Fetco CBS-51H10 Technical Bulletin - page 2
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Q.) How will this change affect troubleshooting procedures for the brewers?
A.) Troubleshooting is similar for both versions. Both relays receive power from the output
of the thermostat on the blue wire when the system is calling for heat. When the relay
is energized, the circuit closes and current flows from the terminal block to the heaters.
Troubleshooting consists of using voltage and/or amperage measurements to
determine if current is flowing to the heaters only when the blue wire is energized.
There should be no current to the heaters when the blue wire is not energized.
One difference is that the SSR version opens and closes the circuit on only one of the
heater wires. The mercury relay version opens and closes the circuit on all heater
wires.
Another difference is the addition of the temperature limit thermostat, located on the
top of the tank. This component is tested simply by checking continuity through it.
For comparison, the diagrams below show both versions of a CBS-32Aap.
MERCURY RELAY VERSION
CBS-32Aap, 120/208-240 VAC
SSR VERSION
CBS-32Aap, 120/208-240 VAC