Fisher & Paykel RF175W, Service Manual

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6.1.6 PC/FC Fans
There are two 12 Volt DC electrically commutated motors (ECMs). They provide the required
cooling power to both compartments. The motor speeds are controlled using a pulse width
modulating (PWM) technique. The power/control module controls the on/off of the compressor,
and the fans. The speed of the FC fan is fixed, and the speed of the PC fan is regulated using
pulse width modulation.
The freezer compartment fan will always be set at the maximum FC fan speed, with the PC fan
being adjusted to meet the requirement of that compartment. Off cycle fans (OCF) operate when
the product cycles off, with the PC fan operating at a fan speed of 3 to circulate the air in the PC to
ensure foodstuff in the crisper does not freeze.
When the compressor is turned on, provided the doors are closed, the fans will also be switched
on, except immediately following a defrost cycle where there is a delay of 30 seconds after the
compressor has started.
FC Fan (Viewed from front) PC Fan (Viewed from PC side of duct)
Diagram 6.1.6