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Bottleneck in the hydronics that was installed along with my new heat pump?

Gerg
Gerg Member Posts: 15
The hydronics is a 2 pipe reverse return. I feel like the design is bad but I don't have enough knowledge to express my concerns. The heated water leaves the heat pump in 1.25 inch copper then at the manifold at each zone valve (there are 3) the copper is reduced to 3/4 inch and then on to the basement and radiators in the house. The contractor originally installed 3/4 inch all the way to the radiators, but when water would not circulate he changed out the 3/4 inch pex in the basement with 1 inch copper. Water flow improved, but he left the section from the manifold through to the basement as 3/4 inch copper. This creates a bottle neck on the send and return of each zone. Will this reduce the efficiency of my system? Is this cause a problem big enough to raise a complaint?

Comments

  • Ironman
    Ironman Member Posts: 7,367
    edited March 2015
    We really need more info as pipe sizing is based upon the required gpm and that is based upon the amount of btus required for that line. Then, there's the size of the circulator and its pump curve which will determine how many gpm it will produce based upon the head (resistance) of the circuit.

    Can you tell us the btu requirement for each circuit as well as the total? The make and model of the circulator? What type of emitters? Approximate length of each circuit?

    To generalize, a 3/4" line will carry 4 gpm; a 1" line will carry 8 gpm; and a 1.25" line will carry 14 gpm. That's at about 4 feet per second which is the maximum velocity for normal hydronics. The zone valves also add resistance (head) which must be calculated.

    Some pics would be helpful too.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Gerg
    Gerg Member Posts: 15
    Thanks. I will have to go through my papers and take some measurements to answer all those questions. I'll get back to you as soon as I can
  • Gerg
    Gerg Member Posts: 15
    Hello, I think I am continuing this discussion with Ironman, but I am new to the blog format so I am not sure how this works. I am including a schematic of the system which is installed. Numbers show length of runs or length of radiators. The average PEX run is 10 feet per length. I don't have BTU data, but it is an 1800 square foot house with a 5 star energy rating. My worries are that the reduction to 3/4 inch copper after the manifold and before the 1 inch copper pipe will reduce the efficiency of the system. Also I worry about zone 1 with no 1 inch copper and the places where the PEX leaves the main feed as one pipe and then splits to 2 for the radiators. All these areas look like bad design to me. What do you think?
  • icesailor
    icesailor Member Posts: 7,265
    One thing about Hydronics. You really have to work at it to really screw it up.

    Bigger pumps will solve most wrongs all situations.

    Is it neat? Post a Photo.
  • Gerg
    Gerg Member Posts: 15
    To a laymen's eye, the work passes the neatness test. After the copper passes through the wall into the crawl space, it enlarges from 3/4" to 1".
  • Gerg
    Gerg Member Posts: 15
    When you say "One thing about Hydronics. You really have to work at it to really screw it up." are you saying the diagram I posted shows a screwed up design or that even with its inconsistencies the design does not screw up its function?
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,455
    I think he (ICE) was trying to say if the system looks sloppy then it was probably a poor install. Neat workmanship shows the installers pride. If the job looks good the installer simply may be experienced with pipe fitting but not necessarly with design. If it looks sloppy then the whole thing may be wrong.

    If you can post the sizes and types of heat emiters (baseboard, radiators, wall radiators etc) we can find the btu requirements which will decide the flow rate required.

    1. Type of boiler and BTU OUTPUT
    2. # of zones and # and size of heat emmiters.
    3. If we do just one zone for starters we can probably find out what is going on.
    4. Pipe size at manifold connections

    BTU load of house is used to size boiler.
    BTU load of each room determines size and # of radiation in each room.
    Btu of radiation on one zone is added together. Depending on style of boiler temperature drop of water is determined.
    TD could be 20 deg water will transfer 10,000btu/gpm circulated
    TD could be 30 deg water will transfer 15,000btu/gpm circulated

    Gpm circulated determines pipe size. 1/2"=1.5 gpm=15,000 btu @20 deg. td, 3/4"= 4.5 gpm=45,000 btu@20 deg td, 1"= 8gpm=80,000btu@ 20 deg td.
    Gerg
  • Ironman
    Ironman Member Posts: 7,367
    edited March 2015
    Based upon your diagram, everything looks okay. Again, without knowing btu requirements, sizing can't be confirmed.

