Chromalox MaxPac, User Manual, Page: 32 / 44

30
8
Troubleshooting
READ AND UNDERSTAND BEFORE
CARRYING OUT THE WORK DETAILED BELOW
The following guidelines cover most of the common problems that could occur with the MaxPac. They are
not intended to be, nor can they be, absolutes to cover every possible failure.
Problem
Note: Heater load must be conntected to Test.
No Power or unbalanced power to the load.
If Demand Light is “
Off”
1. Check incoming line power. Verify that fans are running
2. Check the instrument power.
3. Check the fuse on the main board.
4. Verify the input signal.
5. Check that remote stop J3 - 3 to 4 is open.
6. Check that the J2 - 4 to 5 is Jumpered.
7. Verify that heat sink is not in over temperature mode.
If Demand Light is “ On”
1. Check the connections to SCR trigger board.
2. Check the power fuses (I
2
t).
3. Look for damage on the trigger board.
Observation Possible Root Cause
LD3 – SCR1 light is ON and Alarm relay engaged Shorted SCR1
LD4 – SCR2 light is ON and Alarm relay engaged Shorted SCR2
LD5 – SCR3 light is ON and Alarm relay engaged Shorted SCR3
LD3 – SCR1 light is blinking and Alarm relay engaged Missing phase or phase error, SCR1
LD4 – SCR2 light is blinking and Alarm relay engaged Missing phase or phase error, SCR2
LD5 – SCR3 light is blinking and Alarm relay engaged Missing phase or phase error, SCR3
Over temp output conducts, Alarm relay engaged,
and heater output still functions
Heat Sink Temperature greater than 200˚F (93˚C)
detected but all outputs less than 212˚F (100˚C)
Over temp output conducts, Excessive temperature
of heat sink and Alarm relay engaged, heater output
still functions
Heat Sink Temperature greater than 200 ˚F (93˚C)
detected but all outputs less than 212˚F (100˚C)
Diagnostics with Safety Cover Removed
Observation Possible Root Cause
Heartbeat LED not blinking Loss of electronics AC power. Check fuse.