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Putting system together - pump selection help

djohndjohn Posts: 93Member
Last time I built a complete hydronic system was 5 years ago so I would appreciate if you helped me refresh my knowledge a little bit and give an update of what is being used in 2013.



About 1,500sqf per floor: basement and 2 stories, well insulated (total heat loss about 52k BTU or 67k BTU using energy ). Big unknowns are how much additional heatloss happens through the drive under garage (part of the basement, 2 loops) and through stone foundation (some of it are interior basement walls).



To be safe, and compensate for coming global cooIing (ha!), I figured that Lochinvar Knight WHN155 is my thing (30BTU/sqf end up being 135k BTUs - around what this model is rated for) It will be field converted to LP. It's my first dip in the firetube design since I used mostly NTI before.



I plan on 1 zone per level. There are 6 loops already embedded in the basement slab and 1st and 2nd story will likely have 7-9 loops each. It's going to be joist trak install, with 1/2" durock and 1/2" travertine on top of 3/4" OSB subfloor. Obviously insulated, thinking about R-19.



There is more reading I have to on Lochinvar itself but I would plan of primary / secondary piping and zones operated by circulators, wired through Taco relay panel.



The main question I have would be the circulator selection. Lochinvar mentions "boiler pump" (with provided Grundfos UPS26-99FC) and "system pump". Always been a Taco guy but it looks like their ECM pump selection is non-existent for residential.



1. Should I use provided Grundfos pump for boiler/primary pump or pick something else? Variable speed viable here? What makes and models?

2. By "system pump" I reckon Lochinvar meant pump that would work with zone valves - and I would be using zone pumps. It looks like Taco 007 would be my choice here, what other options do I have? Makes sense to go variable speed? ECM?



I am pretty sure i don't need anything else like outdoor resets, etc. since all the work will be done by the boiler itself and then controls - 3 Ecobee thermostats.



Any help and advice is greatly appreciated.
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Comments

  • ZmanZman Posts: 2,331Member ✭✭✭
    Heat loss

    You should be able to do an accurate heat loss on your other floors. It would make your boiler sizing a bit more accurate. My guess is that the 155 is a bit big and the 110 a bit small. The point may be moot.

    You absolutely want to pipe primary/secondary per the manual.

    As for circulators, the boiler circ should not be a 26-99. A grundfos 15-58 or taco 007 is more than enough. More is not better with mod/cons.

    For the secondary, I have great luck with the grundfos alpha with zone valves and radiant.

    The Alpha is a delta p ecm circ that has a nice curve for most radiant systems.

    The curve on the 007 is a bit flat for radiant applications.

    If you are doing an indirect, It wants to be priority with it's own circ.

    Carl
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    ·
  • djohndjohn Posts: 93Member
    heatloss done

    Goddamnit, I just typed up entire reply and it didn't post for some reason. Have to start from scratch.



    I did pretty accurate heatloss calc and came with 52k BTU pure heatloss for the whole house, 85k BTU including propane caloric deration and 90k BTU including boiler efficiency (95%). So 95k BTU input + unknown heatloss through the foundation and drive under garage. Next unit down wouldn't work so WHN155 it is, I guess. 135k BTU input. And should be safe, with 5:1 turndown.



    Now, more about my design.

    All loops will be 1/2", full 300' rolls. Coming to 1" manifolds - 6 loops in basement, guessing 8 for 1st floor and 9 2nd floor. So about 23 loops total.



    At 125k BTU input from the boiler, it would be 3 equal zones at ~40k BTU each = 4GPM in each zone. 0.66GPM, 0.5GPM, 0.44GPM per loop in each zone. Using Nibco oxy barrier pex, with pressure drop at 0.016 per 1GPM. Please correct me, but I am calculating about between 2 and 3ft of head. Seems low.



    Being mod/con, I want to take advantage of it, so system will definitely run below 130F return temp. Not sure what exactly for slab and what for insulated joist trak. Have to dig out Siggy's book and do the calculations.



    And yes, you are correct on what comes with the boiler. My bad. It is 15-58. I have zero experience with Grundfos though. Being Taco 007 equivalent, does it mean my system would have all 007 pumps? 1 primary and 3 zone?



    Back to my questions:



    1. For the primary pump - is that Grundfos a good solution, or should I look into variable speed pumps? If so, which ones? Delta-T? Delta-P?



    2. For the zone pumps - I just discovered Bumblebee by Taco. Being similar rating to 007 and also being delta-T, is this my dream solution for zones? Or are there better ways? Good solution for primary pump?



