M
MickyMann
Hello everyone, I hope someone can help solve this one.
We've a 12 year old (at least) Worcester RSF280 Combi system (not condensing) which has, over the last couple of months, developed a "thud" seemingly in the house pipework when the CH pump starts up and it seems to be getting more noticeable.
It's not unlike water-hammer when a cold-water tap is turned off, except that it happens when the pump starts. Moreover, it isn't apparent when the system is heating the house in the early morning, it only happens when the system is hot and the room-stat is calling for cyclic off-on to maintain temperature.
The system sequence seems OK insofar as the fan and diverter operate then after a 12 second delay the pump starts (usually accompanied by a "thud") then after a few seconds the igniter starts and the boiler fires up.
The radiators have been bled repeatedly with little gas being present each time.
When cold the system pressure sits around 0.8bar and when hot, never exceeds about 1.4bar and it's lived quite happily like this for years.
I thought I'd sorted it out today when out of desperation I depressurised and part-drained the system to check the expansion vessel charge pressure and found it to be lower than the gauge could measure (<0.3bar) so I pumped it back up to about 0.6bar and refilled and re-pressurised the system; it seemed great for a while but as the system had been off for about an hour, when it'd been running a while and everything heated up, the "thud" returned.
I'm loathe to call in a professional at this stage as after talking to neighbours who've had various boiler problems (but none like this) I get the idea that many seem to fault-find by a "swop-it-and-see" routine iincurring substantial charges for unnecessary parts in the process which as a retiree I can ill afford.
Surely someone must have come across a problem like this and can advise, please help!
Mick
We've a 12 year old (at least) Worcester RSF280 Combi system (not condensing) which has, over the last couple of months, developed a "thud" seemingly in the house pipework when the CH pump starts up and it seems to be getting more noticeable.
It's not unlike water-hammer when a cold-water tap is turned off, except that it happens when the pump starts. Moreover, it isn't apparent when the system is heating the house in the early morning, it only happens when the system is hot and the room-stat is calling for cyclic off-on to maintain temperature.
The system sequence seems OK insofar as the fan and diverter operate then after a 12 second delay the pump starts (usually accompanied by a "thud") then after a few seconds the igniter starts and the boiler fires up.
The radiators have been bled repeatedly with little gas being present each time.
When cold the system pressure sits around 0.8bar and when hot, never exceeds about 1.4bar and it's lived quite happily like this for years.
I thought I'd sorted it out today when out of desperation I depressurised and part-drained the system to check the expansion vessel charge pressure and found it to be lower than the gauge could measure (<0.3bar) so I pumped it back up to about 0.6bar and refilled and re-pressurised the system; it seemed great for a while but as the system had been off for about an hour, when it'd been running a while and everything heated up, the "thud" returned.
I'm loathe to call in a professional at this stage as after talking to neighbours who've had various boiler problems (but none like this) I get the idea that many seem to fault-find by a "swop-it-and-see" routine iincurring substantial charges for unnecessary parts in the process which as a retiree I can ill afford.
Surely someone must have come across a problem like this and can advise, please help!
Mick