Is there a problem buying a refrigerator that does not have special shabbos mode approved by a kashrus agency? ie it may have a display that I would normally just ignore like a display on an alarm system?
Not a problem. Just ignore the display
how about if it turns on the light and can’t be disactivated?
Technically it is allowed. Many people wouldn’t use it and you might scare your guests away.
Any problem with the compressor going on/off when opening the door?
Not a problem since you dont care that the compressor go on or off when you open the door. You simply want to open the door to get something from the fridge. Its the same as opening the front door of your home which is permitted even though the air conditioning may turn on or off during the process.
Regarding lights in the refrigerator.
If you know the lights will turn on when you open it, you can still use it as usual?
What is the reasoning?
Even if you know the lights will turn on. This would only be permitted where you don’t care about the light in the fridge, for example, where the light in the room is on so you don’t need the light in the fridge to see.
To understand the reasoning behind this see, Ohr Yitzchak volume 2, Siman 166.
Does this only apply to one who forgot to turn off the light before shabbat?
How about if you are by someone’s house who is less observant, and in general does make the effort to do so. Can I go ahead use that refrigerator?
Yes in that scenario you surely can open and close the refrigerator guilt free. As long as the light in the fridge is not the only light source in the room.
I don’t understand the rav’s reasoning at the end. The rav states:
וכן מותר לפתוח המקרר ואף שנדלק האור, דכיון שיש לנו ספק בהדלקת חשמל אם אסור מדרבנן או מדאורייתא, הוא ספק פסיק רישיה דלא ניחא ליה בדרבנן ומותר.
If the rav considers turning on the light a ספק איסור דאורייתא, it should be a ספק פסיק רישיה דלא ניחא ליה concerning a דאורייתא (not a derabannan). Please explain.
Also, does the rav accept the distinction between LED and florescent?
The Melacha in question (turning on a light) is a Safek D’oraita but the Issur in question (Psik Reishah D’lo Nicha Lei) is a Safek D’Rabbanan.
Regarding LEDs. Great question. It’s been discussed but nothing conclusive.
Was the Rav talking about incandescent lightbulbs being a safek d’oraita? (and therefore still okay to open a fridge with one on shabbos if you forgot to turn it on and there is other light in the room)