    3. If I end up with variable speed zone pumps, do I still need a mixing valve for my slab zone? I am still not sure how different my design temps will be between slab and insulated joist trak.
    ·
  • hot rodhot rod Posts: 4,064Member ✭✭✭✭
    a small buffer

    with multiple connection points instead of P/S is another option. The tank replaces the close tees and offers dirt, air, separation, and a nice port to insert the boiler sensor.



    unless the required temperatures are more then 20° apart, one temperature is fine.



    the Delta P circs are a nice match, zone with valves.



    I like the Alpha, Xylem, Wilo, and now the Armstrong Compass are all good options.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
    ·
  • djohndjohn Posts: 93Member
    variable speed vs single speed

    Would a Bumblebee be better off as primary/boiler pump?

    Then regular 007's for zone pumps?



    Otherwise, not sure how the logic would work out between:

    - mod/con boiler (changing fire rate)

    - VS primary pump

    - 3x VS zone pumps.

    Endless adjusting loop?



    Also, could Bumblebee be used in single speed in zone pump application, just to take an advantage of the ECM efficiency? It's probably the least expensive ECM pump.
    ·
  • hot rodhot rod Posts: 4,064Member ✭✭✭✭
    My opinion

    is that any ECM circ will be more efficient at moving the load, if that is one of your goals.



    I'm not convinced a fixed delta t is desirable or advantageous on the boiler loop with a modulating, reset controlled boiler.



    If you want a modulating boiler with a modulating circ, I believe Viessmann is the only "off the shelf" option.



    The output for the VS boiler pump is on many of the boiler controls, but a US version of a circ to easily adapt to that signal is not quite on the shelves. An interface module is available for the Wilo, but the total cost gets a bit high.



    However it is a common circ in the Euro market and when them numbers work out, expect to see the 120V version. I have a few samples of these circs built to OEM specs. Solar specific, ECM, PWM models including drainback versions. If you have 230V available you can find these circ online from UK and other sites and build up your own V/S boiler circ.



    If one small 45W ECM circ can easily handle the entire distribution load, and dial itself in to the optimum flow rate, why would you want numerous zone circs?



    Delta P circs were designed to efficiently move the load and adapt to an ever-changing flow requirement. They are a perfect match for zone valves or TRVs , why re-invent the wheel, or impeller :)



    Personally I'd like to see a few tweaks to the BB before I consider it an equal to the other small ECM brands currently available. From my experience in fixed speed operation it is too noisey. In this day and age a circ should be run virtually noise frees. With only indicator lights or flow meters indicating flow. Decibel levels should not be in the same sentence with high efficient wet rotor ECM circ discussions.



    I'd like to see delta p option included in the menu. Lastly the motor should be able to be rotated so the display is always right side up and easily viewed, and programed, regardless of mounting position.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
    ·
  • ZmanZman Posts: 2,331Member ✭✭✭
    Like he said...

    Hot Rod is right on the money on the ecms.



    On your radiant side, check out these design manuals from uponer https://www.uponorpro.com/Technical-Support/Manuals.aspx



    If you design your panels to run at approximately the same temp, just run a single ecm  delta p circulator and zone valves with one temperature curve and voila,you have a simple, comfortable system. Keep it simple!



    If you take a circ like the alpha and set it to constant pressure mode, you will always have the  correct flow of water using the least amount electricity.



    Taco is a fine company. They just don't have the best product for your application.



    Carl
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    ·
  • djohndjohn Posts: 93Member
    delta p vs delta t

    From what I understand WHN155 can control variable speed boiler/primary pump.

    And yes, efficiency is one of my goals, even if ECM pump is not being used in variable speed mode.



    In circulator operated zones (so 1 primary + 3 zone pumps),  are you saying that:

    - Aplha (delta p) is better suited for boiler/primary pump than Bumblebee (delta t)?

    - Aplha (delta p) is better suited for zone pump than Bumblebee (delta t)?



    I thought that Alpha is meant for zone valve and TRV systems as the system pump only (not boiler pump)
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  • SWEISWEI Posts: 5,048Member ✭✭✭✭
    Primary pump

    look for a Taco VVF pump, which can accept the 0-10V control signal from the WHN.



    Speaking of which, I missed the part where a 155k boiler was a good idea for a heat loss of "52k BTU or 67k."  If it were my house, I'd probably take another look at the heat loss and see if I could make a WHN-055 work.  Certainly no larger than a WHN-085 for that.
    ·
  • djohndjohn Posts: 93Member
    heatloss

    Heatloss called for 90K input based on propane caloric deration and boiler efficiendcy. WHN155 is 125K input and modulates 5:1.



