3.
whether
the
temperature
has
been
correctly
set;
4.
whether
water
surface
is
above
the
water
level
on
the
heater;
5.
whether
tank
volume
matches
the
power
of
the
heater;
6.
whether
water
circulates
well;
do
not
put
the
outlet
of
the
pump
directly
to
the
reading
window
of
the
heater;
if
unavoidable,
please
slow
the
ow
down.
4
