primary/secondary piping diagrams with dual boilers

siggy

Here's another option if you need lots of DHW and can't find an indirect with enough heat exchanger capacity. The key is not creating any bottlenecks to heat transfer of flow betweent he boiler array and the tank.

Siggy

jim f_3

primary/secondary piping diagrams with dual boilers

does anyone have any good piping diagrams for a primary/secondarypiping arrangement using 2 gas boilers and large 120 gallon indirect hot water heater.
thanks in advance!!
jim f
tri-city heating and cooling
milford, ct

ron v

pri/sec pics

hope these help.

Rely_2

P/S piping dual boilers

same as p/s piping single boiler app. one question what will control the boilers? Taco pc702 will do a good job because the load will not always need both to fire.

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jeff_51

go to thread called piping buffer tank

there is a sketch showing a primary loop with a boiler and a buffer tank. Just pretend the buffer tank is a boiler and both are pumping into the primary loop

hr

A few way to do this

how many loads? What temperture? I'd pipe condensors different from convential. Here are some ideas.

http://www.pmengineer.com/CDA/ArticleInformation/coverstory/BNPCoverStoryItem/0,2730,83529,00.html

hot rod

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jim f_3

thanks for the reply,

i have 2 126,000 gas fired direct vent boilers to provide 4 hydronic air handlers approx 40-80k btus each, 40k btu for hydronic space heater in garage and a 120 gallon indirect hot water heater. manifolds will also have 2 future zones if needed.

i am starting to design my headers so i can have them fabricated by earthlee. my big thing is i want to make sure my indirect is taken at the right place.

so far my design will employ 2" main with first tee being 2" for the indirect and 14 1" secondary supplies

jim f
tri-city

hr

Some more info

http://www.pmengineer.com/CDA/ArticleInformation/coverstory/BNPCoverStoryItem/0,2730,17213,00.html

I'll attach a pic of figure 5 since it didn't make the online version. Notice how the indirect plumbs in this drawing. Also the high temperature loads up on top right.

Keep in mind every take off will see a lower temperature with a row of closely spaced tees on a header. This may or may not be an issue for the last set of tees?

You could pull the indirects of a parallel loop also, instead of the primary loop. This is shown in #5

Now, if you need all the secondary loads to see the same temperature, a parallel primary loop would be better. A lot more pump and piping needed. Crude drawing

hot rod

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siggy

high capacity DHW

Here's another option if you can't find an indirect with enough heat exchange capacity. the key is not creating bottlenecks to flow or heat transfer betweent he boiler array and the tank.

Siggy