Component test function - GF83.70-P-3010SX

MODEL 216, 221 with CODE (228) Stationary heater up to Model Year 8 

Function 

When switching on the stationary heater (STH) with:

• the STH radio remote control transmitter (A8/3),
• the STH/HB [ZUH]/residual heat button (N72/1s30) (model 221) or
• the STH/residual heat button (N72/1s30) (model 216) or when the preselected time is reached

a check is made to ascertain whether a component fault was filed during the preceding heater operation (component status) or for model 221 whether there is an interlock in the STH or HB heater unit (A6) or for model 216 in the STH heater unit (A6) due to a fault or overheating.

If a relevant fault occurs then a start attempt is not undertaken, but rather a component test performed. If a fault is then no longer detected, the component status is considered OK for the next switch-on attempt.

The following components are monitored during the start and heater operation for open circuits, short circuits and flawless function:

• Temperature sensor (A6b1)
• Thermal fuse (A6f1)
• Combustion air blower (A6m2)
• Glow pin unit flame monitor (A6r4)
• Fuel preheating system (A6r5) (diesel engine)
• STH or AUH fuel metering pump (Y23) (model 221),

  STH fuel metering pump (Y23) (model 216)

• STH switchover valve (Y16)

Monitoring on model 221 is conducted by the STH or HB control unit (A6n1) and on model 216 by the STH control unit (A6).

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In the event of a fault the start of heater operation or heater operation is only interrupted when the faulty component is absolutely necessary for operation.

This is not the case for the switchover valve, therefore a fault on the switchover valve will not result in heater operation termination. Therefore, when component status is mentioned the switchover valve is not taken into consideration.

Tank content test 

The tank content is also checked when the stationary heater is started. To ensure that the information is immediately available at the start, the tank status is saved each time circuit 15 is switched off.

Heater operation is only started when a sufficient level of fuel is available.