Unit will not start at all; display is blank and no lights or sounds are present.

Safety first: Use caution around electrical panels. Turn off the main breaker before tightening any connections.

• Check breaker: Inspect the dedicated breaker for the Heat Siphon in your electrical panel. Reset if tripped. If it trips again immediately, do not force it on—call an electrician or technician.
• Verify disconnect: Ensure any outdoor disconnect near the heater is in the ON position.
• Inspect internal fuses: With power off, open the control compartment and look for low‑voltage or line fuses on the control board. Replace only with identical ratings.
• Check wiring: Confirm that line wires are tight on the heater’s terminal block and that no signs of burning are present.
• Board failure: If proper voltage is present at the unit but the display remains dead, the control board power supply may have failed and will need replacement.