Real time QtCharts block the UI after few minutes

[r.brue]

Hi,I am cross-programming a Qt application for an embedded device (iMX6 QUAD + 1GB RAM). I am trying to create a QApplication which uses QChart classes for generating real time charts. These charts must run and refresh for a maximum of 10 hours but I am facing the problem that after few minutes the UI is completely blocked.
What I am doing is creating a QThread which sends signals with the new data to the QMainWindow which contains few QCharts that must be refreshed. The QCharts have a X dimension that when there is more data, the chart must scroll right.
My appending function core is composed by the following:

if(reachedMaximumRight){
    QPointF p(xIndex, dataY);
    m_series[sIndex]->remove(0); 
    m_series[sIndex]->append(p);
    m_axisX->setRange(xIndex-maxXElements, xIndex);
}else{
    QPointF p(xIndex, dataY);
    m_series[sIndex]->append(p);
}

What am I doing wrong? It seems that the chart doesn't removes old points and the UI cannot handle such heavy chart but I am not sure.
PS: I have found a library called QWT, could it suit better for my purposes?

PPS: I have followed the basic dynamic chart example (here)