The following acceptance tests apply to all open- and closed-circuit cooling towers.
Prior to functional testing, verify and document the following:
(a) The conductivity controls, makeup water flow meter(s), and overflow alarms are installed as specified on the plans.
(b) Maximum achievable cycles of concentration are documented on the NRCC-MCH-E compliance document.
(c) Blowdown control sequence is available and documented in the building documents.
(d) Controls are programmed to automate bleed to the maximum cycles of concentration documented on the NRCC-MCH-E form.
(e) Controls shall be programmed not to allow blowdown until one or more of the parameters in Table NA7.6 reaches the value specified in NRCC-MCH-E.
Recirculating Water Parameters | Maximum Values |
Conductivity (micro-siemens/cm) | 2970 micro-siemens/cm |
Total dissolved solids (ppm) | 1845 ppm |
Total alkalinity as CaCO23 (ppm) excluding galvanized steel | 540 ppm |
Total alkalinity as CaCO3 (ppm) galvanized steel (passivated) | 450 ppm |
Calcium hardness as CACO3 (ppm) | 540 ppm |
Chlorides as Cl (ppm) | 270 ppm |
Sulfates (ppm) | 225 ppm |
Silica (ppm) | 135 ppm |
Langelier saturation index (LSI) | 2.5 LSI |
NA7.5.18.2 Functional Testing
Step 1: Override the makeup water valve to open until the tower water is above the maximum fill level.
Step 2: Close the makeup water valve. Verify that the overflow alarm is triggered either through an audible signal or via alert to the Energy Management Control System.
Step 3: Restore the makeup water control parameter to automatic control.