Safety first: Disconnect power and gas before removing covers. Do not bypass the air pressure switch; this is a critical safety device.

Inspect intake and exhaust: Check the Kripsol heater’s air intake grill and exhaust terminal for obstructions such as leaves, plastic bags, or insects. Clear any blockage.
Check fan operation: Restore power briefly and start the heater while observing the combustion fan. If the fan does not spin or is noisy, turn power off and inspect for seized bearings or obstructions. Replace the fan assembly if it will not run freely.
Examine pressure switch tubing: With power off, inspect the silicone tube between the fan housing and the Kripsol air pressure switch. Replace if brittle, cracked, or loose.
Test pressure switch: Disconnect the wires and test continuity while the fan is running (use extreme caution or have a technician perform this). The switch should close when the fan is at speed. If it does not, replace the Kripsol air pressure switch.
Final test: Reassemble, restore power and gas, and start the heater. If E08 persists, the control board’s fan/pressure circuit may be defective.

Heater displays E08; fan may start but burner does not light.

Possible Causes