    Is the Bumble Bee circ held off when all zone valves are closed? I would have gone with a delta P circ like the Grundfos Alpha, but if the circ is wired so that a zone valve must open before it energizes, then the design is acceptable.

    Is there another circ in the system?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    Gerg
  • icesailor
    icesailor Member Posts: 7,265
    edited March 2015
    Gerg said:

    When you say "One thing about Hydronics. You really have to work at it to really screw it up." are you saying the diagram I posted shows a screwed up design or that even with its inconsistencies the design does not screw up its function?

    No. What I was saying is that you really have to make some blatant mistakes to screw it up enough to have it not work totally. Its hard to draw something as it is installed. That a photograph will show exactly. Judging by the quality of the installation you have, the installer should post that on the HVAC-Talk "Wall of Fame". That job is exceptional.

    Gerg
  • Gerg
    Gerg Member Posts: 15
    Thanks to all who have weighed in. To continue my investigation, here are some answers to the questions you have asked.
    For Ironman....There is only one circ pump, the bumblebee, and yes it does only come on when a zone valve opens.
    for Ebebratt...1) The heat source is a Daiken air source heat pump. 2) Three zones plus a domestic hot water heater. The emitters are Smith's heating edge perimeter baseboard style. Zone 1 has a total of 35' of emitters. Zone 2 has 31'. Zone 3 has 20'. 3) The pipe size at the manifold connection is 3/4". The temperature drop across the send and return at the manifold approx. 8 degrees. I have a difficult time using the pipe size information because each zone comes from a 1-1/4" manifold, down to a 3/4 section with the zone valve and then a 1' section in the crawl space and then 3/4 inch PEX out to the emitters. (see attached diagram) Understanding the effect of so many different pipe sizes has me confused.
  • Ironman
    Ironman Member Posts: 7,367
    Is there an internal circ in the hydro box? If not, the BumbleBee will not create circulation through it since it's hydraulicly separated by the closely spaced Tees.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    icesailor
  • Gerg
    Gerg Member Posts: 15
    Yes, there is a circ pump in the hydrobox. Also, I know I am getting circulation in the system because the emitters heat up. My concern is that the system is significantly less efficient because of the 3/4" pipe between the 1-1/4" manifold and the 1" pipe in the crawlspace. I am sure this reduces the amount of flow and makes the circ pump work harder so that has to use more energy. Does the reduced flow make the heat transfer less efficient too? Efficient energy use is my goal.
    Here is some information that may be useful......
    The temperature drop between the in and out manifolds is about 8 degrees. 128 degrees going out and 108 degrees coming back. The temperature drop between the in and out of each emitters varies from .5 to 10 degrees, but the average is 4 degrees. The temperature drop between ins and outs at the emitters is very inconsistent, almost random and doesn't appear correlated to the emitters length. thanks..........

  • Gerg
    Gerg Member Posts: 15
    Hello everyone. I think my questions boil down to this: How can I determine that my hydronic system is operating the best that it can? Can I do this by analyzing the design? Can I do this by taking temperatures or temperature differences at the manifold or emitters? If the hydronics are not optimum, what can I do to make it optimum. As I said before, energy efficiency is my goal.
  • Ironman
    Ironman Member Posts: 7,367
    Are you having issues with any of the zones heating properly? Is the BumbleBee set to the delta T mode? If so, then the circ needs to be set to a fixed speed.

