Cleveland Convotherm OEB-20.20 Service And Parts Manual page 44

• For the first 2 minutes 220 VAC is sent from terminal 4 on connector X11
through the normally closed auxiliary contacts of contactor K5 to the K50
contactor coil
◊ K50 contactor closes and the motor turns CW
◊ The normally closed auxiliary contacts on K50 open preventing the K5
contactor from energizing.
• For 15 seconds the motor is de-energized and allowed to coast.
• For the next 2 minutes 220 VAC is sent from terminal 3 on connector X11
through the normally closed auxiliary contacts of contactor K50 to the K5
contactor coil
◊ K5 contactor closes and the motor turns CCW
◊ The normally closed auxiliary contacts on K5 open preventing the K50
contactor from energizing.
• NOTE: If the door switch (S7) opens by the door opening, then the fan circuit
is de-energized. Then the motor will be pulsed in the opposite direction to
"break" the fan. This is to stop the fan quicker for the operator.
c The steam generator circuit is energized
• 220 VAC is sent from terminal 4 of connector X12 on the Control Board
(A10) through the normally closed auxiliary contacts of K4 to the coil of
Contactor K1 until the cabinet reaches the set temperature and the bypass
probe (B5) senses 162 degrees F.
◊ The contactor K1 closes and 220 VAC is sent to the 9.4 KW element (E1)
◊ The normally closed auxiliary contact of K1 opens preventing the Hot Air
Contactor K4 from energizing
• 220 VAC is sent from terminal 8 of connector X11 on the Control Board
(A10) through the normally closed auxiliary contacts of K44 to the coil of
Contactor K2 until the cabinet reaches the set temperature and the bypass
probe (B5) senses 162 degrees F.
◊ The contactor K2 closes and 220 VAC is sent to the 6.27 KW element
(E2)
◊ The normally closed auxiliary contact of K2 opens preventing the Hot Air
Contactor K4 from energizing
◊ If the reduced power option is chosen then the K2 Contactor is not
energized.
• When the compartment temp is reached, the steam heat circuit is controlled by
the B4 probe in the bypass tube.
• NOTE: If the set temperature is above 212 degrees F the hot air circuit will be
energized (after the by pass probe is satisfied) until the compartment setting is
reached. The steam circuit always takes precedence.
d When the condensate box is heated to 140 degrees F at the B3probe, 220 VAC is
sent from terminal 5 of connector X12 to the condenser valve (Y1) until the
temperature drops.
e When the timer counts to 0 or the core temp probe (B10) reaches the set amount
the cycle ends and the steam generator reverts to the standby temperature of 190-
degree F.