TM 5-3610-285-14
(a)
Solenoid valves L1, L2, and L3 control water flow through the developer heat exchanger and into the wash tank.
(b)
When cold wash water is flowing, it takes 1/3 gal/min (1.26.liters/min) through the heat exchanger to control the
developer temperature. When warm water is flowing, it takes 1 gal/min (3.8 liters/min) through the heat exchanger to
control the developer temperature.
(c)
The solenoid valves operate as follows:
Solenoid Valves
Processor
L1 L2 L3
Warm-up
Developer is not at the desired
operating temperature
ON
OFF
OFF
Operating at the desired temperature
cold wash water not in standby mode
ON
OFF
ON
Operating at the desired temperature
cold wash water in standby mode
OFF
OFF
ON
Operating at the desired temperature
warm wash water in or out of standby
mode
OFF
ON
ON
(d)
Developer temperature control circuit is involved with the water solenoids in the following way:
When the processor is first turned on, water must flow to fill wash tank, but the warm-up time is shorter if no water flows
through the heat exchanger. To fill wash tank without sending water through heat exchanger, solenoid valve L1 opens as
follows:
1
U3 on circuit board 1000 provides a reset pulse to U2A and U2B. This results in a high at pin 10
of U2B.
2
Transistor Q1 on circuit board 1000 is turned on and a WARMUP RESET low is provided to U1,
pin 14, on circuit board 500. This results in a low at pin 1 of U6.
3
A low also results at pin 8 of U5.
4
Pin 10 of U5 goes high and provides a high to pin 6 of flip-flop U9. With a high on pin 6 and a
low on pin 4, the Q output (pin 2) of U9 goes low, turns on Q3, and actuates relay K602. Relay K602 provides power
to solenoid valve L1 when the thermostat THS2 is normally closed. (This is the case with cold wash water.) With
warm wash water, LI is powered during warm-up by THS2, normally open, and relay K1001, normally closed.
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