(Dec., 2013)
STULZ CyberRow Chilled Water Series Installation, Operation & Maintenance Manual
5-3
SYMPTOM PROBABLE
CAUSE
RECOMMENDATION
Air Flow Too Low
Dirty air fi lters. (Reduced airfl ow)
Clean/replace fi lters.
CW Valve
a. Temperature setpoint too high.
Adjust to correct temperature setting.
Fails to Open or Close
b. No control power to the valve.
Valve actuator wiring faulty. Check
wiring for loose connections, breaks or
shorts. Tighten connections or replace
broken/shorted wires if required.
c. Actuator failed.
Replace actuator.
System Short of Capacity
a. Low airfl ow.
1. Check fi lters. Replace as needed.
2. Check for and clear any obstructions
across or in the (supply) discharge air
stream. Clear coil fi ns of debris.
b. Low Chilled Water fl ow
1. Check for leaks. Repair and refi ll the
CW system.
2. Check for obstructions in supply/return
CW lines.
3. Check for clogged strainer
(if
applicable).
c. Supply water temperature too high
Check chilled water supply
d. Temperature setting too high
Decrease temperature setpoint.
e. Discharge air short cycling
Place air barrier between hot/cold aisles.
back to return.
EC Fan(s) Fail to Start
a. Power failure.
Check main voltage power source
input
cable.
b. Motor starter protector tripped.
Reset motor starter protector and check
amperage of motor against nameplate.
c. Control transformer circuit
Check for short circuit or ground fault;
breaker tripped.
if none, reset circuit breaker.
d. Condensate overfl ow switch.
1. Ensure unit is level.
2. Check that condensate pan is draining.
e. Defective contactor.
Repair or replace.
5.2 Troubleshooting
Turn off all power to the unit before conducting any troubleshooting procedures, unless the procedure
specifi cally requires the system to operate. For troubleshooting purposes, the system may be operated with
the electric box open by using a pair of channel lock pliers to turn the shaft of the main power disconnect
switch to the “On” position. When the switch is turned on, high voltage will be present inside the cabinet.
Exercise caution to prevent injury. Keep hands, clothing and tools clear of the electrical terminals and rotating
components. Ensure that your footing is stable at all times.
