Heater shows E08; blower may not start or may start then immediately stop

Safety: Turn off power and gas. Do not run the heater with panels removed except for brief testing.

• Check air intake: Inspect the combustion air intake screen on the SunHeater cabinet. Remove leaves, plastic, or debris. Ensure there is adequate clearance around the heater for airflow.
• Inspect pressure tubing: Locate the Air Pressure Switch and its silicone tubing to the combustion blower housing. Make sure the tubing is not cracked, kinked, or filled with water. Replace tubing if brittle.
• Test pressure switch: With power off, disconnect the wires and check continuity while gently applying suction to the tubing. The switch should click and show continuity. If it does not change state, replace the air pressure switch.
• Verify blower operation: Restore power and call for heat while observing the Combustion Blower Motor. If it hums but does not spin, or does not start at all, the blower or its capacitor may be faulty and require replacement.
• Reset and test: After clearing intake and verifying the switch, cycle power and attempt to start. Persistent E08 with a good switch and blower indicates a possible control board issue.