FOR COOLING TOWER LAY-UP – AGI RECOMMENDS
COOLING LOOP GATOR®
Developed for seasonal, short-term or long-term lay-up, Cooling Loop Gator® from Cortec® Corporation protects enclosed spaces for up to 12 months. Once the bag and powder dissolve, the VpCIs (Vapor phase Corrosion Inhibitors) adsorb on all metal surfaces, reaching recessed areas and interior cavities.
DOSAGE REQUIREMENT: 1 bag treats 88 gallons system capacity
- There are 4 bags per box. This means you need 3 boxes to treat 1,000 gallons.
- Provides excellent corrosion protection during layup period
- Can be used as a corrosion inhibitor additive in the majority of water treatment programs
- Provides multi-metal protection, including galvanized steel and yellow metals (copper, brass)
- Protects inaccessible and recessed surfaces
- Does not need to be removed prior to start up
PROCEDURE FOR LAY-UP
Your customer may decide either to completely drain the system, drain the system back far enough into the building to protect from freezing, or to keep the system full and use sump heaters to prevent freezing. Whatever method is chosen, you will need to provide a procedure to protect the system.
STEP 1: PRE-SHUTDOWN INSTRUCTIONS
** Approximately 1 – 2 weeks prior to shutting down.
- DECREASE CYCLES
Decrease cycles to help purge any deposit-forming suspended solids. If adequate side stream filtration is provided, this step may not be as critical. If the last few weeks of operation are at extremely low load, increasing blowdown will help ensure that fresh inhibitor is in the system. This is especially true where chemicals are fed based on bleed or make-up water meter.
- INCREASE THE APPLICATION OF MICROBIOCIDE
Any biofilms-related microbial activity normally kept in check by the regular application of microbiocide may run rampant once the system is shut down and chemical feed discontinued. Increasing the use of antifoulant during this period will help to remove surface biofilms.
- OXIDIZING MICROBIOCIDE
Just prior to shutting down, the system should be slugged with an oxidizing microbiocide (BromMax® 7.1) at an equivalent residual of 10 – 20 mg/L free chlorine for 6 – 12 hours. We recommend using Towerkleen 142 –– 1 hour prior to adding BromMax® 7.1 –– to help eliminate any biofilms. Using oxidizing biocide will also help reduce the risk of Legionella amplification.
STEP 2: COOLING LOOP GATOR APPLICATION
- Remove and discard outer barrier bag.
- Add the water-soluble bags directly into cooling water.
- Recirculate treated water for about 10 – 12 hours to obtain good protective layer before shutdown.
- Either drain the water out (flushing lay-up) or leave treated water in cooling tower.
- After application, all internal surfaces should be covered or closed and valves shut off.
In some of the less frigid climates, cooling water systems must by on standby for those days where air conditioning is required. It is not unusual during the winter in some areas of the country to have several days dip into the thirties, followed by several days that may reach into the seventies. This type of intermittent operation can often be as difficult and frustrating as laying-up a system.
The following tips will help you deal with this difficult operation:
- When the system is not operating and there is no flow through a controller, microbiocide addition may be curtailed. Unfortunately, the water is still present in the system, and will continue to grow microorganisms, and will need to be treated.
- This is especially important when relying primarily on oxidizing microbiocides, as they will have no residual biostatic effect. Non-oxidizing microbiocides will remain in the system longer and at higher levels than in the summer months since the holding time has increased significantly.
- You must be sure that microbiocide is fed on a regular basis. If there is no flow through your controller when the microbiocide is scheduled to feed, the microbiocide will not be fed.
- Convince your customer to start the condenser water pumps on a timed schedule and correlate microbiocide addition with that schedule. This is similar to what should be done to offline systems during the summer months. Doing this will ensure the system surfaces will have adequate exposure to microbiocide at levels sufficient to control biofilm related problems.