    That 90K heatloss doesn't include unknowns as drive under garage and stone wall partitioned foundation (couldn't insulate under) and some exposed perimeter stone foundation (has just R-5 outside and nothing under).



    So one would say that the boiler with it's input modulating between 25k and 125k BTU would fit a 90k BTU (+ some) load on 3 level house





    Could only found some brief reference to 0012F-WF pump, not on Taco website and doesn't look like right one for my application.
    ·
  • djohndjohn Posts: 93Member
    edited December 2013
    which boiler pump

    Just to be clear, I am not disputing that Alpha is the right solution for single system pump when zones are activated by zone valves.



    I have never built a system with zone valves. Never liked them and feel that zone pumps are more dependable. It's still an option though, maybe worth discussing.



    So maybe let's do it step by step - boiler pump selection shouldn't be influenced by whether there will be 3 zone pumps or 1 system pump, right?



    Which pump should I use for boiler pump? It looks like I need about 12GPM at 3-4ft of head max. Would like to go ECM way, whether it runs as variable speed or not - and I see why boiler pump could show it's full potential as VS, in both zone valve and zone pump systems.



    Edit:

    WHN155 shows 15GPM at 4.26ft of head.

    Taco 007 is listed as recommended boiler circulator.
    ·
  • Jean-David BeyerJean-David Beyer Posts: 2,472Member ✭✭✭
    My former heating contractor said that too. He is FORMER for reasons.

    Oversizing a mod-con is usually a very bad idea. I calculated out the heat loss of my house, when it was 0F outside at about 30,000 BTU/hour. And design temperature around here is 14F. My former heating contractor suggested a 105,000 BTU/hour boiler to be "on the safe side." He said it would modulate down to 21,000 BTU/hour so it would be OK.



    That is nuts. I got the smallest boiler in the product line (80,000 BTU/hr input) that goes down to 16,000 BTU/hour. And that is no where near low enough. Since most mod-cons have turn down ratio of 5:1 or so, you will never get them to go down far enough at all times. And if it does not go down far enough, it will cycle, perhaps rapidly. And you do not want that. One zone needs 6250 BTU/hour when it is 0F outside. So if it is 50F outside, it needs even less. I wish mine would turn down to 1000 BTU/hour, but it doesn't.
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  • djohndjohn Posts: 93Member
    i agree, but

    I agree that grossly oversized boilers are not good, but again, my H/L is 90kBTU (plus some, could be 10-15kBTU) and WHN155 inputs 125kBTU. Next smaller model is 89kBTU input, which will not be enough, especially at below-design temps.



    What really happens is I am trading off a min modulating input of 18kBTU (110 model) for 25kBTU (155 model) to make sure my 4 letters don't freeze in Wisconsin winter.



    If it was a complete new construction, no drive under garage, no stone foundation partitions or walls, and I could fully control all aspects of this building, to guarantee a 90kBTU heatloss max, I would probably go for 89kBTU boiler.



    Just too many unknowns to justify smaller boiler.
    ·
  • djohndjohn Posts: 93Member
    what mode?

    "I'm not convinced a fixed delta t is desirable or advantageous on the boiler loop with a modulating, reset controlled boiler"



    What mode should ECM/VS circ used at then?

    And what would be a good make/model choice?



    WHN155 shows 4.26 ft of head at 15GPM and lists Taco 007 as recommended circ.
    ·
  • SWEISWEI Posts: 5,048Member ✭✭✭✭
    edited December 2013
    mod/con boiler sizing

    Look at the DOE output ratings for each model.  WHL-085 puts out 79,000 BTU/hr.  There is no derating for LPG.  At one point your heat loss was 52k?



    Remember that heat loss calculations already include a fudge factor (quite a bit larger than most would imagine based on my experience.)
    ·
  • djohndjohn Posts: 93Member
    my xls worksheet sucks?

    Thanks for being persistant on this - I think there is something wrong with my heatloss calc xls file.



    My xls heatloss worksheet shows 52k BTU heat loss.



    Then, it shows 80% caloric deration for NG resulting in 64kBTU

    And 95% boiler efficiency resulting in ~68k BTU



    Also shows 60% caloric deration for LP resulting in 86kBTU (so you are saying it shouldn't be there?)

