Warning
Warning
Caution
Warning
Operation
Reversal may be at either full or half speed; however, reversal at half speed is recommended. Reverse operation of the fan should be used sparingly and should only be used to control ice, not to prevent it. Reverse fan operation should not need to exceed 1 or 2 minutes. Monitor- ing is required to determine the time required to melt accumulated ice.
Reverse operation of fans for prolonged periods during subfreezing weather can cause severe damage to fans and fan cylinders. Ice can accumulate inside fan cylinders at fan blade plane of rotation and fan blade tips will eventually strike this ring of ice, damaging the fan blades or cylinder. Ice can also accumulate on fan blades and be thrown off, damaging fan cylinder or blades. Allow a minimum of 10 minute delay between reverse operation and forward operation during subfreezing weather to permit ice to dissipate from fan blades and fan cylinders. See Fan Drive Caution note on page 12 for fan speed change and reversing precautions.
Intermittent Wintertime Operation:
If periods of shutdown (nights, weekends, etc.) occur during freezing weather, measures must be taken to prevent the water in the cold water
Basin heaters systems will not prevent the coil from freezing.
Unless some means of freeze prevention is incorporated into your system, the tower basin and exposed pipework should be drained at the beginning of each wintertime shutdown period.
If tower basin is drained, verify that all basin heaters have been shut off either by automatic cutoff or disconnect switch.
Protection Against Coil Freezing:
Ethylene and propylene glycol solutions are the best means to protect the coil from freezing. The following table provides the coil volume for each MH Fluid Cooler model. MHF706 and MHF707 coil volumes are for both coils added together.
18
