correct injection size

Kal Row

if my IBR load is 110kbtu and my boiler and system loops are 1-1/4" based on that load, what size pipe do i use for the variable speed closely spaced tee's injection - is there a known formula? - thanks

Kal Row

injection pipe size

if my IBR load is 110kbtu and my boiler and system loops are 1-1/4" based on that load, what size pipe do i use for the variable speed closely spaced tee's injection - is there a known formula? - thanks

Jed_2

Injection Bridge Size

Yes. Your VSIM Control I/O will take you through the steps; ...
or, you can get Siggy's Radiant Precision and it's all spelled out.
Good Luck

Jed

Paul Rohrs

Injection Pump Sizing

It depends.....

What is your primary loop temp, what delta T are you using, and what secondary loop temps?

Here is a template that you can plug in different values with. Change the Delta T and see what happens. Change the boiler Primary loop temp 10° and see what happens. Simple math, but necessary. I concur with Jed about Mr.Siegenthalers book. And who can forget about Mr.Holohans books. Pumping Away and Primary-secondary piping are a MUST. Christmas is just around the corner, treat yourself or start dropping major hints.

email me if you have further questions.

Regards,

PR

Kal Row

injection pipe size

i clicked on your attacment and got nothing.

i have holohan's books, and just ordered sigentalers book/cd
i have the gama 2000 book from the course, and i have attached a pdf of the system.

all the pre-packaged systems out there use
smaller pipe for the injection so i am a little confused,
i understand that there would be almost no piping/fitting headloss in that part, but at the end of the day wouldn't it have to be able to carry the full btu load in this case 117kbtu which according to the gama chart requires 1-1/4"?

- this is what i get for getting fancy - the origonal system had no zone valves and one pump on the return, part of the house was aways cold, and there was always air problems - i am trying to resolve all that

Paul Rohrs

Attachment

Yeah, that was weird. Open Microsoft Word and it should open fine.

PR

Kal Row

where is it

Paul Rohrs

Here it is....

Injection Pump Formula

Fv = (F1 x Ts)divided by (T1 x Tr)



Fv = Injection Flow Rate - ?

T1 = Boiler Supply Temp - 180°

Ts = System Delta T - 20°

F1 = System Flow - 20 GPM

Tr = System Return - 105°



Fv = (20 x 20) divided by (180 - 105)



Fv = 400 divided by 75



Fv = 5.33 GPM

Again, check your system design and plug in the correct variables.

PR

Kal Row

thanks

Wayco Wayne

Hey guys

I am watching this thread with some interest since I want to size my injection loops correctly. I was given an equation thst goes like so. Btuh for secondary zone divided by (490 x delta tee) = GPM for secondary zone. The delta tee is the wild card. If your secondary zone is a radiant floor buried in concrete you may need only 100 degrees, so your delta tee could be 180 boiler water minus 100 for a delta of 80. For example; Say you have a system that requires 15000 btu's. Divide that by 490 x 80 and you get a gpm of .38. Since 1/2 inch copper pipe can handle 1.5 gpm you could probably go smaller. I often run injection loop runs across basements with 1/2 inch pex. I could probably go smaller.

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Kal Row

dilemma

i am re-doing a hydronic baseboard system and adding indirect domestic hot water i am using the teckmar 371 whole house control to run the whole show with setback
i am re-doing a hydronic baseboard system and adding indirect domestic hot water i am using the teckmar 371 whole house control to run the whole show with setback
and vari-speed injection, this way i have boiler protection, system protection and all sorts of ontrol and efficiency goodies, my confusion is, that since my load is
designed for 180 in 160 out, when i am running at full load with all the zone valves open, shouldn't the injection system be flowing the full load of 11.7gpm for 117kbtu load and as such wouldn't it need 1-1/4" pipe like the gama chart specs?
all the formula's are nice - i want some logic and understanding!!!
see my attached diagram (borris.pdf) in msg 4 of this thread

according to the formula the nice Paul Rohrs sent me it IS the same
Delta-t 20 * priflow 11.7 / supply 180 - return 160 = injection at 11.7

why do i see all the prepackaged pri/sec units out there have smaller injection piping???
are they all designed to only go from hotter boilers to always lower temperature secondaries???

what i am getting from my setup, is boiler protection, and load control, based on outdoor reset on warmer days, when the secondary would be cooler than the primary - however when i am at max, the injection is going to have to run full speed 11.7, and would have to be piped as such,
- InMyHumbleOpinion

ps - the tkemar 371 is costing me $800, you'd think that would have an email address where i can send questions to, not so, they only have reps, i dont like second hand tech support

hr

The tekmar site

as well as the instructions have good essay and installation info. www.tekmarcontrols.com.