    And 95% boiler efficiency resulting in ~90kBTU





    As far as uninsulated stone walls and stone partitions - I played with the numbers.

    As is, entire 1,634 sqf of basement at R-10 (2" F250 under slab) results in heatloss of 4,085 BTU.



    Now, I calculated the area with stone partition walls and stone exterior foundation walls and it adds up to about 200 sqf (footprint area). So, if I use 200sqf at R-1 and

    1,434 at R-10, the basement floor heatloss changes to over 17kBTU (from 4)



    So here is one part of my unknown heatloss.

    As is then, the total heatloss is ~66k BTU and the only unknown left is how much heat I lose through operation of garage doors in drive under garage.



    Any idea how I could figure that out? Garage is 25x21ft, has R-10 floor, will be separated from the house by ~R-20 ceiling, 30ft of R-1 stone wall and 16 ft of ~R20 wall.



    I don't expect the operation of garage doors to have major cooling effect on interior walls, but that space will have to be reheated (no thermostat in garage though) several times a day.
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  • hot rodhot rod Posts: 4,064Member ✭✭✭✭
    web search

    the pumps you are considering and see the pump curve. I "googled" Grundfos Alpha pump curve and this shows up.



    Ideally the circ covers your load in the mid 1/3 of the curve. Don't select a circ that runs at the very top, or bottom of the curve, very in-efficient and un-healthy for the device.



    Looks like speed 3 is the perfect setting if this is your circ choice.



    Usually the boiler I&O manual shows pump requirement with a few different delta T choices.



    The Grundfos and Wilo have the longest track record with small ECMs in our market.



    The Xylem looks like a Laing design, good track record with that brand, probably fewer in the field here in the US. I like the two choices they offer, and the way the selector switch varies the speeds. The large brass nut for motor removal is quick and simple.



    Just got an Armstrong Compass ECM, not installed yet but some nice installer friendly features.



    At this point select the model that fits your application, deal with a company that you like and that stands behind the product.



    They all circulate fluid just fine, failures are often caused by operator error, or harsh fluid conditions.
    png
    png
    Screen shot 2013-12-03 at 11.48.05 AM.png
    0B
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
    ·
  • djohndjohn Posts: 93Member
    edited December 2013
    good chart

    It looks like because of errors - my own and in xls heatcalc, the real heatloss number is around 66k BTU plus 25x21 drive under garage (doors opening 4-6 times a day) so probably the correct choice would be WHN110 (89k BTU input, so about 20BTU/sqf).



    It specifies boiler pump at 10GPM  and 1.53 ft of head.

    http://s3.pexsupply.com/product_files/WHN-110-Install.pdf

    Like other Knights, it lists 0-10V signal to control variable speed boiler pump.



    So to sum up, my options until now would be:

    - Taco Bumblebee

    http://s3.pexsupply.com/product_files/Taco%20-%20HEC-2%20-%20Install%20Instructions.pdf

    - Grundfos Alpha

    http://s3.pexsupply.com/manuals/1281025495227/35863_PROD_FILE.pdf

    - Wilo Eco

    http://s3.pexsupply.com/product_files/4145539-Submittal.pdf

    (can't find armstrong compass, xylem and laing right now)



    Looking at pump curves, Wilo seems like it barely fits the need and Alpha autoadapt feature starts above 4ft of head - would it mean I am down to Bumblebee for my boiler pump?
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  • SWEISWEI Posts: 5,048Member ✭✭✭✭
    Too many adjustments

    Get rid of these:



    80% caloric deration for NG resulting in 64kBTU And 95% boiler efficiency resulting in ~68k BTU







    60% caloric deration for LP resulting in 86kBTU (so you are saying it shouldn't be there?) And 95% boiler efficiency resulting in ~90kBTU



    And use the DOE Output numbers from the manufacturer together with the calculated heat loss.



    What interior temp are you using for the basement?  Does it reflect the intended occupancy (or lack thereof) for the basement?  Is your ground temp correct?
    ·
  • SWEISWEI Posts: 5,048Member ✭✭✭✭
    I would use

    a WHL-085 with a Taco 006-VVF4 pump.
    ·
  • djohndjohn Posts: 93Member
    basement

    I am looking for constant temp throughout the house, 70F.

    Basement consists of some living space, storage space, mechanical room, garage. Garage obviously will be losing more heat when doors open, then warming up. There is also a large glass patio door on the walkout side.



    This basement is an unknown area physically, really, since some of it is rubble stone foundation, some poured concrete, some concrete block. Some insulated, some not.



