Field Service; Cw System - Black Box CRCW-12 User Manual

Chapter 5: Maintenance
Symptom: System short of capacity.
Probable Causes/Recommendations:
a. Low chilled water flow. Check for leaks. Repair and recharge system.
b. Supply water temperature is too high. Check the chilled water supply.
c. Reduced airflow. Check filters.
d. Dirty coil. Clear coil fins of debris.
Symptom: Humidifier inoperative.
Probable Causes/Recommendations:
a. Water supply has been turned off or not connected. Connect and turn on water supply.
b. Humidifier switch is in "Off" position. Turn switch to "Auto/On" position.
c. Electrical connections are loose. Tighten electrical connections.
d. Humidifier fuses are blown. Check for overcurrent by the humidifier electrodes. Drain water from tank and refill. Replace fuses.
e. Relative humidity is above set point. Adjust humidistat set point.
f. Yellow status LED is flashing. Consult humidifier manual.
g. Water conductivity is too low. Add a teaspoon of table salt to the water through the top of the cylinder, typically only required
on initial startup.

5.3 Field Service

Repairs must be performed by a journeyman refrigeration mechanic or air-conditioning technician. Turn off power to unit at the
main power disconnect switch before attempting to make repairs.
NOTE: Do not attempt to make repairs without the proper tools.

5.3.1 CW System

If the Chilled Water system isn't cooling or if cooling is reduced, check for leaks in the system. Check for clogged water lines. If
filters are installed in the CW lines, check the condition of the filters. Clean or replace the filters if necessary.
In situations where scaling could be heavy, untreated water in the unit cooling coils may cause, over a period of time, a loss of
heat exchange capacity due to a mineral deposit build-up inside the coil. Only a qualified service mechanic should clean dirty coils.
Leak Detection/Repair
A leak in a fluid cooling system will usually form a puddle of fluid beneath the unit that can be easily seen. Visually trace the leak
up from the puddle to the area on the unit where fluid may be seen dripping.
When a leak is detected, turn off the fluid supply before attempting repairs. Adjacent piping must be thoroughly cleaned by
removing all paint, dirt, and oily film. Use a wire brush, sandcloth, or sandpaper and wipe the area with clean, dry cloths. Protect
nearby parts from heat damage by wrapping with watersoaked cloths.
For copper-to-copper (piping) repairs use SILFOS Alloy. No flux is required with Silfos Alloy. Silver solder (Stay Silv #45) and flux are
to be used on copper-to-brass or copper-to-steel repairs.
When repairs are completed, remove all traces of flux. After any repair, pressurize the system to check for leaks prior to recharging
the system.
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