Chapter 4: Product Maintenance
• Replacing PSUs, page 65
• Replacing Fan Modules, page 69
Replacing SG4500 Series Modules
The SG4500 Series allows on-site, hot-swap replacement of both its dual power supply units
(PSUs) as well as any of its 3 cooling fan modules. This chapter describes the onsite removal and
installation of both PSUs and fan modules.
4.1. Replacing PSUs
The SG4500 Series has dual hot-swappable PSUs, both of which supply power in normal,
redundant operation. As described earlier, the appliance will operate correctly with only one
power supply but that configuration provides no redundancy.
Single PSU Operation
The SG4500 Series does not need both PSUs fitted. The appliance can operate correctly with just
one PSU fitted. If this is the case, the second PSU slot should be filled with a special
PSU Filler
Module
. This module also has the effect of disabling the PSU failure alarm which will be
automatically activated if one PSU slot is left completely empty.
Tip: Any slot can be used for a single PSU
In a single PSU configuration, it is not important which of the two PSU slots contains the
PSU and which contains the Filler Module. Either slot can be used for either function.
Dual PSU Operation
When both PSUs are fitted, PSU redundancy is provided. If a PSU fails then the security gateway
will continue to function and the faulty PSU can be changed on-site through a simple procedure
provided that a spare PSU is available.
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