Checking and Replacing the Battery
The real-time clock circuitry is powered by a single CR1220 lithium-ion battery. This circuit is
responsible for maintaining the date and time settings while the GDCP-Touch does not have
power. If the date and time settings reset after a power cycle, the CR1220 battery may need to
be replaced.
With power to the control panel off, pry the battery from the holder in the back of the display
board. Use a voltmeter to measure across the top and bottom of the battery. If the voltage is
not reading near 3 V, the battery is considered “dead” and needs to be replaced. Use only
CR1220 batteries.
Checking and Replacing Fuses
All of the circuit boards are protected by time-lag TR5 fuses. They are UL rated at 250 VAC,
and manufactured by Littelfuse, series 374.
There are 5 fuses on the relay board. The main fuse is located in FH1 and protects the entire
board. This fuse has a rating of 1.0 Amps.
Each pair of control relay contacts are protected by a TR5 time-lag fuse rated at 5.0 Amps.
These fuses are located in FH2 through FH5, and can be found along the bottom edge of the
relay board next to terminal strips TS3 through TS6.
Test these fuses by switching power off and removing them from their holders. Measure for a
low value of resistance across the pins. Replace any fuse that does not have a resistance
reading near 0 Ω. Always replace fuses with one having the same ratings and characteristics.
Two more TR5 time-lag fuses protect the input circuitry of the sensor board. The fuse located
at FH1 is rated at 1.0 Amp while the fuse located at FH2 is rated at 0.250 Amps. Test each
fuse for resistance and replace if the reading is not near 0 Ω.
IOM03
Rev 1.1 – May 18, 2021
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