Graco Reactor A-25 Instructions Manual page 30

Repair
Test SCR Circuit
1. Test the SCR circuit in the on position:
a. Make sure everything is connected, including
the hose.
b. Turn main power ON
c. Adjust the hose heat setpoint above the
ambient hose temperature.
d. Turn on
e. Hold down
Hose current should ramp up to 45A. If there is
no hose current, see E03: No zone current,
page 12. If hose current exceeds 45A, see E02:
High zone current, page 12. If hose current
stays several amps below 45A, hose is too long
or voltage is too low.
2. Test the SCR circuit in the off position:
a. Make sure everything is connected, including
the hose.
b. Turn main power ON
c. Adjust the hose heat setpoint below the
ambient hose temperature.
d. Turn on
Using a voltmeter, carefully measure the voltage at the
hose connector. You should not get a voltage reading. If
you do, the SCR on the temperature control module is
bad. Replace the temperature control assembly.
30
.
heat zone by pressing
to view electrical current.
.
heat zone by pressing
Replacing Temperature Control Assembly
Modules
Before handling assembly, put on static conductive
wrist strap to protect against static discharge which
can damage assembly. Follow instructions provided
with wrist strap.
.
1. Turn main power off
supply.
2. Follow the Pressure Relief Procedure, page 15.
3. Refer to electrical diagrams. See Wiring
Schematics, page 55. Temperature control
assembly is on left side inside cabinet.
4. Remove bolts that secure transformer assembly
and slide assembly to side in cabinet.
5. Put on static conductive wrist strap.
6. Disconnect all cables and connectors from
assembly. See Temperature Control Module,
page 29.
7. Remove nuts and take entire temperature control
assembly to workbench.
8. Replace defective module.
9. Install assembly in reverse order.
.
NOTICE
. Disconnect power
3A1570V