Graco Reactor H-25 Series Repair And Parts Manual page 35

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 9. If hose current exceeds 45A, see E02:
High zone current, page 9. 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
e. 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 board is bad. Replace the
temperature control assembly.
312063Z
.
heat zone by pressing
to view electrical current.
.
heat zone by pressing
Replacing Temperature Control Assembly
Modules
Before handling assembly, put on a 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. Relieve the pressure. See Pressure Relief
Procedure, page 26.
3. Refer to electrical diagrams; see Electrical
Diagrams manual. 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 Parts - Temperature Control, page
64.
7. Remove nuts and take entire temperature control
assembly to workbench.
8. Replace defective module.
9. Install assembly in reverse order.
.
NOTICE
. Disconnect power
Repair
35