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When a control board requires replacement, it is important that the replacement
board gets the shared data from the old control. The primary way the replacement
control gets this information is by the memory card that should be installed on the
old control. Remove the memory card from the old control, but leave it attached to
the unit by the plastic tether, replace the control and reinstall the memory card on
the new control. If for some reason, the memory card has been damaged or is miss-
ing, the shared data from the network (air handler) will be used by the control. The
network shared data is considered a back up for a lost or missing memory card.
Never remove the memory card from the unit or cut the tether of the memory card
as it is the most effective way to transfer the shared data. If the memory card is
damaged or missing a new memory card can be ordered from Pro Stock. The unit
will operate without the memory card, but a D4 error will be displayed on the seven
segment displays.
The memory card from a different unit should never be used.
The memory cards on the primary and secondary controls of a fully communicating
tandem system are different and not interchangeable.
The dipswitches (SW5) should be turned off if the secondary (Compressor B) is
replaced. If the primary control (Compressor A) is replaced, the SW5 switches
should be in the on position.
FIGURE 11
