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Radiant tweaking?
josephny
Member Posts: 274
Following up on my previous post....
IBC SFC-199 (with IBC's primary/secondary premade manifold)
Uponor EP radiant manifold
4 circuits, ~275' each
1/2" HePex in JoistTraks
JoistTraks 8" OC, attached to the underside (from inside the basement) of ply subfloor with hardwood flooring on top of it and mineral wool under it (between the floor joists)
With system calling for heat and Grundfos UPS15-58FC running on high, the flow rate gauges show a 0.4gpm rate. That is with the manifold valves completely open.
With boiler radiant water temp set for 125* F, the temp at the manifold input is 110* and at the manifold return is 100*
Is my flow rate high enough? Or, too high?
Other than a buffer tank (which is on my to do list), is there anything I should change/adjust/tweak?
Thanks!
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Comments
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Do you actually have 125 at the boiler? A 15-degree difference is a little unusual, I wonder if there is a piping issue. Is it piped primary /secondary?
The .4 GPM and 10-degree delta sound pretty normal for those tubing lengths."If you can't explain it simply, you don't understand it well enough"
Albert Einstein0 -
Are you using the EP manifold stock thermometers to read the temps at the manifold ? If so , they are notoriously inaccurate , they'll show a Delta pretty well .You didn't get what you didn't pay for and it will never be what you thought it would .
Langans Plumbing & Heating LLC
732-751-1560
Serving most of New Jersey, Eastern Pa .
Consultation, Design & Installation anywhere
Rich McGrath 732-581-38330 -
It is pipes P/S, using the IBC EZ-Pipe.Zman said:Do you actually have 125 at the boiler? A 15-degree difference is a little unusual, I wonder if there is a piping issue. Is it piped primary /secondary?
The .4 GPM and 10-degree delta sound pretty normal for those tubing lengths.
I don't know if I actually have 125 coming out of the boiler.
I wonder if there is an accurate clamp-on thermometer for 1-1/4" copper that I can get to measure temps?
Using my extremely basic understanding, a 1.6gpm flow (0.4 * 4 circuits), with a 10 degree temp drop, results in 8000 BTU being radiated. I think I'd like a much higher radiation rate, no?
Thanks!0 -
Yes, I'm using the EP manifold stock thermometers. Maybe I should have plumbed in additional (and better quality) thermometers.Rich_49 said:Are you using the EP manifold stock thermometers to read the temps at the manifold ? If so , they are notoriously inaccurate , they'll show a Delta pretty well .
Nonetheless, you think the delta is reliable and that figure (10*) is something I question as a good delta.
Thanks!0 -
275' loops with a 15-58 on high and 110* water should be producing nearly double that flow rate across 4 loops. Is it water or is it glycol? Something doesn't add up here. How many feet of Joist Trak are being used for your 1100ft of tubing?0
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A 10* Delta T is widely accepted as the designed for Delta in a radiant floor . that being said , in newer more tightly built structures Deltas up to 20* work fineYou didn't get what you didn't pay for and it will never be what you thought it would .
Langans Plumbing & Heating LLC
732-751-1560
Serving most of New Jersey, Eastern Pa .
Consultation, Design & Installation anywhere
Rich McGrath 732-581-38331 -
Is 8,000 BTUs ~ 10 BTUs/Sqft? That sounds about right for 110 degree SWT."If you can't explain it simply, you don't understand it well enough"
Albert Einstein0 -
I'm using water.GroundUp said:275' loops with a 15-58 on high and 110* water should be producing nearly double that flow rate across 4 loops. Is it water or is it glycol? Something doesn't add up here. How many feet of Joist Trak are being used for your 1100ft of tubing?
I don't know how much joist trak is being used, but I'd say just about all of the tubing is in track. I would estimate about 800'
What could be going on?
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If you turn the temp up you will. 10 will probably work for most heating days."If you can't explain it simply, you don't understand it well enough"
Albert Einstein0 -
Update:
I raised the boiler radiant hot water set point to 135*
The thermometers built into the EP manifolds read 120 in/110 out.
I installed 2 Viega strap-on thermometers and they area 128/120. So, while temperature readings are different between the thermometers, the delta is closet.
I just today lowered the setpoint to 130.
Still not getting more than .5 or .6gpm in each of the 4 circuits -- tried pump on low/med/high.
Am I wrong that a larger delta would be better?
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