View Full Version : Fans shutdown sequence in evaporative condensers

04-07-2017, 09:03 PM
What is the best fans shutdown sequence in evaporative condensers?
I have 3 condensers with 12 fans each and more 2 condensers with 8 fans each.

Tks, Renata

05-07-2017, 12:06 AM
Could you please tell us what type or style of condenser & fans.
If you turn fan/s off is fan/s sectioned off so they don't run backwards or short circuit air.
The most effective way for power savings is to have VSD on all fans rampining up & downs together with a common set point in most cases. Very smooth operation can be achieved.

05-07-2017, 12:09 AM
From a previous thread on this subject my reply was.....

Found this semi-sales literature which explains methods and reasons of fan control...


12-07-2017, 12:56 PM
Hello Hanger1, you can see the fans and condenser in these pictures:


Very nice post, FaultCode, it will help! For sure!

12-07-2017, 10:06 PM
So installing a VSD on all fans a possibility?
Save power, smooth operation.

17-07-2017, 12:25 PM
I agree with you, but those evaporative condensers will be replace soon, then I just want to get better performance I can without invest much money.

Glenn Moore
18-07-2017, 06:43 PM
Hi Renata
The liquid outlet connection is the most important part of any condenser. The liquid exiting the condenser must always have the coldest air blowing around it to gain as much subcooling as possible. So the fans furthest away from the liquid outlet go off first and the fans nearest the liquid outlet go off last this will guarantee the best subcooling possible

19-07-2017, 12:44 AM
Hi, Glen.
I think that it is misunderstanding. You and FaultCode mentioned about air condensers, but Renata asked about evaporative condensers which typically use for industrial refrigeration. Evaporative condensers wetted by water and sequence of condenser fans is not so important. Water works as "flywheel" and pressure differential can be as low as 10-15 psig. Properly designed and installed evaporative condensers should not have subcooling at outlet. I think that not so much condenser fan sequence is important but right condenser pressure set point should chosen. Sometimes condensing pressure can float but benefits of floating are not significant.

Glenn Moore
19-07-2017, 07:11 AM
Your right but the picture of the condenser is looks like a multi fan condenser but I may be wrong as the picture is not clear on my phone!?

20-07-2017, 01:52 AM
From the top it looks like air condenser. From the side it looks like evaporative condenser. I'm not familiar with these condensers.

30-08-2017, 01:38 PM
Hello every one,

I've decided to invest in VSD, I believe it is the best option.