Radiators not getting heated due to hot water priority

[johnlisbon]

Hello all,
I live in Lisbon, Portugal and having a hard time getting good advice on my heating system: Vaillant Ecotech plus boiler, Vsmart controller and 200L Junkers hot water tank. I understand the system prioritises hot water but it is to the extent that in normal operating mode the apartment never heats up as the radiators are almost never operating. I have done tests of only heating the hot water for 1 hour and then switching to hot water/heating mode and even then the system seems to continuously switch back to heating the hot water even when there is no usage of hot water.
So far my installer just says everything is "normal" but I don't believe so.
I am not a technical expert - attached are some photos of the piping of the system and would really appreciate anyone's input and advice here.
Thank you!
John

 

[John.g]

Hi John,
I think your vSmart is one of these smart controllers which fires the boiler on/off and may (even though it shouldn't) take hours to get the rads up to temperature, some, like evohome will fire the boiler continuously if the room temperature(s) is < 1.5C below the setpoint temperature and then, as the room temp approaches its setpoint, the boiler will cycle on/off very frequently.
You say that the "system seems to continuously switch back to heating the hot water even when there is no usage of hot water.", do you mean by this that the boiler actually fires when it switches back (even with no HW demand) and if so then the HW cylinder should keep rising way above its setpoint?
What model boiler do you have?
There are several posts on here re vSmart, if you havn't already done so, just write vSmart in the search box, above.

 

[johnlisbon]

Hi John.g - thanks for the hints, I will look into all of this and do some more tests and then come back here.
Much appreciated
John

 

[ShaunCorbs]

Turn the hot water to come on in the morning around 3 am until 6am eg off this will heat the tank fully and give you heating from 6am as the hot water will be satisfied

I see you have a hot water secondary pump from the bathroom?

 

[johnlisbon]

Just an update on this: as @ShaunCorbs pointed out there is a 2nd pump to deliver hot water to a bathroom which is far from the hot water tank/boiler. This is controlled by a thermostat which was set at 30deg, it seems that this pump was continuously on as the water temperature drops when doing the full circuit, and this cooler water is then returned to the hot water tank close to the tank's thermostat. Result is that the system thinks that the hot water tank needs to be continuously heated and its not giving any time to the radiators.
A technician suggested to change the 2nd pump to one controlled by time and temperature so it is only activated when we need it, such as the mornings. For now, I have turned it off to see if we can survive with just longer delivery time to the 2nd bathroom.
And as also suggested, I had programmed the vsmart to do completely different heating cycles: early morning hot water only, then heating only and the same in the evening - this works but obviously is much more complicated and seems to defeat the purpose of having an "intelligent" system.
Thanks for all the advice.