Troubleshooting
15
5.4 Testing Relay Circuits
Using an ohmmeter, perform the following steps to check out
the relay circuits:
1. The relay circuits consist of double-pole double-throw
relay contacts brought out to terminal strips. When
the relays are operating properly, one pair of contacts
will be open with high or low level, and one pair will be
closed with high or low level. Refer to
Figures 2-10 and
5-2.
2. Relay operation may generally be heard as an audible
click when the background noise is not too high. Use
one of the methods shown in
Figure 5-3
to determine if
the relay contacts are switching.
3. Difficulty in calibration can often be traced to improper
wiring of the relay terminals to an annunciator or other
panel device. Check the wiring against the relay chart in
Figure 2-10.
Figure 5-2
Relay Circuit Operation
Figure 5-3
Relay Circuit Troubleshooting
OHMMETER
115Vac LAMP
115Vac
OR
