Fuji Electric FRENIC-HVAC User Manual page 652

[ 29 ] PVn External PID feedback wire break
Problem: The PID feedback wire is broken.
PVA External PID control 1 feedback error
PVB External PID control 2 feedback error
PVC External PID control 3 feedback error
Possible Causes
(1) The PID feedback signal wire is
broken.
(2) PID feedback related circuit
affected by strong electrical noise.
(3) The function code setting is not
appropriate.
[ 30 ] Pdr Dry pump protection
Problem Drought conditions were detected during PID control.
Possible Causes
(1) The water level in the water tank
has dropped to the drought
position.
(2) Water is leaking from the pipes
or pump system.
(3) The function code setting is not
appropriate.
What to Check and Suggested Measures
Check whether the PID feedback signal wires are connected
correctly.
 Check whether the PID feedback signal wires are connected
correctly. Or, tighten up the related terminal screws.
 Check whether any contact part bites the wire sheath.
Check if appropriate noise control measures have been implemented
(e.g., correct grounding and routing of signal wires, communication
cables, and main circuit wires).
 Implement noise control measures.
 Separate the signal wires from the main power wires as far as
possible.
The external PID control feedback error upper limit (J529, J629,
J679) settings are too high.
 Review the set feedback value.
The external PID control feedback error lower limit (J530, J630,
J680) settings are too low.
 Review the set feedback value.
What to Check and Suggested Measures
Check whether the water level in the water tank is sufficient.
 Check whether the correct amount of water is being supplied to the
water tank.
 Check whether the motor-operated value is closed.
Check whether water is leaking from the pump system or from around
the pipes.
 Check whether water is leaking from the pump itself.
 Check for cracks in the pipes and so on, and check whether water is
leaking from the connections between pipes. Increase the
tightening at the pipe connections.
Check whether the drought protection (detection current) (J177, J277)
setting is too high.
 Review the set current value.
Check whether the drought protection (deviation) (J178, J278) setting is
too small.
 Review the set amount of deviation.
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