    Water takes the path of least resistance and if both of the larger zones are calling, then the one with the least amount of piping is going to get more flow. This can cause the circ to sense its target delta T from the greater flow in the shorter zone, begin to slow down and thus starve the longer zone for flow. That's why I made the statement earlier that a delta P circ like the Alpha would have been a better choice for this application. To make a delta T circ like the Bumblebee work with your design requires near equal resistance in each circuit. That would necessitate near equal length and/or balancing valves.

    I don't see the 4' lengths of 3/4" causing major issues or adding any significant energy useage to the circ ( its maximum wattage is only 42w).

    Again, pipe sizing is based upon btu requirement and a 3/4" line can deliver 40k btus @ a 20* delta T and and 20k btus @ a 10* delta T.

    If memory serves me correctly, the AllTherma is a 4ton (48k btu) unit. That would mean that three 3/4" x 100' loops would be sufficient to carry 20k btus each @ a 10* delta T for a total of 60k btus. That's more than the capacity of your heat pump. The 8' of 3/4" pipe in your larger zones is not gonna cause any issue. There's far more resistance in your zone valves than those sections of pipe.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    Gerg
  • Gerg
    Gerg Member Posts: 15
    After some experimenting with variable speed, the contractor set the bumblebee constant speed. Thanks for your explanation. From your explanation of of pipe size and delta T, it seems like I could get a realistic picture of how well my system is working by measuring the delta T at the in/out of each emitter. Or by measuring the delta T at the in/out of the manifold. Is that the case? Would you comment on this idea?
  • icesailor
    icesailor Member Posts: 7,265
    Years ago, Taco sold drilled and tapped circulator flanges. They were drilled and tapped 1/8" NPT.

    I thought that if you put a 0# to 30# pressure gauge on the inlet and outlet of the pump, you could take the pressure differential when running, and the static pressure when it wasn't running, and come up with the differential pressure. Then, look on the pump curve for the installed pump. Look at the place on the curve tells you the GPM being pumped. Checking the temperature going in to the zone, and out of the zone, got you pretty close to the BTU's being used by the zone.

    Isn't that how the professional circuit setters do it?

    How nice it would be if we had tapped flanges today. Something to look forward to in the future. Short Bus circuit setters.
  • Rich_49
    Rich_49 Member Posts: 2,766
    Gerg, Were these heating edge baseboards designed to take advantage of the higher output ?

    I notice that 3 of them have only one pipe used while the other 8 utilize parallel feeds . Yo get the output from the parallel pipes that is listed you must guarantee a minimum 1.5 gpm flow through each . # 1 requires 7.5 gpm , # 2 -5.5 gpm , # 3 -2 gpm . The head of each circuit may be an issue , the Bumble Bee , if # 1 manifold is calling would require 7.5 gpm , pump curve would suggest that this flow can only be achieved at less than 7.5 feet of head .

    This compounded with what others have stated may be your entire problem . If # 1 is the only manifold being fed you run into problems with Bumble Bee . Where are you located ? I would suggest changing out that circulator for something with a bit more **** . Maybe your contractor will figure out what the exact head for that longer circuit is and the total flow at design and get the right pump in there for you .

    http://www.taco-hvac.com/uploads/FileLibrary/102-435.pdf
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
    Gerg
  • SWEI
    SWEI Member Posts: 7,356
    icesailor said:

    How nice it would be if we had tapped flanges today. Something to look forward to in the future. Short Bus circuit setters.

    You can still get them with pressure taps, but ball drains with hose bibbs (which we're already installing in most cases) will work. I have 3/4" MGHT adapters on my differential pressure gauge.
    Gerg
  • icesailor
    icesailor Member Posts: 7,265
    These were standard Taco flanges that were tapped into the pump space. Nothing fancy or special. They had to be making them in 1982 because that's when the job was done.

    I looked them up once and they only offered them for 11* series 3 piece circulators. They didn't offer them for 0** circulators even though they were the same flanges.

    The job also had 1600 circulators. They had gauge ports too. I wish I had photos.

