Hi there,
I have a Vokera Syntesi 25e combi boiler, around three years old. We've had intermittent problems with pressure falling and having to be repressurised, which came to a head over the cold snap. Some days the boiler was depressurising completely overnight, giving an 04 code in the morning. Then it would go for quite a while without needing repressurising, though the hot water supply has been dwindling somewhat.
Over Christmas it seemed to be taking longer to repressurise - I wasn't hearing the gushing sound of water rushing through the filling loop. I've had the loop off and cleaned it out - no obvious issues there. Some mornings it was taking half an hour to re-ignite and repressurise - I put this down to the severe cold weather.
On Tuesday morning this week the boiler locked out with an 04 code - the first time for perhaps a week or ten days. It will not repressurise at all. I've had the filling loop open for an hour or more at a go and nothing.
I've checked the expansion vessel pressure - it's registering at about 14 psi. I've no obvious leaks that I can see on the rads.
While checking rads I noticed that there was black water coming out of two of the rads upstairs - these are the rads where there is always excess air if I do a bleed - none of the other rads seem affected.
I'm wondering if this is linked to the repressurising problem - could there be gunk from these old rads blocking the system somewhere in the boiler? If so, is this something I can get at myself and clean out? I could do with a bit of advice on what I should be looking at.
One other point - I followed some advice on this site and removed the flow restrictor. The hot water taps are flowing merrily now - just not with hot water!
Any advice or guidance would be much appreciated.
I have a Vokera Syntesi 25e combi boiler, around three years old. We've had intermittent problems with pressure falling and having to be repressurised, which came to a head over the cold snap. Some days the boiler was depressurising completely overnight, giving an 04 code in the morning. Then it would go for quite a while without needing repressurising, though the hot water supply has been dwindling somewhat.
Over Christmas it seemed to be taking longer to repressurise - I wasn't hearing the gushing sound of water rushing through the filling loop. I've had the loop off and cleaned it out - no obvious issues there. Some mornings it was taking half an hour to re-ignite and repressurise - I put this down to the severe cold weather.
On Tuesday morning this week the boiler locked out with an 04 code - the first time for perhaps a week or ten days. It will not repressurise at all. I've had the filling loop open for an hour or more at a go and nothing.
I've checked the expansion vessel pressure - it's registering at about 14 psi. I've no obvious leaks that I can see on the rads.
While checking rads I noticed that there was black water coming out of two of the rads upstairs - these are the rads where there is always excess air if I do a bleed - none of the other rads seem affected.
I'm wondering if this is linked to the repressurising problem - could there be gunk from these old rads blocking the system somewhere in the boiler? If so, is this something I can get at myself and clean out? I could do with a bit of advice on what I should be looking at.
One other point - I followed some advice on this site and removed the flow restrictor. The hot water taps are flowing merrily now - just not with hot water!
Any advice or guidance would be much appreciated.
