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    Adding second hydronic loop to system (54 Posts)

  • Steve Garson Steve Garson @ 9:18 PM
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    Adding second hydronic loop to system

    I want to add a second hydronic loop to add a zone to the heating system. Can I simply install a 3/4-inch tee before the circulator to feed the second circulator with flow-check?  Or do I need to create a manifold?

    Steve Garson
    Newton, MA
    Steve from Newton, MA
  • Ron Jr. Ron Jr. @ 6:37 PM
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    Is the first zone 3/4 inch ?

    Does the piping come out of the boiler in 3/4 too ?  Can you post a pic of the existing setup ? You could just add a tee before the circ but the smaller piping might limit the BTUs to the zones . Depending on how big the zones are . 
  • Steve Garson Steve Garson @ 6:51 PM
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    Photo

    The pipe from the Spirovent is 3/4-inch.  I was thinking of inserting a Tee before the circulator. The question being whether the Tee can carry the water straight through to the present loop, with the new loop as the take-off.  Or would it be better to install the Tee so that both loops were connect to the Tee and an elbow.  Present loop heats 9000 BTU with baseboard.  New loop will heat 12,000 BTU radiant loop with separate circulator and tempering valve to keep the water temp at the correct level.

    This is actually the output of a Everhot heat exchanger connected to a steam boiler.  Have confirmed that the heat exchanger has plenty of excess capacity,

    Steve
    Steve from Newton, MA
    This post was edited by an admin on July 19, 2013 6:52 PM.
  • SWEI SWEI @ 11:01 PM
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    Sketch?

    The addition of a tempering valve makes me want to see a bit more.

    thanks~ 
  • Steve Garson Steve Garson @ 11:40 AM
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    Piping Diagrams

    Attached are two piping diagrams.  One is the present configuration with a single hot water loop to a baseboard zone.  The second is the one that I am looking for feedback, which is the addition of a zone for the radiant zone, which presently, is running off a coroded Combicore (my second in nine years!)
    Steve from Newton, MA
  • Tom Tom @ 6:59 AM
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    Possible

    Steve,

    In the second pic, I would swap Mixing valve with circ so it mixes first then circulates through the tubing. But it should work other than that from what I saw when I looked.
  • Steve Garson Steve Garson @ 8:58 AM
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    The Tee

    Thanks for your insight. My final question is the configuration of the Tee that I will be installing. If I install it so that the flow is straight through to the present circulator, it is an easier plumbing job. My instinct tells me that the correct way is to install the Tee with the flow diverting to both ends of the Tee into elbows and then to the circulators.

    Does it matter? Or is my instinct correct?

    Steve
    Steve from Newton, MA
  • Charlie from wmass Charlie from wmass @ 11:05 AM
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    why split before the pump?

    use two zone valves and split after the circulator but before the mixing valve.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Steve Garson Steve Garson @ 11:23 AM
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    Using one circulator instead of two

    My concern is that the present baseboard loop is very short, as in ten feet from the circulator, with twenty feet of baseboard.  The radiant loop is fed by 35' feet of 3/4 pipe on the feed and on the return.  So I think the water would take the shortest path if both zone call for heat, with the radiant not getting much water.

    Thoughts?

    Steve
    Steve from Newton, MA
    This post was edited by an admin on July 21, 2013 11:47 AM.
  • Charlie from wmass Charlie from wmass @ 7:38 AM
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    Have you checked your required flow rates?

    and compared them to the output of the pump? I was once a pump addict. I wanted a pump for every zone. I had no faith in pump curves. The thing is why run the extra pump if one will do the work? Yes water is lazy and takes the easy route. The response time on the fin tube should have it off much of the time with the radiant doing the slow and steady. I am looking at the photo you posted and it looks easier to cut in after the circulator then before it. `Both methods will work. I am just offering a different perspective.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Rich Rich @ 5:07 PM
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    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 .
    You didn't get what you didn't pay for and it will never be what you thought it would
    This post was edited by an admin on July 30, 2013 5:13 PM.
  • Tom Tom @ 6:19 AM
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    You Got it

