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The troubleshooting tips in the following table may also help diagnose a servo valve or absorber problems.
Troubleshooting Chart
Symptom Possible Cause
Absorber does not load • Insucient water supply
• Servo Valve spool loose or incorrectly indexed
• Absorber rotor or stator bad
• Normal condition: No water will ow through the PM absorber in NORMAL
conguration, unless the engine RPM >500
Control unstable
(manual mode)
• Engine not running smoothly
• Severe ignition noise
• Insucient water supply
• Capacity of absorber exceeded
• Servo Valve spool loose or incorrectly indexed
• Too much water owing through the absorber
○ Check ValPos value and ServIn position when controlling to EngSpd.
Typical ValPos range is from 1 to 5.
○ Optimum ServIn position is 60-80% for start RPM setpoint
▪ Too low = ValPos too high, decrease ValPos
▪ Too high = ValPos too low, increase ValPos
• Water pressure too high or low
○ Optimum pressure setting is between 50-80 psig
• Water backing up in outlet port of absorber or horn-of-plenty
○ This creates backpressure on the system and aects control
• Check inlet/outlet water temp delta T; optimum delta T is 60-100 degrees F
Control unstable
(EngSpd mode); RPM
rate inconsistent with
selected rate
• Check in Manual mode for control problems
• PID control parameters incorrect; load correct le (.ccp)
• Too much water owing through the absorber
○ Check ValPos value and ServIn position when controlling to EngSpd.
Typical ValPos range is from 1 - 5.
○ Optimum ServIn position is 60-80% for start RPM setpoint
▪ Too low = ValPos too high, decrease ValPos
▪ Too high = ValPos too low, increase ValPos
• Water pressure too high or low
○ Optimum pressure setting is between 50-80 psig
• Water backing up in outlet port of absorber or horn-of-plenty
○ This creates backpressure on the system and aects control
• Electronics failure in sensor box
7.0 Troubleshooting
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