Cleveland Convotherm Combination Oven-Steamer Gas 20.20 Service And Parts Manual page 53

• A request for heat is sent from terminal 3 of connector X21 on the Gas Board
(A20) to terminal 10 on connector X1 on the Steam Burner Control Module
(N21)
◊ 24 VAC is sent from terminal 2 of connector X2 on the Steam Burner
Control Module (N21) to the hot surface igniter (R20).
◊ The gas valve is energized allowing gas and air into the burner chamber to
be ignited by the hot surface igniter.
◊ The Steam Burner Control Module (N21) senses at least 1.5 micro amps
DC from the flame sensor (P1) at terminal 3 of connector X2 and sends a
signal from terminal 2 of connector X1 to terminal 11 of connector X25
on the Gas Board (A20).
• The heat circuit continues until both the cabinet set temperature and the
bypass probe (B5) are satisfied
◊ NOTE: If the set temperature is above 212 degrees F the hot air circuit
will be energized (after the bypass 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 B3 probe, 120 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 send and the steam generator reverts to the standby temperature of 190
degrees F.
f
5 With the combi in the Hot Air mode with time on the timer, the door closed and the
start switch is depressed
a The front display will include a lighted bar under the Hot Air symbol
• When the heat circuit is energized the heat symbol will be energized
• The cooking mode symbol will be energized.
• The time display will invert and begin to count down.
b The fan circuit is energized by the Control Board (A10) transmitting and
receiving a signal from terminals 5,6,7 and 8 on connector X10 to terminals 3,4,5
and 6 of connector X28 on the Gas Board (A20)
• The Gas board (A20) Transmits a signal from terminal 3 of connector X26 to
terminal 3 of connector X12 the Upper Motor Drive (U10.1)
◊ 240 VAC 3 phase is sent from the Motor board to the Oven Fan motor
(M1)
◊ Every 120 seconds the rotation of the motor reverses.
• NOTE: If the temperature is less than 212 degrees F than fan will be pulsed
on for 2 seconds every 60 seconds after the cabinet set temp (B6) and the
bypass probe (B5) are satisfied.
• The Gas board (A20) Transmits a signal from terminal 7 of connector X26 to
terminal 3 of connector X12 the Lower Motor Drive (U10.1)
◊ 240 VAC 3 phase is sent from the Motor board to the Oven Fan motor
(M1)