I usually find that valves also fail more often than pumps. I don't have any data to back that up, but that is what I remember anyway. In the end it is up to you. I would recommend using a manifold on the supply and return for a nicer looking install and to use valves and purge tee's on each zone for servicing purposes.
Old 09-24-12, 06:54 AM
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9 pumps in my mechanical room would sure look impressive all lined up.

As others had said, it would depend on your pipe setup.
My 3 story house (plus basement) has 2 zones with a pump each. I will be setting up the third floor on it's own zone and the kitchen as well (both using valves). Our kitchen is much warmer then the rest of the main floor, so it wouldn't demand heat before the rest of the floor. Our third floor has a high heat lost (attic rooms) which we don't use for anything but storage right now. This zone will be turned down (~60'F range) so it too would not require water when the second floor pump is not running.

Individual pumps per zone gives you more flexability as each zone gets moving water when the demand is there. It is much more expensive and would need extra pipe work to plumb it correctly. A single pump leaves you with an expensive (large) pump, and a single point of failure. That pump goes (which they do, they are a wear part), you have no heat anywhere.

Depending on your piping is setup/going to be setup, I would suggest a hybrid setup which will give you the best control for dollar.
Old 09-25-12, 06:44 PM
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The down side of using seperate pumps is most zones will be overpumped moving too much water in each zone. Seperate zone valves will normally not require a larger pump due to only sizing the pump for the largest resistance.
Many contractors are using zone valves as it uses less electricity.
Zone valves also make zoning easier as they do not have to be in the boiler room and is less expensive to install.
I have seen a swing to pumps and back to zone valves.

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