    Steve,

    I would say you have a good plan, the second pic with the swap of the circ and mixing valve will work fine. Piping is pretty forgiving and what you have if it's easier should work great.
  • Charlie from wmass Charlie from wmass @ 7:46 AM
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    I just found your other post in radiant heating

    that little copper coil may not like the velocity you are asking using two pumps. Also you are supplying it with heat from only one taco 007 pumping condensate, how is that going to handle the output? I am assuming from the photos you are a DIYer and you did that piping yourself right?
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Charlie from wmass Charlie from wmass @ 7:46 AM
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    I just found your other post in radiant heating

    that little copper coil may not like the velocity you are asking using two pumps. Also you are supplying it with heat from only one taco 007 pumping condensate, how is that going to handle the output? I am assuming from the photos you are a DIYer and you did that piping yourself right?
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Steve Garson Steve Garson @ 8:53 PM
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    Flow Capacity

    The Everhot RH-6 is rated at 6GPM with 35,000 BTU capacity. The GPM is based on 100* rise at 200* boiler temp.
    Steve from Newton, MA
    This post was edited by an admin on July 22, 2013 9:25 PM.
  • Chris Chris @ 8:07 AM
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    First Off

    Radiant and baseboard should have different design delta-t's. The first question is what is the required flow rate needed for the baseboard and what is the required flow rate for the radiant? Your main better be able to carry the total flow rate before you split off into that tee.

    Second, should have 12" of straight pipe before you enter those circulators.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Charlie from wmass Charlie from wmass @ 1:05 PM
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    He has a mixing valve for the radiant

    the zone valves would be teed before the mixing valve and the return for the baseboard would be after the mixing valve. That way the radiant gets radiant temps and the baseboard gets baseboard temps. It also means only low voltage wiring and no additional relays to turn on any other circulators.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Steve Garson Steve Garson @ 9:23 PM
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    Heat load on baseboard loop and radiant loop

    For the baseboard loop: 18-feet of baseboard with a heat-loss of 13,000 BTU. This room takes almost no time to warm up after a call for heat.

    The radiant loop has 13,000 BTU of heat loss and four loops of Onyx under the floors
    Steve from Newton, MA
    This post was edited by an admin on July 22, 2013 9:24 PM.
  • Steve Garson Steve Garson @ 11:05 PM
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    Flow rate and BTU

    Btu/hr Q = GPM x 500 x Delta-Temp

    26,000 BTU = GPM x 500 x 20* = GPM x 10000

    GPM = 26,000/10,000 = 2.6 GPM

    Everhot RH6 Specs: 35,000 BTU at 6GPM

    Delta-Temp = 35,000/(6GPM x 500) = 11.66 delta temp

    5GPM gives a 14* delta temp

    4GPM gives a 16.5* delta temp

    I'm not sure where this is going, since the Everhot specs say there is a 100* rise with 200* water.
    Steve from Newton, MA
  • Chris Chris @ 5:59 AM
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    Disagree

    With your flow rate. Formula is correct for a 20 degree delta-t but that radiant should be running on a 10 not a 20.

    Baseboard Flow = 1.3gpm
    Radiant Flow = 2.6gpm
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Zman Zman @ 7:50 AM
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    Gpm

    Chris is correct. Your radiant will pull a little less if you are mixing. Either way you are under the 4 gpm your 3/4" pipe can handle. In a perfect world you would pipe this reverse/return or increase your header size for a design of 2 fps. I think it will work as you are planning. You will have trouble finding a circ that will go down low enough for you baseboard loop, you might consider a balancing valve.
    The circ on your mixing loop needs to be in the mixing loop. The way you have drawn it, the circ will dead head as soon as the loop comes up to temp. All circulation will stop.
    As Chris mentioned, do not put 90's and tees near the inlet side of the circs. I think the rule is 12 pipe diameters. In your case that would be 9".
    Don't worry about the 100 degree rise from everhot. That is just the number they are using for their gpm calcs. Gpm x delta t x 500 =btu/hrs will alway be the formula. They are basing their gpm on a delta t of 100 . This is for dhw production.. Your design will be different since you are using it for heating.
    Happy piping,
    Carl
  • Charlie from wmass Charlie from wmass @ 8:35 AM
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    Thanks guys I missed the mistake in the drawing

