The WIP cooling program helps to ensure that the burner is cooled sufficiently even when it is not in operation:

• WIP normal cooling program

  When the WIP normal cooling program is active, the burner is cooled by the cooling air fan.

• WIP emergency cooling program

  The WIP emergency cooling program will be started automatically on fault or no success of the normal cooling program.

Left: Normal cooling program, right-hand side: emergency cooling program

(1)

Combustion air fan

(2)

Combustion air

(3)

Cooling/primary air fan

(4)

Cooling/primary air

(5)

Cooling/primary air pressure monitor

(6)

Cooling/primary air damper

(7)

Bypass damper

(8)

Burner

(9)

Secondary air damper

(10)

Pressure monitor combustion air

Sequence - WIP normal cooling program

1. The cooling air fan (3) is switched on.

2. The pressure monitor for the cooling / primary air (5) switches as soon as the minimum pressure in the air duct is reached.

3. The cooling/primary air damper (6) and the bypass damper (7) are opened. The secondary air damper (9) is closed.

Sequence - WIP emergency cooling program

1. The combustion air fan (1) is switched on.

2. The cooling/primary air damper (6) is closed.

3. The bypass damper (7) is opened.

4. The secondary air damper (9) is opened.

5. The pressure monitor for combustion air (10) switches as soon as the minimum pressure is reached.

Potential causes for a WIP normal cooling program fault are:

• the pressure of the cooling/primary air is below MIN, the pressure monitor switches

• the motor circuit breaker of the cooling/primary air fan has tripped

• one or more damper(s) (cooling/primary air, bypass and/or secondary air damper) are not in position for the WIP normal cooling program

The WIP emergency cooling program stays requested event if it has failed.