Have Saunier Duval F24E Thema Condens Combi boiler.
Since moving into house in March the hot water has been cycling hot and cold every 15-30 seconds or so.
One month back pressure would simply drop and then leak out lots through overflow requiring a top up.
Had PRV replaced and now different symptoms. Pressure will increase from about 08 to 2.9 before boiler pressure flashes and then slowly comes down to about 0.6 (slight leak from overflow but not as much as with previous PRV). Occasionally having to top up from mains.
Now when heating engineer replaced PRV he said that replacing the expansion vessel would be needed to fix pressure problem. He tried to charge it but the valve was too close to the mounting to use his pump. We tried with my foot pump but a lot of air escaped when removing valve so I'm not convinced that it successfully charged it (does it charge naturally over time?).
Anyway I'm wondering what my best plan of action should be. Could the plate heat exchanger be responsible for both the short cycling and the pressure increasing and subsequent water loss? Is it likely that the expansion vessel does just need changing rather than just charging.
The system does need a good dose of inhibitor (having continually having topped up) so do need to get to the bottom of the water loss problem in the first instance before tackling the hot and cold issue; unless they are one of the same.
Many thanks in advance. Peter.
Since moving into house in March the hot water has been cycling hot and cold every 15-30 seconds or so.
One month back pressure would simply drop and then leak out lots through overflow requiring a top up.
Had PRV replaced and now different symptoms. Pressure will increase from about 08 to 2.9 before boiler pressure flashes and then slowly comes down to about 0.6 (slight leak from overflow but not as much as with previous PRV). Occasionally having to top up from mains.
Now when heating engineer replaced PRV he said that replacing the expansion vessel would be needed to fix pressure problem. He tried to charge it but the valve was too close to the mounting to use his pump. We tried with my foot pump but a lot of air escaped when removing valve so I'm not convinced that it successfully charged it (does it charge naturally over time?).
Anyway I'm wondering what my best plan of action should be. Could the plate heat exchanger be responsible for both the short cycling and the pressure increasing and subsequent water loss? Is it likely that the expansion vessel does just need changing rather than just charging.
The system does need a good dose of inhibitor (having continually having topped up) so do need to get to the bottom of the water loss problem in the first instance before tackling the hot and cold issue; unless they are one of the same.
Many thanks in advance. Peter.
