Radiant temp drop?

GW

after my question on how much a pump draws and the cost to run it, I may want to downsize my 26-99 pump on my 10MM tubing. 2.45 Amps... that's a bit much!

I'm too lazy to out to my truck and strap on my K-couple, I figured I'll do that once someone clues me in on some ideas on deltaT. The gauges on the S & R manifold are only a few degrees off (C, not F), but I'd put more faith in my Fluke 16 with clamp on.

BTW, I have about 11 runs with a max of about 250/270' or so; I can't really remember it was 7 years ago I think. I'm assuming the dT is the real deal.

Shall I slip in a 26-64? How about a couple of 15-42's in series to boost the head loss?

Thanks, you guys rock.

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Brad White

Back to Square One

I too had a 26-99 on a radiant BIM manifold for several years. 1/6 HP for one small bathroom (spare ports not hooked up yet) and my electric bill suffered. I replaced it with a spare 15-42 (same 6-1/2" flange-to-flange dimension). My electric bill dropped enough to notice.

However, this is one zone, 3/8" (10MM) in Climate Panel and 165 feet round trip. About 8-10 degrees delta-T, limited by my ability to measure and the time of day. Naturally where this fell on the pump curve was way up to the left.

For your condition, I would go back to basics, total flow of all circuits versus pressure drop of the worst circuit and select accordingly.

I suspect that you will need about 3 feet of head if running 0.25 GPM in 10 MM tube. Add to that your local losses for the manifold and mixing valve, maybe another foot or so. Call it 4.5 feet of head. If you have 11 runs at 0.25 GPM (I have no idea but all things being equal) that is a total of 3.0 GPM rounded up. Seems workable with a smaller circulator. One way to find out...

hr

11 loops trying to move how many btu's ?

that would be the way to size the circ correctly

Got a RadPad? That too would help you do the number crunching.

You need to do the calcs on your own and come back for a "homework" check

hot rod

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heatboy

Install the 15 - 58.........

........and then check your system. If you get a 20° to 25° delta t (which I suspect) and the room is warm.............?

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GW

OK

I must be looking like an idiot by now; but if the Viessamnn room sensor picks up the lower flow, thereby reducing heat transfer, I'm guessing the room sensor will yell down to the boiler and kick up the temperature. I've got the F module on the Trimatic MC with room sensing capability.

Thanks HR... shheeesh!

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