Specification

16
Table 16.1 and the formulas below are used to determine the heating capacity (Btu/hr) of a unit heater at a water temperature and/
or entering air temperature other than standard conditions of 200° entering water temperature, 60° entering air temperature.
Table 16.1
Hot Water Heating Capacity Conversion Factors
Entering Water Entering Air Temperature (°F)
Temp. (°F) 0 10 20 30 40 50 60 70 80 90 100
60 0.462 0.380 0.300 0.222 0.146 0.072 0 0 0 0 0
70 0.539 0.456 0.375 0.296 0.219 0.145 0.071 0 0 0 0
80 0.615 0.531 0.450 0.370 0.293 0.217 0.143 0.071 0 0 0
90 0.692 0.607 0.524 0.444 0.366 0.289 0.214 0.141 0.070 0 0
100 0.769 0.683 0.599 0.518 0.439 0.361 0.286 0.212 0.140 0.069 0
110 0.846 0.759 0.674 0.592 0.512 0.434 0.357 0.283 0.210 0.138 0.068
120 0.923 0.835 0.749 0.666 0.585 0.506 0.429 0.353 0.279 0.207 0.137
130 1.000 0.911 0.824 0.740 0.658 0.578 0.500 0.424 0.349 0.276 0.205
140 1.077 0.987 0.899 0.814 0.731 0.651 0.571 0.494 0.419 0.345 0.273
150 1.154 1.063 0.974 0.888 0.805 0.723 0.643 0.565 0.489 0.414 0.342
160 1.231 1.139 1.049 0.962 0.878 0.795 0.714 0.636 0.559 0.483 0.410
170 1.308 1.215 1.124 1.036 0.950 0.867 0.786 0.706 0.629 0.552 0.478
180 1.385 1.291 1.199 1.110 1.024 0.940 0.857 0.777 0.699 0.621 0.547
190 1.462 1.367 1.274 1.184 1.097 1.012 0.929 0.848 0.768 0.690 0.615
200 1.539 1.443 1.349 1.258 1.170 1.084 1.000 0.918 0.838 0.759 0.684
210 1.615 1.519 1.424 1.332 1.243 1.157 1.071 0.989 0.908 0.828 0.752
220 1.692 1.594 1.499 1.406 1.312 1.229 1.143 1.060 0.978 0.897 0.820
230 1.769 1.670 1.573 1.480 1.390 1.301 1.214 1.130 1.048 0.966 0.889
240 1.846 1.746 1.649 1.554 1.463 1.373 1.286 1.201 1.118 1.035 0.957
250 1.923 1.822 1.723 1.628 1.536 1.446 1.357 1.272 1.188 1.104 1.025
260 2.000 1.898 1.798 1.702 1.609 1.518 1.429 1.342 1.257 1.173 1.094
270 2.077 1.974 1.873 1.776 1.682 1.590 1.500 1.413 1.327 1.242 1.162
280 2.154 2.050 1.948 1.850 1.755 1.663 1.571 1.483 1.397 1.311 1.230
290 2.231 2.126 2.023 1.924 1.829 1.734 1.643 1.554 1.467 1.380 1.300
300 2.308 2.202 2.098 1.998 1.902 1.807 1.714 1.625 1.537 1.449 1.367
310 2.385 2.278 2.173 2.072 1.974 1.879 1.786 1.695 1.607 1.518 1.436
320 2.462 2.354 2.248 2.146 2.048 1.952 1.857 1.766 1.677 1.587 1.504
330 2.539 2.430 2.323 2.220 2.121 2.024 1.929 1.837 1.746 1.656 1.572
340 2.615 2.506 2.398 2.294 2194 2.096 2.000 1.907 1.816 1.725 1.641
350 2.962 2.581 2.473 2.368 2.267 2.168 2.071 1.978 1.886 1.794 1.709
360 2.769 2.657 2.548 2.442 2.340 2.241 2.143 2.049 1.956 1.863 1.778
370 2.846 2.733 2.622 2.516 2.413 2.313 2.214 2.119 2.026 1.932 1.846
380 2.923 2.809 2.697 2.590 2.486 2.385 2.286 2.190 2.096 2.001 1.914
390 3.000 2.885 2.772 2.664 2.560 2.458 2.357 2.261 2.165 2.070 1.983
400 3.077 2.961 2.847 2.738 2.633 2.530 2.429 2.331 2.235 2.139 2.051
Applicable formulas (examples on page 21):
To find actual unit heater capacity when operated at non-standard (actual) conditions:
Btu
A
= Btu
S
x Heating Capacity Factor
To select a heater capacity based on standard conditions to meet a heating capacity at non-standard (actual) conditions:
Btu
S
= Btu
A
÷ Heating Capacity Factor
Where:
Btu
S
= Capacity at standard conditions (200°F entering water temperature, 60°F entering air temperature) from Tables 19.1
through 20.2
Btu
A
= Capacity at non-standard (actual) conditions
PERFORMANCE DATA
Hot Water Conversion Tables
1-150.14