Last week, I sanitized the fresh water system on my 2011 Keystone Montana 3400RL 5th Wheel. Now this cold snap will bring temps down to 25 degrees tonight. I used the Thetford system to sanitize ...
I think you're fine. Turn up the heat a little more and open the cabinet doors to let more heat to the water lines and tanks. We did several nights at about 22D without a problem.