Vaillant VRC470 - not heating DHW in Cylinder

[acideraser]

Hi, some help needed please.

I have a Vaillant system: VRC470/VR61/Ecotech plus 24 / Vaillant cylinder.
Configured for two heating circuits radiators upstairs and UFH downstairs.

All worked fine until yesterday, DHW temperature was around 45 oC, then for some reason water temp dropped to 36-38 oC, heating seems working fine though.

It still shows desired water temp. 45 but not heating and under status VRC470 shows Cylinder "not charg.". I tried to change from Auto to Day, also restarted boiler with on/off button - nothing helps. Also tried Cylinder boost setting - no results whatsoever.

Seems like for whatever reason it doesn't want to heat DHW in the cylinder

Any ideas what this may be? any suggestion appreciated
Thanks

 

[acideraser]

flow temp dropped to 26 later in the day
could it be that weather compensation does not let boiler heat DHW to desired temp?

 

[St0rmer66]

Sounds like it's incorrectly installed to me. It should ignore the weather compensation when heating the cylinder, but yours sounds like it is not.

 

[oldbuffer]

Try "Party function" - its the only way I can ever get mine to heat the hot water out of the normal cycle.

 

[ScottishGasMan]

Has anyone changed the timer settings for the winter? If the Hot water time setting has been altered or is not right it doesnt matter what temp the cylinder will get to it will not fire to heat it untill its timed to come back on, any one tryed to set up timer for heating and maybe altered it for HW, as Ideally you can just leave the HW on constant and it will shut off once temperature reached.

For this set up the boiler chooses Hot water priority, and not parrallel charging, so when hot water demand is required it stops the heating circuit and runs to heat hot water ignoring the wather compensator, once charged it will revert to compensated heating for the rads.

 

[simond]

Has the HW zone valve failed? Check the output to the DHW valve inside the VR6X wiring centre.

 

[acideraser]

Thanks everyone, seems I found the problem. Indeed it was weather compensation as incorrect curve was selected.
All is working now.

cheers