1.

HoweKool (April 16, 2010, 11:41 am) Francisco, There are some customers that use chemicals to remove white rust. However, they have to be very cautious since they use acid to remove the white rust. The issue is that the acid will remove the white rust as well as the galvanizing on the remaining parts of the unit. The best method is to mechanically remove the white rust and repassivate the Evaporative Condenser, which is discussed in the Common Section of the Operation and Maintenance Manuals found in the BAC Knowledge Center. If you still would like further information please contact your Local BAC Representative: FES-Ohio, Inc. Email: fes-ohio@baltimoreaircoil.com Phone: 513-772-8566 Thanks again for the great question!

2.

Francisco Flores (April 16, 2010, 10:05 am) What is the best approach to clean an evaporative condenser galvanized tube bundle when white rust has already developed? Mechanicaly cleaning the outside tubes wouldn't be too much of a problem, but the question is the inside which is where most of them are.

3.

Dan Kelly (March 24, 2010, 01:40 pm) I agree with your comment to Tony Chuang's question, that capacity can be either Air Side with a VFD on the tower fans or water side with varying the pump speed. Tony should check with each manufacturer to confirm the turndown possible given the configuration (counterflow vs. crossflow) and should understand that it's absolutely critical to make sure the heat transfer media is properly wetted at the reduced water flow, if that's the capacity control method he's like to employ. Evaporation to dryness may cause excessive scale build up, which may lead to maintenance issues later in the life of the unit. Tony, posting a message at 11:15pm last night - now that's dedication!

4.

HoweKool (March 24, 2010, 08:18 am) Tony thanks for the post! The capacity of a cooling tower needs to be controllable to accommodate the changes in thermal load. Modulating the airflow is the most common way of controlling the capacity. Variable speed drives, fan cycling, two speed motors and pony motors are means of regulating the airflow. Aside from air flow modulation, water flow modulation is another way of controlling the capacity of a cooling tower. However, reduction of flow below the recommended level may potentially create an uneven water distribution through the fill, causing scale build up, splash out/drift and icing. To successfully modulate the water flow while avoiding potential complications, dams may be installed in the hot water basin of crossflow cooling towers for a minimum flow of approximately 50%. For counterflow cooling towers, the minimum flow is limited by the nozzles used in the product which are based on the design flow.

5.

Tony Chuang (March 23, 2010, 11:15 pm) In cooling tower application, what is the effect on performance caused by variable condenser water flow? Is there any difference between counter-flow and cross-flow regarding the above issue? Is there any flow limitation? Thank you,

6.

HoweKool (March 23, 2010, 05:12 pm) Jason thanks for the first Post! In regards to the spray pump motor, I am assuming you are talking about a Closed Circuit Tower? Even so, there are many variables in this situation. Please provide us with the model and serial number of your unit to help us resolve this issue. Thanks again for the post and let us know how it goes once you install the spare pump.

7.

Jason Knauff (March 23, 2010, 02:42 pm) I'm wondering if anyone else has problems with the spray pump motors on their cooling towers. I have at least one rebuilt a year. It seems the top bearing that does not have a way to grease it, gets loud. I recently had one re-built and had a grease fitting installed. Hopefully this will help prolong the life of the motor. They did tell me the top bearing was bad. If adding the ability to grease the top bearing fixes it, I will post at a later date. It is my spare right now so it is not installed yet.