Hi, I have a 4 year old Vaillant Thermocompact 620E (pressurised conventional boiler).
1 I don't think it is working properly: it does heat the radiators and hot water but sometimes not very quickly.
2 I would like to find out exactly how it should be operating:
i.e. It has a modulating burner - should this set a heat ouput which maximises the continuous boiler water temperature while heat is needed? My boiler seems to heat quickly up to about 76 degrees C, then the burner turns off until the circulating water is down to about 51 degrees, then the heat cycle starts again. This gives an average circulating water temperature of about 63 degrees, which takes a long time to heat the house or hot water. I expected the modulator to adjust to keep the water near 76 degrees until the demand was satisfied.
3 In the part of the cycle described above where the water is cooling: Should it cool down to a particular temperature? If so what should the temperature be, and how is it set?
Or does it cool until the pump overrun timer runs out, and then starts to reheat?
4 When there is demand for both hot water and heating then the same sort of cycling occurs but the temperature limits seem to be different. Should the limits be the same independent of whether there is water demand or a heating demand or both?
5 I have recently had a British Gas first service under a maintenance agreement, but this seemed to be a very cursory activity and it did not include running the system to notice this behaviour.
6 Ideally I would like a decription of the way the boiler operates in detail so that I can check how mine compares - if it does not seem correct then I could get BG to fix it. I have emailed Vaillant support with these sort of questions but have had no response.
Thanks
Gareth
1 I don't think it is working properly: it does heat the radiators and hot water but sometimes not very quickly.
2 I would like to find out exactly how it should be operating:
i.e. It has a modulating burner - should this set a heat ouput which maximises the continuous boiler water temperature while heat is needed? My boiler seems to heat quickly up to about 76 degrees C, then the burner turns off until the circulating water is down to about 51 degrees, then the heat cycle starts again. This gives an average circulating water temperature of about 63 degrees, which takes a long time to heat the house or hot water. I expected the modulator to adjust to keep the water near 76 degrees until the demand was satisfied.
3 In the part of the cycle described above where the water is cooling: Should it cool down to a particular temperature? If so what should the temperature be, and how is it set?
Or does it cool until the pump overrun timer runs out, and then starts to reheat?
4 When there is demand for both hot water and heating then the same sort of cycling occurs but the temperature limits seem to be different. Should the limits be the same independent of whether there is water demand or a heating demand or both?
5 I have recently had a British Gas first service under a maintenance agreement, but this seemed to be a very cursory activity and it did not include running the system to notice this behaviour.
6 Ideally I would like a decription of the way the boiler operates in detail so that I can check how mine compares - if it does not seem correct then I could get BG to fix it. I have emailed Vaillant support with these sort of questions but have had no response.
Thanks
Gareth
