[Equest-users] Caution Message

[Rakesh Desai]

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

 

From: Bishop, Bill [mailto:bbishop at pathfinder-ea.com] 
Sent: Tuesday, April 09, 2013 7:14 PM
To: rakeshdesai at ecpl.co.in; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] Caution Message

 

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

 



 



 

William Bishop, PE, BEMP, LEED AP | Pathfinder Engineers & Architects LLP

Senior Energy Engineer

 

134 South Fitzhugh Street                 Rochester, NY 14608

T: (585) 325-6004 Ext. 114            F: (585) 325-6005

 <mailto:wbishop at pathfinder-ea.com> wbishop at pathfinder-ea.com
<http://www.pathfinder-ea.com/> www.pathfinder-ea.com

P   Sustainability - the forest AND the trees. P   

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Rakesh
Desai
Sent: Tuesday, April 09, 2013 8:40 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Caution Message

 

Hello,

 

While running my proposed case, I am getting the attached caution message.

 

Can anyone help me to understand what it is meant and how to solve the
problem?

 

Thanks.

 

Rakesh Desai

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