Reply To: using hot water from tank on shabbos

I’ll bli neder look a little later (I found it: http://hebrewbooks.org/pdfpager.aspx?req=40815&st=&pgnum=316&hilite=), but R’Moshe doesn’t see a tzad heter.

http://hebrewbooks.org/pdfpager.aspx?req=919&st=&pgnum=43&hilite=