Cleveland Convotherm OEB-20.20 Service And Parts Manual page 47

• 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. Steam production takes precedence in
the combi mode.
• 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 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 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.
d After the bypass probe (B5) is satisfied then the hot air heat circuit is energized to
increase the cabinet temperature to the setting.
• 220 VAC is sent from terminal 3 of connector X12 on the Control Board
(A10) through the normally closed auxiliary contacts of K2 and K1 to the coil
of Contactor K4 until the cabinet reaches the set temperature.
◊ The contactor K4 closes and to legs of the 220 VAC is sent to the 18 KW
element (E4)
◊ The normally closed auxiliary contact of K4 opens preventing the Steam
Contactor K1 from energizing
• 220 VAC is sent from terminal 7 of connector X11 on the Control Board
(A10) to the coil of Contactor K44 until the cabinet reaches the set
temperature.