Hi All,
I have a Vitodens 100-W system boiler on a vented system which operates fine however when the heating goes off a fault code 74 (low pressure) comes up. This doesn't stop the boiler starting again but comes up every time the boiler stops. It clears as soon as the heating comes back on. I have watched it whilst it stops and the pressure on the display drops to 0.2 bar for a few seconds and then goes back to 0.4 bar. Normally this sits at 0.4 bar whilst off. Anyone know what could cause the drop in pressure and how to fix this?
Thanks
I have a Vitodens 100-W system boiler on a vented system which operates fine however when the heating goes off a fault code 74 (low pressure) comes up. This doesn't stop the boiler starting again but comes up every time the boiler stops. It clears as soon as the heating comes back on. I have watched it whilst it stops and the pressure on the display drops to 0.2 bar for a few seconds and then goes back to 0.4 bar. Normally this sits at 0.4 bar whilst off. Anyone know what could cause the drop in pressure and how to fix this?
Thanks
