•
120 VAC is sent from terminal 1 of connector X13 on the Control Board
(A10) to the Generator Pump (M4).
•
As the water level drops below the probes the fill solenoid (Y3) will energize.
This rocking of the water will help flush scale from the generator.
•
Then the pump will be energized again
•
When the condensate box is heated to 140 degrees F at the B3probe, 120 VAC
is sent from terminal 5 of connector X12 to the condenser valve (Y1) until the
temperature drops.,
b
The display will show the set temperature and set time.
c
The Control Board (A10) will check the water level by looking for a ground at
terminals 1 and 2 on connector X15. These are connected to the high and low
probes (B1) in the steam generator.
•
If the ground is not found 120 VAC is sent from terminal 7 on connector X12
on the Control Board (A10) to the fill solenoid (Y3)
•
The fill solenoid opens and the generator is filled until both probes are
grounded.
◊
If the top probe becomes ungrounded for more that 5 seconds the fill
solenoid (Y3) will energize.
◊
If the bottom probe becomes ungrounded the combi will fill immediately
and the combi will not heat
d
When the terminal 2 on connector X15 is grounded, the Control Board (A10)
transmits and receives 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) begins the steam generator heat circuit
◊
A signal is sent from terminal 8 of connector X24 to terminal 4 of
connector X2 on the Steam Power Burner and Fan Control (U21) selecting
the set speed of the combustion blower.
(a)
When this speed is attained the signal is sent from terminal 2 of
connector X2 on the Steam Power Burner and Fan Control (U21) to
terminal 9 of connector X24 on the Gas Board (A20)
◊
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)
(a)
24 VAC is sent from terminal 2 of connector X2 on the Steam Burner
Control Module (N21) to the hot surface igniter (R20).
(b)
The gas valve is energized allowing gas and air into the burner
chamber to be ignited by the hot surface igniter.
(c)
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 steam generator heat circuit continues until 190 degrees F is detected
from the Steam Generator probe (B4) at terminals 1 and 2 of connector X17
on the Control Board (A10)
4
With the combi in the steam mode with time on the timer, the door closed and the
start switch is depressed
67
