A new set of low-resolution spectral and UBVJHKL -photometric observations of the symbiotic nova PU Vul is presented .
The binary has been still evolving after the symbiotic nova outburst in 1977 and now it ’ s in the nebular stage .
It is found that the third orbital cycle ( after 1977 ) was characterized by great changes in light curves .
Now PU Vul demonstrates a sine-wave shape of all light curves ( with an amplitude in the U band of about 0.7 mag ) , which is typical for symbiotic stars in quiescent state .
Brightness variability due to cool component pulsations is now clearly visible in the VRI light curves .
The amplitude of the pulsations increases from 0.5 mag in V band to 0.8 mag in I band .
These two types of variability , as well as a very slow change of the hot component physical parameters due to evolution after the outburst of 1979 , influence the spectral energy distribution ( SED ) of the system .
The emission lines variability is highly complex .
Only hydrogen lines fluxes vary with orbital phase .
An important feature of the third orbital cycle is the first appearance of the OVI , 6828 Å Raman scattering line .
We determined the hot component temperature by means of Zanstra method applied to the He II , 4686 line .
Our estimate is about 150000 K for the spectrum obtained near orbital maximum in 2014 .
The VO spectral index derived near pulsation minimum corresponds to M6 spectral class for the cool component of PU Vul .