21 69-0643—1
Voltage At Timer Terminals
AC Voltages at
C-C Terminals Check Action
0 Vac. — System power off. — Restore power.
—Short in timer power supply wiring. — Replace wiring.
—Limit switch contacts stuck open. — Free or replace limit switch.
—Transformer supplying power is — Replace transformer.
burned out.
Up to 15 Vac. —System transformer used to power — Use additional (separate)
the timer is inadequate. transformer.
—Additional (separate) transformer — Install transformer with proper
used to power the timer has secondary voltage.
inadequate voltage.
15 to 30 Vac. —Spring fingers on thermostat not —Rebend spring fingers to a 45
making proper contact with subbase degree angle to assure proper
terminals. contact.
—Timer has failed. — Replace thermostat.