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VFLPG / VFL / VTL / VRA
Maintenance
1. Normally, no maintenance is needed. A periodic function check, and re-tightening of the power
terminals, must be carried out at least once a year.
2. To maintain the insulation characteristics of the heating coils, they must be activated for 24h,
at least every 3 months.
Overheating
If the manually reset cut-out has tripped, the following must be considered:
1. Switch the power supply off.
2. The lid of the heater may only be opened by qualified and authorized personnel.
3. Carefully investigate the cause of the tripping of the cut-out.
4. When the fault has been rectified, the overheating cut-out may be reset.
Troubleshooting
●
Check that the airflow through the heater is sufficient. The airflow is insufficient if the yellow LED on the PCB
is lit up, alternatively the airflow might be sufficient but too tubulent for the electronics to sense the airflow
correctly and then the yellow LED will remain lit up and the loss of heat will also remain. However, the airflow
sensing device require a few minutes to heat itself after the power supply has been switched on. During that
period of time the yellow LED will remain lit up, even though the airflow through the heater is sufficient.
-MQEM
/
-MQEML
● Check that the sensor is of the correct type and that it is terminated correctly. (See p. 17-19).
●
Check that the correct function is selected for the controller (Pulser/TTC). (See p. 14-15).
●
Check the resistance of the sensor and the set value potentiometer.
Disconnect them from the terminals before any measurements are taken.
Sensors for 0...30°C should have a resistance of 10k @ 30°C, 11. k @ 20°C and 15k @ 0°C.
The external set value potentiometer should have a resistance of 0...5k .
Full heating without control
●
Strap/short-circuit the terminals #15 and #18.
If this results in the heating now being turned off, then the fault is in the external sensor circuitry.
If this doesn't turn the heating off and no LED is lit up on the PCB, then there may be a short in a triac.
No heating
●
Check that there is mains voltage at the heater supply terminals, and that the manual reset overheating cut-out,
has not tripped.
●
Check the interlocking devices, fuses, breakers, etc.
●
Disconnect the sensor from the terminals.
If the heater starts now, then the fault is in the external sensor circuitry.
Otherwise, the fault is in the controller (Pulser/TTC).
-MQX
/
-MQXL
/
-MQY
● Make sure that the control signal has the correct polarity.
Full heating power but no regulation
●
Disconnect the control signal wiring and strap/short-circuit the control signal input terminals.
If this results in the heating now being turned off, then the fault is in the exitation signal.
If this doesn't turn the heating off and no LED is lit up on the PCB, then there may be a short in a triac.
No heating
● Check that there is mains voltage at the heater supply terminals, and that the manual reset overheating cut-out,
has not tripped.
●
Check the interlocking devices, fuses, breakers, etc.
● Disconnect the control signal wiring and connect a 9V battery-cell or another suitable voltage source as an
excitation signal, if the heater is meant for 0...10V / 2...10V / PWM.
If the heater is meant for 4...20mA a 470 resistor has to be connected in series with the 9V battery-cell
to be used as an excitation signal.
If the heater doesn't start now, then the fault is in the regulator (Pulser/TTC).
/
-MQYL
/
-MQC
/
-MQCL
Ω
Ω
Ω
7
Ω
/
-MQP
/
-MQPL
5
Ω
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