  In this paper we present new photometric and radial velocity data for the PMS
$\delta$ Sct star H254, member of the young cluster IC 348. Photometric
V,R$_C$,I$_C$ light curves were obtained at the Loiano and Asiago telescopes.
The radial velocity data was acquired by means of the SARG@TNG spectrograph.
High-resolution spectroscopy allowed us to derive precise stellar parameters
and the chemical composition of the star, obtaining: T$_{\rm
eff}$\,=\,6750\,$\pm$\,150 K; $\log g$\,=\,4.1\,$\pm$\,0.4 dex;
[Fe/H]=-0.07$\pm$0.12 dex. Photometric and spectroscopic data were used to
estimate the total absorption in the $V$ band A$_{\rm V}$=2.06$\pm$0.05 mag, in
agreement with previous estimates. We adopted the technique of the difference
in phase and amplitude between different photometric bands and radial
velocities to verify that H254 is (definitely) pulsating in a radial mode. This
occurrence allowed us to apply the CORS realization of the Baade--Wesselink
method to obtain a value for the linear radius of H254 equal to 3.3$\pm$0.7
$R_\odot$.
  This result was used in conjunction with photometry and effective temperature
to derive a distance estimate of 273$\pm$23 pc for H254, and, in turn for IC
348, the host cluster. This value is in agreement within the errors with the
results derived from several past determinations and the evaluation obtained
through the Hipparcos parallaxes. Finally, we derived the luminosity of H254
and studied its position in the Hertzsprung--Russell diagram. From this
analysis it results that this $\delta$--Scuti occupies a position close to the
red edge of the instability strip, pulsates in the fundamental mode, has a mass
of about 2.2 $M_\odot$ and an age of 5$\pm$1 Myr, older than previous
estimates.
