My Vaillant ecotec plus 837 is coming up to 6 years old. For the last couple of years following the summer period , when the central heating is needed I have had problems with the boiler shutting down, and displaying the F75 fault. This year the boiler would not run when the heating was called - although it was fine if hot water only was needed.
I read a few threads and came to the conclusion it was the Water Pressure Sensor (orange - bottom left hand side of boiler) I replaced he sensor (part number 0020059717) at a cost of £20.77 inc P&P. The boiler has to be drained, remove the clip / old sensor replace new sensor refit clip and refill. It is about a 10 minute job. Boler now runs fine.
I read a few threads and came to the conclusion it was the Water Pressure Sensor (orange - bottom left hand side of boiler) I replaced he sensor (part number 0020059717) at a cost of £20.77 inc P&P. The boiler has to be drained, remove the clip / old sensor replace new sensor refit clip and refill. It is about a 10 minute job. Boler now runs fine.
