Zoned Heating Piping Correct?

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When there are two thermostats as there should be for two zone valves, once a zone is heated to the set temperature the respective solenoid valve would close. Why the need to balance? Would that be primarily when there is only one thermostat?
 
What if both zones are open at the same time and you want an even distribution?
 
I agree what the heck does that even mean there's no need for balancing

thermostat one calls for heat zone valve one opens and continues to stay open until thermostat one is satisfied. I have five zones in my house each one of those owns has a thermostat my bedroom can be 85° my kitchen can be 62° it's all what I set the thermostat at
 
balancing gives you higher efficiency
radiant heating works by the heat transfer from the pipe to the fins
or tubes.
if the water is to fast the efficiency of the system is lacking. and you could have areas that will not heat
//can not heat.
if you slow the water down, it allows the heat to radiate
balancing is mainly done on commercial jobs
it works,
why did i suggest balancing?
if the stat is working
if the unit is not air locked
if no windows are knocked out/ room is tight
you should have heat, if you do not
the question is, is the water moving to fast for the heat to radiate to the living space.
slow the flow and the heat in the room increases.
 
Why modulating?
True you can get more efficiency using different approaches, like outdoor reset, for one.
Don't think he wants to redesign the system any more than he has to.
I think we should assume...
a working thermostat.
The system is not air locked.
no windows are knocked out.
Tightening up a room for heat loss is always an option.
Since the first floor is a shorter loop flow should be faster than the other floor.
As you already stated, the second floor always tends to get hotter.

Just briefly...," baseboard will put out pretty similar outputs over a very broad range of flow rates."

Now why would a landlord want to have control of the heat in the tenants apartment, as currently set up?
 
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baseboard will put out pretty similar outputs over a very broad range of flow rates. You have to really slow down the flow to see a decrease in output, which leads to problem #2 - when you slow down the water that much, the water will get too cool by the time it gets to the end of the loop to put out adequate heat. So the first room on the loop will see full temperature water and put out full heat, the next room will see slightly cooler water, and put out less heat. This room will have a lower temperature. The next room will get even cooler water, and so on until you get to the last room (if it is a long enough loop) that doesn't get heat at all.

A far better way to to even out the system is to keep the flow rates the same, but change the water temperature flowing though the system based on the outdoor temperature - known as outdoor reset. A structure only needs the maximum water temperature during the coldest day of the winter. On more temperate days, the water does not need to be so high. The boiler will operate more efficiently with lower temperature water especially with a mod/con boiler. (Don't go too low with a non-condensing boiler though - keep around 140° return. On a non-condensing boiler, you need to install a mixing valve to get lower system loop temperatures). If the reset curve is set aggressive enough, the system will basically be in constant flow. The output of the baseboard will match the heat loss of each room which will provide a very even and comfortable heat.

what are the ''broad range of flow rates discussed?

flow_rate.png

flow_rate1_001.png
 
frodo, you'll have to excuse me, but I've seen much of the stuff you're showing here. I don't disagree with it but it getting too far off the problem and simple solution.
 
It doesn't matter if the water's moving one foot per hour or thousand billion feet per hour the hot water is still going to be circulating through the baseboard giving off heat. As long as that thermostat is calling for heat they'll be hot water in that baseboard...
 

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