b.
In the event that both Power Supply No. 1 (24 volt DC) and Power Supply No. 2 (24 volt DC) fail, even
though AC power is present, the power failure alarm will be operated. The same silencing and ringback
features apply when generated by this means.
7.15
Condensate Drain
Each operation of the condensate drain switch is indicated by an increment of 1 on the digital readout appearing
on the front panel of the electronics drawer.
The service log of the unit indicates the specified number of operations and permits verification of the operation of
the condensate drain switch at the rate of approximately twice per calendar day.
In the event of total power failure, the readout will automatically reset to zero. This fact should be noted and the
date of the occurrence logged.
In the event the condensate drain switch mechanism fails, the following indications are available:
a.
If the condensate drain switch fails to turn the blowers off, the digital readout will not advance. Verification of
the appropriate number of shutdowns of the blower is made by multiplying the number of days since the
system was serviced by two. Digital readout should be within ten percent (10%) of that value.
b.
If the condensate drain switch turns the blower off and fails to restore it, the blower failure trouble signal will
occur on the panel. It will be indicated by both an amber blower failure lamp in the trouble group and a
common trouble signal, both visual and audible.
The condensate drain switch is a separate printed circuit board which plugs into the main printed circuit board.
Removal of this circuit board results in illumination of the timer disconnect trouble lamp and the common trouble
lamp plus the energizing of the common trouble signal plus blower shutdown.
7.16
Three switches and a fuse are located on the timer circuit board.
NOTE
Operation of these switches or replacement of the fuse is intended to be by
factory-trained servicement only and should not be attempted by the ship's
personnel. Field service operations are normally restricted to the replacement of
the entire circuit board.
7-11
