  Tritium chain of the hydrogen cycle in the Sun including reactions
^3He(e^-,{\nu}_(e))^(3)H(p,{\gamma})^(4)He is considered. At the distance of 1
a.u. the flux of tritium neutrinos is equal to 8.1\cdot 10^(4) cm^(-2)s^(-1).
It is an order of magnitude higher than the flux of the (hep)-neutrinos. Radial
distribution of ^(3)H-neutrinos yield inside the Sun and their energy spectrum
which has a form of line at the energy of (2,5 {\div} 3,0) keV are calculated.
The flux of thermal tritium neutrinos is accompanied by a very weak flux of
antineutrinos (~ 10^(3) cm^(-2)year^(-1)) with energy lower than 18,6 keV.
These antineutrinos are produced during Urca processes ^3He<=>^3H. The flux of
the neutrinos of maximum possible energy (line 19,8 MeV) produced due to the
(heep)-reaction (related to the (hep)-process) is estimated