    That's why 66kBTU heat loss I am coming with now is likely bigger.
    ·
  • SWEISWEI Posts: 5,048Member ✭✭✭✭
    edited December 2013
    Zone valves

    try the Taco Zone Sentry.  They use a ball valve design and only need 2VA.



    If you have to use zone pumps, try the ecocirc e-series.
    ·
  • djohndjohn Posts: 93Member
    85

    You would really go 2 sizes down?



    I think a 66kBTU heatloss is a rather low estimate right now. WHN110 gives me 89k BTU input and turndown all the way to 22kBTU. Which would be exactly 1/3rd load or 1 zone calling for heat.



    WHN085 puts me at 69kBTU input, which is borderline to my possibly faulty and imperfect heatloss calc. Nice thing is another 5kBTU turndown - down to 17kBTU.



    I already have 3" venting in place, as I was getting ready for 155 model. 085 calls for 2" venting and makes me even more uneasy about the choice. I have just digested a needed change to 1 model down :)



    As far as boiler pump goes, Lochinvar lists 007 for all applications from 055 to 155 model.



    Why 006, a non-ECM model? Motivated by 0-10V input? It looks like no ECM pump has it, but it can be dealt with by another controller unit or just set to work independently of the boiler - is that the worry? (logics between ECM VS pump and mod/con?)
    ·
  • djohndjohn Posts: 93Member
    zone valves

    Do I sense a push towards this setup:

    - WHL-085

    - Taco 006-VVF4 boiler pump

    - Grundfos Alpha system pump

    - 3x zone sentryvalves



    I like the last 2 points, even though it would be my first time with zone valves.

    Would feel better with 110 boiler. And would love ECM boiler pump.
    ·
  • djohndjohn Posts: 93Member
    head loss

    Since I am not home right now and we are talking about another boiler, can you help me figure out my head?



    WHN110 boiler, calling for 10GPM at 1.53ft of head. Not sure about boiler pump yet.



    300ft loops of 1/2" pex. 6 port, 8 port, 9 port manifolds. (guessing last 2)

    Still debating 3 zone pumps vs single Alpha with zone valves.
    ·
  • SWEISWEI Posts: 5,048Member ✭✭✭✭
    Boiler pump

    Given that the WHL has a 0-10V output for the boiler pump, I'd recommend the VVF even though it's not an ECM.  I hope we see some options over here soon -- direct control of the pump speed by the boiler's internal controls is by far the best arrangement.



    I try to minimize or even eliminate zoning wherever practical.  Crank your thermostats all the way up (really, like 90ºF) and then spend some time dialing in your reset curve and balancing flow throughout the system.  After that's done (which could take several weeks; be patient) set the stats 2-3ºF above the desired room temp and they will act as high limit controls.
    ·
  • SWEISWEI Posts: 5,048Member ✭✭✭✭
    Head loss

    on the firetube HX is essentially zero.  Looking at the 35ºF chart, I see 0.37 ft of head at 5 GPM.  I sincerely doubt the entire circuit will exceed 1 ft.  Turndown on those VVF pumps is 300:1 according to Taco, but the 006 is the smallest cast iron model you can buy.  They do offer a 003 VVF in bronze or stainless, but no unions as far as I know, so replacing them in the field gets tough. 
    ·
  • djohndjohn Posts: 93Member
    0-10V

    I thought there is a way to wire a 0-10V output from the boiler with the ECM pump, using another component. I could swear I read something about it either in some pump or boiler literature.



    If that gets pricey, what about depending on ECM pump's logic?
    ·
  • djohndjohn Posts: 93Member
    edited December 2013
    head

    Lochinvar literature mentions 1.53ft of head on boiler loop (at 10GPM) That looks to be well below Wilo's curve and outside of Alpha's autoadapt area.



    I was wondering about actual head past:

    - the zone pump

    - or past the system pump (should be close I think)
    ·
  • SWEISWEI Posts: 5,048Member ✭✭✭✭
    edited December 2013
    0-10V control inputs

    Are available on the larger (Magna, Stratos, Viridian) models but not on the "residential" models.  Again, I REALLY wish we had an option for this, along with some smaller ECM circs (all of which have curves roughly equivalent to that of a 008.)



    The internal controls of a ∆P pump will not play nice with a modulating boiler.  The internal controls on a ∆T pump should work, but we've seen enough problems reported here that I hesitate to recommend them (plus, the 008 curve matches quite poorly with a low resistance HX.)
    ·
  • djohndjohn Posts: 93Member
    cost

    And I can only concur, especially after looking at 00-VV series pricing. Holy smokes!



