pri/sec piping & bypass?

Timco

Is there a specific rule of thumb for applying pri / sec piping? If this method is used, is a boiler bypass needed?

Thanks again,

Tim

Brad White_136

Tim

Could you be more specific as to type of boiler, (e.g.: cast iron, mod-con, copper tube, etc.) type of system (e.g.: converted gravity, fin-tube, radiant floors, etc.)

Just want to be sure what the application is and why you are asking.

As a general answer, primary-secondary in effect works as a bypass by maintaining the boiler temperature independently of the distribution temperature. How that is done differs of course.

Timco

Thanks a lot for the reply....I am replacing a snow man with a cast iron atmospheric boiler, 162,000 BTUH. The old system has two 2" loops. Figured I would move these seperate wit 15-58's rather than as one zone with a 2600 series. Now it has a big 'ol B&G and the water moves too fast. Takes forever to heat up. Heatloss is just shy of 160,000. Would pri / sec be better than a fixed flow control on a bypass? No reset for now....I quoted and they opted for later.

Thanks again,

Tim

Timco

Forgot to mention this system has many rads....CI. If dist temp does not need to be independant of the boiler temp, as with slab heat, then a typical bypass is the ticket?

t

Steamhead (in transit)

Tim, I prefer P-S

and the secondary circ should be sized to the EDR rather than the heat loss. How much EDR is there?

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Timco

I have that number somewhere....Will need to find it. I got the total EDR for each rad, but am not sure what rads are on what loop. Two loops. If I am using 15-58's, shouldn't I be able to dial them in?

Thanks again,

T

Steamhead (in transit)

Probably

but I bet you find you can run both loops with just one 15-58 or similar circ. There's only so much radiation you can serve with 2-inch pipe.

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Timco

I was figuring the cost of 2 15-58's was less than one 2664. House is fairly large...runs up 3 storis then out from there as best as I can tell. I tend to play safe & oversize...that's the beauty of the 3-speed selection.

T