With respect to
last week’s shiur on cooking in direct sunlight, readers have asked
for a final p’sak.
Some pointed out
that they are accustomed to brewing iced tea in direct sunlight.
The halacha
is that cooking in direct sunlight is permitted and therefore one
may place an egg on a piece of paper and cook it in direct sunlight.
Likewise one may place a cold cup of tea in the sun even though it
might reach a temperature of yad soledes bo.
It is prohibited to
cook on an item that is hot from the sun toldos chamah
(derivatives of the sun) such as the
sidewalk, hot sand or the hot hull of a tank.
How does
the halacha deliberate on hot water in a solar system?
It is a
rather complicated issue and we will attempt to be brief.
How It Works
Cold water enters
the hot water heater from the bottom (see diagram below) and from
there travels to the sun/solar collector. The collector consists of
several black-coated pipes, on a black background, all encased in a
sheet metal tray covered with glass, which absorbs the sun’s rays
and heats the water. The water then returns to the upper part of the
water heater. When a hot-water faucet is opened, the hot water is
released and is replaced by fresh cold water.
Several
factors must be considered
-
1)
Is water
heated in the panel considered heated in direct sunlight or
toldos chamah?![](shabbo1.gif)
2)
Is new
fresh water heated from the hot water inside the tank?
3)
Turning
on a hot water faucet causes cold water to enter the tank: is this
g’rama,
p’sik reisha
or a direct action?
-
On the one hand
water heated in the panel is heated in direct sunlight and yet
the sun alone could not heat the water to such a degree were it
not for the greenhouse effect and the various techniques used in
the panel, thus making it toldos chamah.
-
Cold water entering the tank mixes with hot water in the tank.
The hot water is toldos chamah (because it was heated in
the sun) and will heat the cold water. Making matters worse is
that, most solar heaters are equipped with an electrical element
that one turns on when there is insufficient sun, or if a lot of
water is used before the replacement water can be heated by the
sun. If the heater is turned on before Shabbos (and turned off
before Shabbos) it is very possible that hot water is in the
tank and cold water entering will be heated from toldos ha’ur
– derivatives of fire, (the water heated before Shabbos) which
is an issur d’oraisso.
-
On the one
hand, cold water entering the tank is via p’sik reisha, because
one’s direct action is opening the hot faucet, which ‘causes’
cold water to enter the tank. On the other hand, the system is
engineered to operate in this fashion and Rav
Shlomo Zalman Auerbach preferred to consider such
designs
as a direct action and not as a p’sik reisha. (Similar to
the light turned on in the refrigerator when opening the door of
the refrigerator. He was inclined to say that it is called a
direct action and not a p’sik reisha being that it was
engineered to turn on when opening the door).
So what
is the final ruling?
It is
widely accepted
to refrain from using hot water from a solar system on Shabbos,
mainly because the panel and piping heat the water and are toldos
chamah. Also, considerations such as for an ill person etc. must
be considered. One must ask one’s rav for a final ruling.
May one
use a dishwasher on Shabbos?
Obviously one may not manually operate the machine on Shabbos. The
question is whether one may set it on a timer to operate at a
certain time.
Rav Moshe Feinstein
ztz”l opposed using a Shabbos clock for anything but lights
and many follow that custom.
Conversely there
are many who do not follow that custom and set heaters and air
conditioners on timers. A dish washer though is different!
In order for the
dishwasher to operate one must shut the door – if this is not done
it will not operate. It can be compared to turning on a light switch
at a time when the power is off, which will cause the light to turn
on. The poskim prohibit such an action.
Consequently it is ossur to shut the dishwasher when
programmed to turn on.
Another possible
problem is that even if it is g’rama, there are opinions who
say that cooking via g’rama is ossur mid’oraisso
and water in a dishwasher cooks.