    What was interesting was that the circuit setters were marked with GPM flow and locked down. The pressure differential on the gauges corresponded to the pressure/GPM on the 112 Circulators.
    Gerg
  • Gerg
    Gerg Member Posts: 15
    Rich, I was told by my contractor that these higher output baseboards were needed for the lower output heat of a heat pump. I think that 3 baseboards only got one feed from the main branch because it was more physically more convenient to install it that way. Thanks for your input on head and flow, there is a lot there to think about. I will have to do a little more homework to put the information to use.
  • Ironman
    Ironman Member Posts: 7,367
    Your only gonna get a little over half the Heating Edge's output using one pipe. If you put a U bend on the end so that the tubes are in series, you'll get about 3/4 of its full capacity. There are four different ways to pipe the rads and Smiths give you a different output for each configuration. As Rich pointed out, there's also a minimum gpm to achieve the rating.

    Another thing to understand about the output of rads is the delta T between the room air temp and the water temp in the rad: the higher the differential, the higher the output. If someone used the output numbers for 180* supply water temp and the AllTherma can only supply 120*, then the output is gonna obviously be much lower.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    Gerg
  • Gerg
    Gerg Member Posts: 15
    Hello, I'm back. Thanks to everyone who has helped me to understand hydronics better. For the last week I have been researching and reading and trying to understand for myself if my system could be made to work better. This has been interesting, difficult and frustrating but above all, it misses the point.

    I hired a contractor to install a brand new, from the bottom up, heat pump and hydronic system in my house. I paid a pretty penny and understood that everything would be done to get the most energy efficient system possible, including : A Daiken altherma air source heat pump. All new pipes with a first in last out, reverse return design. Taco variable speed pump. New Heating Edge emmitters. When it was done, it simply did not work. No water to the emitters.

    Okay, after a number of revisions in the hydronics system, it does work, in as much as the emitters do get hot. But how do I know it is working to the best of its capability? The contractor has not inspired my confidence in his design abilities.

    There are 2 design problems that I see as degrading the efficiency of the system.
    1) The ¾ inch pipe and zone valves located between the 1 ¼ inch manifold and the 1 inch copper main feeds. Thus causing an unnecessary resistance to flow rate.
    2) The emitters that are fed with only one length of ¾ inch pex instead of two, as the most efficient design calls for.

    The contractor has been responsible getting the system to work. He is a nice guy. I don’t want to cause him unnecessary grief. But, I did pay for what I thought was a “ best standards and practices” type installation. Does anyone see my 2 problems as listed above to be worth fixing? Would fixing those 2 problems result in any improvement or am I just being an overly fussy homeowner?

    Please see the attached schematic of the system to help answer any of your questions.
  • Ironman
    Ironman Member Posts: 7,367
    The real question is: does the system heat every area of your house properly?

    As far as your two concerns go:
    1. I don't see the 3/4" line as an issue; and, if you remove the zone valves, how would you propose to provide zoning? Again, the issue is the lack of pump capacity for the design.
    2. If the areas that have only one tube connected are heating correctly, then do they really need the second tube connected? To do so may rob other areas of btus when multiple zones are calling.

    I know we've stated this before, but without any heat loss numbers, nobody's gonna be able to say exactly what's right or wrong with your system.

    Again, if it's heating correctly, give your contractor a break and let him move on. I'm sure he's lost his shirt on this one.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    Gerg
  • Gerg
    Gerg Member Posts: 15
    Hello Ironman, Thanks for your assistance. I will take to heart your advice about the 3/4" pipe and the single pipe on the emitters, but just to answer your question, I would not get rid of the zone valves, I would just replace them with 1 inch diameter valves if I were to replace the 3/4 " pipe with 1" pipe.

    I do have a question though. What are "heat loss numbers" and how can do I determine them?

