The FC-Fan-w/Dampers curve determines fan power as a function of part load. I'm guessing that the system that you have applied this curve to has a MAX-FAN-RATIO greater than one, which is causing the output of the curve to exceed the OUTPUT-MAX.
The OUTPUT-MAX for the curve is 1.05, as shown on the warning message and in the curve properties dialog box (see below).
The warning message is showing that the fan power is being limited to the maximum allowable by the curve. The flow through the supply fan is exceeding 100% of design value, but the power is not increased accordingly.
You can reduce the MAX-FAN-RATIO to 1.0 assuming the fan is limited in that way. Alternatively, you could increase the curve OUTPUT-MAX, either in the library curve or by creating a new curve as I have shown below. This will extrapolate values of the curve beyond their intended range, so the accuracy of the fan power at greater than design flow may be a little off, but it is certainly better than not making any changes.
Your caution message showed output of 1.372, so you would have to increase your OUTPUT-MAX to 1.4 or higher. That might make the caution message go away, but doesn't address the reason that your fan part load is so high. I don't know what it could be.
Note that "caution" and "warning" messages are not as critical as "error" messages. If you post your .inp and .pd2 files, someone may open your model and take a look.
Rakesh,
The FC-Fan-w/Dampers curve determines fan power as a function of part load. I'm guessing that the system that you have applied this curve to has a MAX-FAN-RATIO greater than one, which is causing the output of the curve to exceed the OUTPUT-MAX.
The OUTPUT-MAX for the curve is 1.05, as shown on the warning message and in the curve properties dialog box (see below).
The warning message is showing that the fan power is being limited to the maximum allowable by the curve. The flow through the supply fan is exceeding 100% of design value, but the power is not increased accordingly.
You can reduce the MAX-FAN-RATIO to 1.0 assuming the fan is limited in that way. Alternatively, you could increase the curve OUTPUT-MAX, either in the library curve or by creating a new curve as I have shown below. This will extrapolate values of the curve beyond their intended range, so the accuracy of the fan power at greater than design flow may be a little off, but it is certainly better than not making any changes.
Regards,
Bill
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William Bishop, PE, BEMP, LEED AP
Bill,
I tried to reduce the MAX-FAN_RATIO to 1.0 but the caution message propped
up.
As suggested by you, I changed max output ratio to 1.20 in the curve but
received the attached message.
What should be next step?
Rakesh
Rakesh,
Your caution message showed output of 1.372, so you would have to increase your OUTPUT-MAX to 1.4 or higher. That might make the caution message go away, but doesn't address the reason that your fan part load is so high. I don't know what it could be.
Note that "caution" and "warning" messages are not as critical as "error" messages. If you post your .inp and .pd2 files, someone may open your model and take a look.
Regards,
Bill