Harris Atlas DVL400 Technical Manual page 145

Section 4 Theory of Operation
ATLAS Series™
4.6.4.4.8 Pump A Control and Status
When K1 is activated it closes the 2 paralleled contacts which supply 24Vac to X3
pin 1 and Contactor K3 coil. K3 will only be activated if the transmitter pump
interlock line is pulled low activating K7 (to opposite of position shown) and the
coolant fault relay K8 is relaxed (in the position shown) applying 24Vac to X4 pin
1. Motor contactor K3 has 4 contacts plus an auxiliary contact.
K3.1, K3.2, K3.3 are in series with the ac to the Pump Module. K3.4 is connected
between connectors X3 pin 5 and X4 pin 5 and is used to light the Pump A ON
LED, H1C on the control panel. However, the +34Vdc to light the status LED
passes through the 4 pole isolator switch on the pump module, S1, preventing an
active status LED if the isolator switch is open. The Auxiliary contact K3.98,
connected between X3 pin 6 and X4 pin 6, provides a low(ground) transmitter status
signal that will only change if the relay physically pulls in, activating the pump.
4.6.4.4.9 Pump B Control and Status
When K2 is activated it closes the 2 paralleled contacts which supply 24Vac to X3
pin 2 and Contactor K4 coil. K4 will only be activated if the transmitter pump
interlock line is pulled low activating K7 (to opposite of position shown) and the
coolant fault relay K8 is relaxed (in the position shown) applying 24Vac to X4 pin
2. Motor contactor K4 has 4 contacts plus an auxiliary contact. K4.1, K4.2, K4.3 are
in series with the ac to the Pump Module. K4.4 is connected between connectors X3
pin 7 and X4 pin 7 and is used to light the Pump B ON LED, H1E on the control
panel. However, the +34Vdc to light the status LED passes through the 4 pole
isolator switch on the pump module, S2, preventing an active status LED if the
isolator switch is open. The Auxiliary contact K4.98, connected between X3 pin 8
and X4 pin 8, provides a low (ground) transmitter status signal that will only change
if the relay physically pulls in activating the pump.
2/25/03 888-2473-001 4-45
WARNING: Disconnect primary power prior to servicing.