    This blog has improved understanding of hydronics and that makes it easier let go of my concerns. Thanks
  • Rich_49
    Rich_49 Member Posts: 2,766
    Heat loss numbers are the numbers able to be viewed or known after having performed a room by room heat loss calculation . This will determine the BTUh required to replace the heat lost in that room . This enables one to determine how much emitter , what SWT , flows and piping configuration that is best for each area . The fcat that you are asking what these are would suggest that one was not performed for your home . This also brings up the next questions , How were the emitters sized for each room and how was the boiler size determined .

    ALL HEATING PROJECTS THAT ARE PROPERLY DONE START WITH A ROOM ? ROOM HEAT LOSS . PERIOD .....
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
    IronmanSWEI
  • Ironman
    Ironman Member Posts: 7,367
    Rich said:

    Heat loss numbers are the numbers able to be viewed or known after having performed a room by room heat loss calculation . This will determine the BTUh required to replace the heat lost in that room . This enables one to determine how much emitter , what SWT , flows and piping configuration that is best for each area . The fcat that you are asking what these are would suggest that one was not performed for your home . This also brings up the next questions , How were the emitters sized for each room and how was the boiler size determined .

    ALL HEATING PROJECTS THAT ARE PROPERLY DONE START WITH A ROOM ? ROOM HEAT LOSS . PERIOD .....

    I could not have said it any better.

    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • kcopp
    kcopp Member Posts: 4,419
    I know I am late to the conversation.... It there any volume to this system? AKA a Buffer tank?
  • NRT_Rob
    NRT_Rob Member Posts: 1,013
    I will second the idea that 3x 3/4" pipes is more than enough to move the full output of this heat pump. Non-issue. I don't see any red flags in the pipe layout either.

    I'll second Kcopp's question about the buffer tank, just because you do need one with that heat source, about 5 gallons is all you need on the primary loop. But that is mostly about defrost with this unit, also not otherwise an efficiency or capacity issue. with ENOUGH 1.25" pipe you might have 5 gallons in there...

    I do see one red flag in your comments though. You said the unit was putting out 128 degrees at a time that I do not believe it was very cold outside. With any altherma, that is not a sustainable water temperature throughout a winter unless you're in the deep south or some other extremely moderate climate.

    If you actually need that water temperature to provide heat when it's not that cold out, then the system will not be able to keep up with demand when it is cold out. However, you may be in "setpoint mode". When you look at the altherma, you should see an A with a box of arrows around it: that means you're in "outdoor reset mode" which is, on a system like this, a must-have. If you don't, it's just providing a fixed temperature.

    Everything else appears to be in order so far. If you're maintaining room temperatures then I'd say in concept you're doing ok. I would just look at reset and the water temps and make sure the unit is running in "reset mode" with an appropriate temperature curve. Hopefully your contractors knows what your design water temperature should be.
    Rob Brown
    Designer for Rockport Mechanical
    in beautiful Rockport Maine.
  • Rich_49
    Rich_49 Member Posts: 2,766
    Rob, where have you been ? Have not seen you here or anywhere for quite awhile .
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
  • NRT_Rob
    NRT_Rob Member Posts: 1,013
    NRT had an ugly and protracted demise, so I've been adjusting to a new life. It's taken awhile to find my feet again. Feeling a bit back to my old self these days though, and it feels good. Working with a great mechanical company here in midcoast maine and learning tons every day, just how I like it.
    Rob Brown
    Designer for Rockport Mechanical
    in beautiful Rockport Maine.
    RobGkcopp
  • Ironman
    Ironman Member Posts: 7,367
    Rich said:

    Rob, where have you been ? Have not seen you here or anywhere for quite awhile .

