My Frigidaire mini (2.5 cubic ft) thermostat seems to be the culprit in not keeping ice frozen. I've You Tubed the problem took out the old part which is WPF 21 rated: 250V, 6A, 50/60 Hz. The video is old and WPF 21 is no longer available. Can I use WPF 22 or 20 safely and would either work...