Heater will not start at all; display is completely blank and unresponsive.

Safety first: Use a non-contact voltage tester and follow lockout/tagout practices if available. Only work on live circuits if you are qualified.

Step-by-step checks:

• Check breaker and disconnect: Verify that the dedicated breaker for the Pahlen heater is on and that any external disconnect switch is closed.
• Inspect power terminals: Remove the electrical access cover on the heater and check that line and neutral (or all phases) are securely connected and not burnt.
• Test incoming voltage: With a multimeter and appropriate safety precautions, measure voltage at the heater's power terminals. Confirm it matches the nameplate rating.
• Check internal fuse: Many Pahlen boards have a low-voltage fuse. With power off, remove and inspect the fuse. Replace only with the same type and rating.
• Examine main switch: If the heater has a rocker or rotary power switch, test it for continuity when in the ON position. Replace if faulty.

When to stop: If correct voltage is present but the display remains dead and fuses are intact, the control board is likely defective and should be replaced by a technician.