Onix Tubing Installation Manual

Watts Radiant: Onix Installation Manual page 67
PRESSURE DROP (Feet of Head Pressure Drop per Lineal Foot of Tubing)
Q
s
HEAT REQUIRED (BTU/h) FOR AREA SERVED BY ONE CIRCUIT
Watts Radiant PRESSURE DROP CHART FOR Onix
50% Ethylene Glycol/50% Water
TM
TM
FLOW RATE (GPM) AT 20 F T
0.0001
0.001 0.01 0.10.03 1.0
3/8" Tubing
1/2" Tubing
5/8" Tubing
3/4" Tubing
40,000
30,000
20,000
10,000
9,000
8,000
7,000
6,000
5,000
4,000
3,000
2,000
1,000
900
800
700
600
500
5
4
3
2
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.09
0.08
0.07
0.06
1 ft/sec
2 ft/sec
3 ft/sec
7 ft/sec
1.5 ft/sec
5 ft/sec
4 ft/sec
6 ft/sec
0.05
50,000
1" Tubing
Notes: 1. The heat required is the energy the boiler must deliver for the calculated heat output of a circuit. If only the net heat output of
the circuit is known, multiply by 1.1 to get Q
s
, assuming the back and edges are insulated or space below is heated.
2. If the ∆T is different from 20°F, the value of Q
s
must be multiplied by 20/∆T.
3. Numbers from 1-7 in graph show the average water velocity in the hose (ft./sec).
4. This chart is for 50% ethylene glycol/50% water mixture only.
5. Remember to correct the flow rate for the different heat carrying capacity of ethylene glycol, as opposed to plain water.
Typical pressure drop chart for ethylene glycol systems.
Appendix