    Do you really think it's a better solution than running a Bumblebee as a boiler pump?

    ...at over 2x the cost
    ·
  • SWEISWEI Posts: 5,048Member ✭✭✭✭
    Pick your ∆P favorite

    and drop the primary-secondary, pump it straight through the HX.  One pump for the whole system.
    ·
  • djohndjohn Posts: 93Member
    no P/S

    No P/S? You sir, just started a revolution in my brain.

    First no zone pumps, now no P/S piping? :)



    Since there is only 1 Alpha (delta p) - it has to work, right?

    It is supposed to handle different loads of zone combinations better than delta t thermostat, right? (like Bumblebee)



    Should I still do a detailed head loss calc?



    WHN110 and other Lochinvars still advice P/S piping. Am I safe without it?

    Never done it like that, so asking :)
    ·
  • djohndjohn Posts: 93Member
    flanges

    Can't find 6 and 7 model of 00-VV with 1" flange options. Crazy expensive too :(
    ·
  • djohndjohn Posts: 93Member
    new thread

    I think I should start a new thread since you just gave a whole new spin to my problem :)



    Assuming my design will look similar to this page off Lochinvar manual (except for DHW zone):

    http://s3.pexsupply.com/product_files/WHN-110-Install.pdf



    New pending questions will be:

    - no low loss header or hydraulic separator needed?

    - differential pressure bypass valve recommended?

    - Y strainer? (never used it with NTI)

    - how much of temp difference can zone valves handle? (slab vs R-19'd joist trak)

    - what model of zone valves?
    pdf
    pdf
    fullflow.pdf
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    ·
  • SWEISWEI Posts: 5,048Member ✭✭✭✭
    Direct pumping

    If you read carefully, you will see that direct pumping is approved.



    No need for a bypass valve if you use a ∆P circ.



    Taco claims a Bumble Bee will work even better.  I can see circumstances where it might produce lower return temps, but but I haven't tried one.



    Still need to do a head loss, but the majority of residential jobs will work with that curve.
    ·
  • djohndjohn Posts: 93Member
    edited December 2013
    head

    Yes, I found direct piping diagram. P/S piping is still the golden standard for pretty much all manufacturers, correct?



    I was just thinking about point of exact head loss, since there is only one Bumblebee and one Alpha model. Unless you mean to be able to choose between them to better fit the curve.



    Since we changed the subject so much, I started a new thread.
    ·
  • SWEISWEI Posts: 5,048Member ✭✭✭✭
    Primary/secondary piping

    it pretty much mandatory with the high head loss of most mod/cons.  It allows you to run a different ∆T on the boiler and the emitters (particularly helpful with radiant floors.)



    It also reduces the chance of a clueless installer killing the boiler.  Combine that with lawyers and you see where significant portions of installation manuals originate.
    ·
  • djohndjohn Posts: 93Member
    single

    True, but then WHN110 has only 1.53ft of head loss at 10GPM and entire system head loss is probably around 4-5ft.



    For pure simplistic approach, I love the idea of single pump.
    ·
  • djohndjohn Posts: 93Member
    edited December 2013
    head

    As I won't be home for couple more days and have access to Siggy's book, could you verify my numbers on the head loss?



    1.53ft of boiler and I am getting another 3.1ft of the remaining system. Not sure if that's right.



    Edit:

    Using Uponor's table, I am coming with:

    - 3.4ft of head in zone 1 (slab, 6 loops)

    - 2.3ft of head in zone 2 (joist trak, 7 loops)

    - 2ft of head in zone 3 (joist rak, 8 loops)



    If that is correct, then 3.4ft of distribution head plus 1.5ft of boiler head = ~5ft of head for entire system.



    Looking at Alpha and Bumblebee - 10GPM at 5ft of head and:

    - Alpha is barely in autoadapt zone. Close to 2nd speed curve

    - Bumblebee is almost at the highest speed



    Any additional insights on pump selection because of system head?
    ·
  • SWEISWEI Posts: 5,048Member ✭✭✭✭
    Fire-tube heat exchangers are different

    Their low head loss allows greater flexibility in system design, even to the point of moderate knuckleheading.  They also save on pumping costs, tolerate hard water somewhat better, and seem to need less frequent maintenance.



    Pioneered by Triangle Tube about a decade ago, they are now available from many boiler manufacturers (including Lochinvar.)
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