Basically you are using a wide delta tee to move the load through small pipes. If you boiler runs 160-180 and the radiant needs 100, then you are running an average 70 degree delta t. This is where the small pipe size is able to carry a lot of btus.

It took a while for me to grasp the idea of a 1/2" pipe moving 100,000 load. It does!

Siggys design software allows you to pick various delta t options and shows the pipe size needed. It is a concept that works in other hydronic applications also. home run panel radiators, near boiler piping, mini tube, all can play the wide delta T game.

hot rod

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Kal Row

70 delta-t

only works with radiant, with baseboard, the first part will heat and the rest of the house would freeze

goes to show you the dead men were right - a good steam
system is still the bes, it will heat the whole show
in no time

hr

You are right

70 would be wide for a baseboard system.

Steam is a wonderful medium for moving energy. Lot of heat carring ability. Excellent on district systems and industrial uses.

In residential applications, I wonder, however why go to a change of phase requiring 210 degree temperatures, when many radiant systems heat with temperatures in the 120 F range. Certainly it is most efficient to heat the space with the lowest possible temperature.

Hense the 371 control you have!

hot rod

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eleft(retired)_3

save $$$???

Check this PDF simple..ready to go.

hydronicsmike

A good friend of mine...

...made up this spread sheet.
Hope this helps.

Mike

Kal Row

re save $$$

yeh, i saw it in vegas at ISH, it donesn't begin to
do everything i could do with the tekmar 371 - and, based on it's built in sizing, i would have to run my boiler at 200 in order to make the boiler to system injection ratios fly, for a baseboard load at 180,
all these packaged things were designed for radiant
- besides if i am anyway using a 371 control
it's less expensive to pipe it myself
- i spoke to the tkemar rep - i have it right, the full load injection ratio is 100%,
the tekmar 371 will only slow down the pump to let the boiler loop heat up or when it's warmer outside and the baseboards dont have to be at 180

what i still dont have is correct piping sizes - if all
three pumps are running full - might not the head
pressures add up somehow

John Siegenthaler

injection pipe sizing

As Hot Rod mentioned, the latest version of the Hydroncis Design Studio software (V1.10) contains a new module called the injection mixing simulator. It allows you to specify all the typical operating conditions such as primary loop temperature, distribution loop supply temperature, and them simulate the performance of the injection system for a specified piping type, size, and length, along with a specific user-selected injection pump. The module also determines the setting of the injection balancing valve such that the injection pump is running at full speed under design load conditions.

This module allows you to evaluate VS injection mixing for both low temperature (radiant) and higher temperature (baseboard / panel rad) distribution systems.

The attached image shows a snap shot of the screen. You can read more about the module at www.hydronicpros.com under software products. You can also order the latest version of the software through Dan's bookstore.

Siggy

Mark J Strawcutter

isolated

with the "closely spaced Ts" you have hydronic isolation between the loops. So, no, the pumps won't interfere with each other.

Mark

Kal Row

injection pipe sizing

i just ordered the ltest version of your book that supposed to come with a basic version of the sofware - does it include that?

also the tekmar essays 021 and 022 talk about a thermal
trap using at least a 1ft drop, yet someware else i read
that the trap needs to go up and down at least 1ft, what is the real answer?

hydronicsmike

Gotta have a minimum...

...drop of 1ft. If you can make it more, that would be better.

Best yet, eliminate all the TA-Ra and simply run your boiler loop along the ceiling and drop down with your injection loop. Ceiling is normally about 8ft(or 9ft). After you dropped down with your injection loop, your system loop could be at about 5 or 6ft height. This would give you a 3ft drop, which is certainly enough.

Hope this makes sense.

Mike

eleft(retired)_3

based on it's built in sizing?

I would suggest you witness the operation of variable speed injection before you spend big bucks on all the bells and whistles.
Manifolds for 1/2" pex, zone controller with priority, two zone valves, one circulator pump and the W/M IPP will do.

al