  We present a new study of the Z~Cam-type eclipsing cataclysmic variable
AY~Piscium with the aim of determining the fundamental parameters of the system
and the structure of the accretion flow therein. We use time-resolved
photometric observations supplemented by spectroscopy in the standstill, to
which we applied our light-curve modeling techniques and the Doppler tomography
method, to update system parameters. We found that the system has a massive
white dwarf $M_{\rm WD}=0.90(4)$ \ms, a mass ratio $q=0.50(3)$, and the
effective temperature of a secondary $T_2 = 4100(50)$~K. The system inclination
is $i=74.^{\circ}8(7)$. The orbital period of the system
$P_{\mathrm{orb}}=0.217320523(8)\;\mathrm{d}$ is continuously increasing with
the rate of $\dot{P}_{\mathrm{orb}} = +7.6(5)\times10^{-9}$ d year$^{-1}$. The
mass transfer rate varies between 2.4$\times$10$^{-10}$ M$_\odot$ year$^{-1}$
in quiescence up to 1.36$\times$10$^{-8}$ M$_\odot$ year$^{-1}$ in outburst.
The accretion disk transitions from the cooler, flared, steady-state disk to a
warmer state with a practically constant and relatively high disk height. The
mass transfer rate is about 1.6$\times$10$^{-9}$ M$_\odot$ year$^{-1}$ in the
standstill. The Balmer emission lines show a multi-component structure similar
to that observed in long-orbital-period nova-like systems. Out of standstill,
the system exhibits outburst bimodality, with long outbursts being more
prominent. We conclude that the Balmer emission lines in AY~Psc are formed by
the combination of radiation from the irradiated surface of the secondary, from
the outflow zone, and from winds originating in the bright spot and the disk's
inner part.