    Agreed.
    Rob, it's good to hear from you again.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • NRT_Rob
    NRT_Rob Member Posts: 1,013
    thanks guys, that means a lot. Happy Spring all around.
    Rob Brown
    Designer for Rockport Mechanical
    in beautiful Rockport Maine.
  • Gerg
    Gerg Member Posts: 15
    Hello, Okay, I'm just listening and learning. Thanks....To answer questions put to me....there is no buffer tank in the system, the 1.25" primary loop is about 6 foot long. Also I have left out of my diagram a hot water heater that is like a 4th zone. The hot water tank is next to the hydrobox and plumbed entirely with 1" copper. The hot water is working great. Also, I do see that A with the box around it on the control screen. Happy to hear more votes that the pipe sizes don't raise any questions. I still don't know exactly what steps I take to get heat loss numbers. What am I missing? Can you define the term "heat loss numbers" ? Thanks again.
  • NRT_Rob
    NRT_Rob Member Posts: 1,013
    To determine what water temperatures you need, how much baseboard, and whether the altherma would be enough for you, someone should have done a heat load calculation on each room of your house. That is used to size the baseboards for a particular water temperature, etc.

    I'm a little surprised you were seeing 128 out of the altherma in March. So that does make me wonder if your reset curve (the water temperature it provides vs the outdoor temperature, colder outside needs hotter water) is set properly.

    The buffer tank thing might be an issue in defrost. You don't sound like you have the minimum water content this unit requires. The domestic tank doesn't count.

    so those are the only two causes for concern I'm seeing as potential here. If your contractor can say "yeah, you need 120 degree water when it's 5 degrees outside" then he did the load calcs and set your reset curve properly. If he can't, then... I dunno.

    What water temp is is providing now, and how cold it is out?
    Rob Brown
    Designer for Rockport Mechanical
    in beautiful Rockport Maine.
  • Gerg
    Gerg Member Posts: 15
    The Set Temp display says 123 f and outside it is 43 f. The outside temp has warmed a lot in the last 2 months and in January we were in a bit of a crisis to get the house warm enough. At this time there is no practical problem since the outside temps are warmer, but that initial first winter is the reason I started asking questions about the installation.
    The contractor did do a set of calculations to determine baseboard lengths for each room and other considerations, which at the time I did not pay much attention to because I did not anticipate having concerns. As I think I said earlier, the contractor has been responsive and helpful, I am just trying to get up to speed so I can get optimum performance out of the system without being a pain in the neck.
  • Ironman
    Ironman Member Posts: 7,367
    Greg,
    Ask your contractor for a copy of the heat loss calculation. Then post it here (just the summary sheet). If he can't produce it, then there may be problems.

    You won't find anyone who knows the Altherma better than Rob.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    Rich_49
  • Rich_49
    Rich_49 Member Posts: 2,766
    Rob and Altherma . This is true .
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
  • Gerg
    Gerg Member Posts: 15
    Hi, Yes, I will talk to my contractor about getting a copy of his heat loss calculations and then I'll get back to you. It may take a day or two. Thanks...
  • NRT_Rob
    NRT_Rob Member Posts: 1,013
    That's a red flag. 123 at 43 is not sustainable for any colder outdoor temp.

    If you have the large series altherma (036-054) its absolute maximum temperature is 131 and its water temperature capability drops pretty steadily with outdoor temperature down to about 95-100 or so around 4-5 degree outdoor. IF your total heat load is lower than about 21,000 BTUs/hr (unlikely, but technically possible if the house is AWESOME) then maybe your electric element backups can carry you by themselves, but your reset curve is definitely set very high and you'll be on mostly straight electric when it gets much colder with those kinds of temps.

    If you have the smaller series (018-030) then the max temp is 122 and you are at max now. That one does hold its temperature capabilities longer at lower outdoor temps, but again this means your reset curve is still way too high and it's cause for concern in terms of what the final water temp expectation is.

    You definitely could benefit from a reset curve adjustment either way, you shouldn't have to run this hot when it's this mild out. But the key piece of info is what outdoor temp and water temp the baseboards are designed for.
    Rob Brown
    Designer for Rockport Mechanical
    in beautiful Rockport Maine.
    Rich_49