Despatch RBC1-50 with Protocol Plus - Manual (Page 38)

34
Difficulty Probable Cause Suggested Remedy
Improper airflow Fan motor failure
Fan wheel seated too low on
fan shaft
Unbalanced fan wheel Replace fan motor.
Adjust fan wheel for 3/16" clearance between
wheel and inlet ring.
Replace fan wheel.
Excessive
vibration Dirty fan wheel
Unbalanced fan wheel Clean fan.
Replace fan wheel.
Oven will not
control at
setpoint High limit set too low
Control malfunction
SSR malfunction
Air friction of recirculation fan
Damper motor (exhaust) not
responding Set the high limit higher
Replace control.
Replace SSR and/or check control output voltage.
Open fresh air vent. Unit will not control below
minimum operating temperature with vent closed.
Check tuning parameters.
Damper motor
(exhaust) not
responding Linkage binding
Motor not working
Improper tuning parameters Observe and correct linkage.
Check supply and signal voltage.
Check tuning parameters.
Liquid nitrogen
(LN
2
) not cooling
Solenoid valve not responding
Improper tuning parameters
Tank empty or valve is to the
OFF position
Pressure regulator set too low Check supply voltage and control output. Replace
valve.
Check tuning parameters.
Check liquid nitrogen (LN
2
) supply and valve
position.
Adjust regulator to 35PSIG maximum.
Heater does not
shut down until
temp. reaches
the High limit
setting Control malfunction
SSR malfunction Replace control
Replace SSR
Nitrogen (N
2
) not
flowing correctly
Tank empty or valve is to the
OFF position
Pressure regulator set too low
Flowmeter incorrectly set Check nitrogen supply and valve position.
Adjust regulator within the acceptable range of the
flowmeter.
Adjust flowmeter to the desired flow rate.