    the circulator is on the wrong side of the mixing valve for the radiant zone. It needs to be inside the radiant side of the loop. Then of course you would need to use two circulators. I was thinking since it was such a small zone you were using a manual mixing valve to roughly set the temp in the radiant zone, since it is an automatic valve the circulator needs to be moved.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Steve Garson Steve Garson @ 6:59 PM
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    Circulator location

    Are you suggesting that the circulator for the radiant should be to the right of the of the mixing valve on my drawing?
    Steve from Newton, MA
  • Chris Chris @ 7:09 PM
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    May I Suggest

    The attached for some reading. Should answer all your questions.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Steve Garson Steve Garson @ 7:35 PM
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    Circulator location

    Chris:

    Interesting reading.  Everything I've learned has the circulator located right after the expansion tank & air eliminator.  Is locating it as described in that PDF, downstream from the mixing valve flow, the normal and customary design approach?  Or this this  subject with much debate?

    Steve
    Steve from Newton, MA
    This post was edited by an admin on July 23, 2013 7:38 PM.
  • Chris Chris @ 7:40 PM
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    There Is Zero Debate

    That the radiant supply circulator must be installed after the mixing valve. The question is, do you need to provide boiler protection from low water temps, ie, less then 140 for a cast iron boiler? If so, then your piping approach should be primary/secondary.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
    This post was edited by an admin on July 23, 2013 7:43 PM.
  • Steve Garson Steve Garson @ 7:48 PM
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    Piping Approach

    Yes, this is primary-secondary piping.  No radiant water is getting to the boiler .I checked the instructions for the Taco mixing valve and see that you are 100% correct.  I am fixing work done by a "pro" who did not install the circulator and mixing valve as you describe. 

    I think I finally have all the info I need.  Thanks for catching that error.  I will post a new piping diagram with the final design.  I'm actually going to use a plumber. I've just learned that there are plenty of people who don't truly know what they don't know.

    Steve
    Steve from Newton, MA
  • Zman Zman @ 8:10 AM
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    EDR

    Steve,
    I looks like you are on the right track. Chris makes a good point about making sure you are protecting the boiler from condensation. Has anyone compared your steam radiator EDR values to the size of you boiler. In other words, does your boiler have enough capacity to service your existing steam system and your new system?
    Carl
  • Steve Garson Steve Garson @ 11:25 AM
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    Final Piping Design

    Attached is the final piping design, based on all the generous pros who have offered their insight.  My boiler, a WG SGO-4 with a Carlin EZ-Gas has plenty of capacity,  On a design day in the cold of the winter, it runs no more than 20% of the time.  Our house is very well insulated and sealed from air leaks.  The boiler size is based on steam radiator EDR, from the days of no insulation and leaky windows.

    If anyone has any more suggestions, I would love it.

    Steve
    Steve from Newton, MA
    This post was edited by an admin on July 24, 2013 11:40 AM.
  • Chris Chris @ 11:56 AM
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    Won't work

    Need a another pump and the piping is wrong.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • SWEI SWEI @ 12:32 PM
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    Plenty of capacity

    How much, in relation to your design-day heat loss?

    And I don't think I'm 100% clear -- this is purely a hot water system with no steam?
    This post was edited by an admin on July 24, 2013 12:35 PM.
  • Steve Garson Steve Garson @ 2:30 PM
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    Heat Loss and Another Circulator?

    Chris, The drawing does not display the circulator that feeds the hot water from the steam boiler to the heat exchanger, since that is already installed.  Do I need another?  if so, where?

