Question: Is there any issue on Shabbos to open the fridge door while the motor is running if this will cause the motor to continue to run for longer?
Introduction:
There are two Gemoros that discuss a situation of an action that results in maintaining the current situation:
• The Gemoro in Beitzah (22a) tells us that one who adds fuel to a candle that is currently burning has transgressed the prohibition of ma’avir (setting fire). This Gemoro is ruled by the Rambam but is not quoted explicitly by the Shulchan Aruch.
The Rosh (Beitzah Perek 2 Siman 17) explains the reason for the prohibition: “…one who adds fuel to a fire is increasing the burning time; since without adding fuel to the fire the fire would have extinguished when the fuel finished, and the increase in burning time is considered as if the person adding the fuel has lit the fire”.
From this Gemoro we see clearly that one who “extends the current situation” is considered as if having transgressed a Torah prohibition of ma’avir.
• However, in Siman 277 the Beis Yosef quotes the Gemoro in Shabbos that discusses a lit candle placed in close proximity to the door, and the Gemoro writes that Rav condemned one who opens or closes the door (because this will inevitably result in stoking/extinguishing the fire). Rashi explains that the candle is behind the door and the draught resulting from opening the door may extinguish the candle.
The Beis Yosef writes that the Rif, Rosh and Rambam rule in line with the statement of Rav. The Beis Yosef also writes that the only prohibition according to Rashi is to open the door; there is no prohibition to close the door [which will prevent the candle being extinguished because of a draught from the open door]. It also appears from several other Rishonim (Tosfos, Terumas Hadeshen, Mordechai) that there is no prohibition to close a door next to a lit candle.
The Remo (Siman 277) quotes this leniency; i.e. that it is permitted to close an open door next to a candle, which will result in the absence of a draught and consequently the candle will burn for longer.
We can see from this case that to perform an action that will result in the continuation of an existing action, there is no prohibition.
Ostensibly, these two aforementioned halochos contradict one another, since they are both situations of maintaining the current situation, and adding fuel to a burning fire is a prohibition of ma’avir, whereas preventing a candle from being extinguished is completely permitted?
There is however, an obvious difference between these two situations: By adding fuel to a fire, according to the Rosh it is considered as if performing a positive action that will result in further combustion. However, by preventing a draught that will extinguish a fire, one is merely “removing the hindrance” and consequently the candle can continue to burn. “Removing the hindrance” to allow a melocho to continue on its own accord is permitted on Shabbos.
Discussion:
Returning to opening a fridge door on Shabbos, Rav Shlomo Zalman Aurbach (Minchas Shlomo volume 1, 10) writes that it is permitted to open a fridge door while the motor is running, even though this action of opening will cause the motor to continue running for longer.
The Orchos Shabbos (volume 3, chapter 26, footnote 7) similarly writes that there is no prohibition to open a fridge door while the motor is running, because one is only delaying the time that the motor will switch off, and there is no precedent to prohibit delaying a melocho from happening. The proof he brings for this is that it is permitted to close a door to prevent a candle from being extinguished by a draught (as discussed above).
Conclusion: It is permitted to open a fridge door while the motor is running, even though this action will cause the motor to continue running for longer, because preventing the motor from switching off does not constitute any prohibition on Shabbos.