Adding second hydronic loop to system

Steve Garson_2

Dumb water

Maybe I am incorrect in calling it primary secondary piping. The one loop I have already, is piped like that and works great. I am adding one more loop.



As I piped it, would all the water go to the one loop with the least resistance when that loop calls for heat...which would be the baseboard loop.



Also, how close can the diverted tees be installed? Space is tight.

Charlie from wmass

The circulator would be inside the radiant loop

pump into the mixing valve. As the water warms up the flow diverters more and more to short circuit around until it looses heat and diverters back to boiler. Just like on the manifolds that I get from Viega for radiant systems. The zone pumps will each do their own thing. Steve do not use a bull tee for the second zone. Simply tee it off the supply pipe. You can always just have me do the installation for you. If it does not work I will post what a bad job I did right here on the wall for all to see. Chris there is no boiler to protect as it is a heat exchanger the cold water will be hitting. I only cover MA from West Stockbridge to Provincetown.

CMadatMe

Let's Be Realistic

First, where do you think your going to find a pump small enough that isn't going to over pump that baseboard zone? Your main needs to be 1" piping. I'd install a Caleffi QuickSetter to set my baseboard flow rate. Look at the pump curve of a 007 and even the bumble bee. You will over pump the zone so you can forget the flow rate based on a 20 degree delta-t. You'll be closer to 10 then 20.



Since the restriction or head is highest in the radiant zone and lowest in the baseboard zone when both pumps run you are going to starve the radiant zone based on your piping diagram. You only have a 3/4" main supply feeding two zones.



Realistically your going to have to carry 5.2gpm across your main.



Baseboard Zone = 2.6gpm

Radiant Zone = 2.6gpm



Just my opinion. Those can be closely spaced tees and will work just fine. In Taco FloPro Designers its easier to use them when doing diagrams.

SWEI

Small pump

Check out the B&G ecocirc e3-4 Vario (also sold as a Laing ecocirc E1, surely just to make it confusing.)

Charlie from wmass

wait a second

Chris do you think that the heat flow will be slower for the room air across the baseboard if the water is moving too fast? The air will take the heat the same speed off the baseboard no matter the flow rate. In fact if you look the heat output of baseboard is higher for 4 gpm then it is for 1 gpm. It is on the charts for any given heat emitter. Yes we will waste electricity going to the pump as we are moving more water then we need to to heat the room.

CMadatMe

Heat Doesn't Flow

The distriubtion systems job is to move btu/hr around in a circle.The emitters job is to take its required btu/hr to heat the space at any given moment in time. It's output or what energy it takes from the distribution system continually changes.



The Heat Loss is 13,000 btu/hr and the pump is going to operate on its curve. What do we have 3' of head. How many gpm will the 007 move? The pump is going to operate on its curve and could care less about anything else. In this case around 8gpm. We both know your not cramping 8gpm through 3/4" pipe so your beating up the pump, velocity is screaming and more then likely you are moving 5gpm. So what has to change in the distribution system in order to give up the btu/hr? Ding, ding,...Delta-T.



13,000 / 5/ 500 = 5.2 degree delta-t!



So now we have a baseboard loop sucking 5gpm out of the main and 2.6gpm for the radiant. So do you still think a 3/4" main is going to carry the required flow and btu/hr when both zones call? Not a chance, radiant is going to starve piped the way he has it. Might work in Oct, Nov,Mar but come Dec,Jan,Feb it won't keep him all comfy and warm.



All just my opinion of course.

CMadatMe

Nice Kurt

That would work just fine. Could even keep the 3/4" main...Still would pipe pri/sec though..

Steve Garson_2

Primary Secondary

Chris, in your piping diagram, are the symbols for just two tees, or a specific fitting like the Taco LoadMatch TwinTee? Dan's books on primary-secondary pumping seem to indicate that just basic Tees can be used if they are spaced less than 6-inches apart.



What do you suggest?



Steve

Steve Garson_2

Reducing flow rate to Baseboard loop and 3/4-inch capacity

For reducing the flow to my baseboard loop, what is the difference between using a Caleffi QuickSetter, which obviously offers precise control versus using a partially closed ball valve? Also, I was looking at some piping charts and while 4-GPM is the norm for 3/4-inch pipe, the chart shows that the GPM capacity increases as the pipe length decreases. Using primary-secondary piping, that short 3/4-inch primary loop seems to have a capacity of 25-GPM at 12 psi. Since we may need around 6-GPM, this seems safe,



Comments?

Jean-David Beyer

difference between using a Caleffi QuickSetter, which obviously offers precise control versus using a partially closed ball valve?

I have ball valves to control the flow through five parallel radiant slab loops. They work, but are not really satisfactory.



The handle turns 90 degrees from full on to full off. If I turn one to the 45 degree position, it makes a small reduction in the flow. This works fine for my kitchen and living room, and bathroom, where they are all full on. For my bedroom, that valve is quite a way down, and for my computer room, with two large computers, I must turn it down so far the valve makes quite a noise as the water tries to squeeze through the tiny aperture that remains. Eventually, this flow will erode the ball and it will not be possible to keep the flow low enough.



It is not clear to me that the Caleffi valve is much better if very low flow is desired, though it is clearly easier to adjust, because it also uses a ball valve.



If you like Caleffi products, you may wish to examine this publication of theirs:



http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CC4QFjAA&url=http%3A%2F%2Fwww.caleffi.us%2Fen_US%2Fcaleffi%2FDetails%2FMagazines%2Fpdf%2Fidronics_8_us.pdf&ei=dc33UaHJN7i34APN8IHwDQ&usg=AFQjCNHQDl9NPCf0BV3mCeeGAkZUZO_bQA&sig2=-hfkuGAMxnMwdWmkjK5BdA&bvm=bv.49967636,d.dmg&cad=rja

Rich_49

Steve ,

Your circulator must be inside the mixed circuit . You must relocate it to the other side of the mixer.  Maybe lose 2 of the flow checks also , don't need multiples . watch your Cv .

Charlie from wmass

OVER OVER thinking

we are debating this like it is a whole house heating system. It is a hot water loop off a steam boiler. Steve I will be calling by Thursday to discuss when I can come by. It is 25 feet of baseboard.

Rickr86

System Pump & Zone Pump

In the diagram shown below, Can the system pump and zone pump be in series OR at the same elevation. What spacing should i try to maintain.

Please see the attachment