    For heat loss, the building heat loss is 75,000 BTU.  The boiler is steam; WM SGO-4, with a steam rating of 108 MBH and DOE heating capacity of 144MBH.  The steam radiators have a total of 461 square feet of radiation.
    Steve from Newton, MA
  • Chris Chris @ 5:12 PM
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    See Attached

    This is how I would pipe it.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
    This post was edited by an admin on July 24, 2013 5:17 PM.
  • Tom Tom @ 6:41 PM
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    My bad

    Steve,

    Chris is right I didn't notice it was an everhot heat exchanger when I told you that it would work, I assumed the circle was a boiler with a built in circulator, my bad. His diagram is probably the best design not the cheap and easy way but will work without fail and be the least problematic.
  • Steve Garson Steve Garson @ 9:48 PM
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    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 from Newton, MA
  • Charlie from wmass Charlie from wmass @ 9:41 PM
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    For the size of system you have

    I do not see why your newest diagram would not work. I just would suggest changing the circulator for the steam side to a B&G 100 Bronze.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Chris Chris @ 9:45 PM
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    How Would He Get Flow

    To the secondary loops his way? He specifically said he was primary/secondary piping.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
    This post was edited by an admin on July 24, 2013 9:46 PM.
  • Charlie from wmass Charlie from wmass @ 9:52 PM
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    it is not primary secondary if you look at his other posts

    He is using the everhot as a heatexchanger. He has a high temp loop and a low temp loop. He is using a taco 007 to push the water from the steam boiler through the everhot. He is piping the hot water loops off the side that would be the domestic coil.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Charlie from wmass Charlie from wmass @ 9:55 PM
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    I would usually put the mixing valve

    and the circulator on the return from the radiant loops with the circulator pushing into the mixing valve.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Chris Chris @ 10:05 PM
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    Huh?

    Why would water move through the cold water side of the mix valve and give you the proper water temp? Pondering the flow through my mind and all that return water would beat feat for the boiler. It has no reason to go North..
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Chris Chris @ 9:59 PM
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    Exactly

    It has a coil in it. The pump from the steam boiler is only moving btu/ht to the tank. Need one to take it away. The way he has is piped water would never leave it.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Steve Garson Steve Garson @ 6:29 AM
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    Diverter Tee Approach

    Chris,

    Just so I can understand, why would BTUs not leave the Everhot with my piping diagram pulling water from the Everhot? There are two circulators that I thought would take the BTUs away, one for each zone. I'm not challenging your design, but interested in understanding the reason. By the way, I appreciate the time you've given me on this project. This thread has become an interesting one in many ways. Do you have a preferred brand of diverter tees?

    Steve
    Steve from Newton, MA
    This post was edited by an admin on July 25, 2013 6:30 AM.
  • Chris Chris @ 6:46 AM
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    Pri/Sec

    You specifically stated that you were pri/sec
    piping. Your diagram is not proper pri/sec
    piping. Water is dumb when both zones call,
    where do you think all the flow is going to go
    piped as you have it?
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Steve Garson Steve Garson @ 6:57 AM
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    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.
    Steve from Newton, MA
    This post was edited by an admin on July 25, 2013 7:00 AM.
  • Charlie from wmass Charlie from wmass @ 7:46 AM
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    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.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Chris Chris @ 7:57 AM
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    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.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
    This post was edited by an admin on July 25, 2013 7:58 AM.
  • SWEI SWEI @ 11:36 AM
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    Small pump

    Check out the B&G ecocirc e3-4 Vario (also sold as a Laing ecocirc E1, surely just to make it confusing.)
  • Chris Chris @ 12:51 PM
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    Nice Kurt

    That would work just fine. Could even keep the 3/4" main...Still would pipe pri/sec though..
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Charlie from wmass Charlie from wmass @ 12:16 PM
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    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.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Chris Chris @ 12:46 PM
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    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.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
    This post was edited by an admin on July 25, 2013 12:58 PM.
  • Steve Garson Steve Garson @ 8:29 AM
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    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?
    Steve from Newton, MA
  • Jean-David Beyer Jean-David Beyer @ 11:03 AM
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    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
  • Charlie from wmass Charlie from wmass @ 10:54 PM
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    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.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • Rickr86 Rickr86 @ 2:49 PM
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    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
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