Johnson Tee frozen?

[Steve in Woodinville]

Our dishwasher stopped draining Saturday night when it was about 17F outside. It could just be a clog, but we have a Johnson Tee and I saw a comment that they can be prone to freezing in very cold temperatures. My logic is that if it froze it would be the P-trap and since it's not pressurized the ice would expand within the pipe so little risk of the pipe cracking. It seems that if the trap was frozen and we ran the dishwasher then the water would have gone into the copper drain pipe but then either shot out the outside fitting or drained back into the dishwasher, but not freeze in the copper.

Assuming it is freezing and not a plugged drain in the dishwasher, I'm thinking that the easiest solution is just wait for it to thaw out.

Any advice on that approach?
And, anyone run into a Johnson Tee freezing before?

 

[Steve in Woodinville]

Our dishwasher stopped draining Saturday night when it was about 17F outside. It could just be a clog, but we have a Johnson Tee and I saw a comment that they can be prone to freezing in very cold temperatures. My logic is that if it froze it would be the P-trap and since it's not pressurized the ice would expand within the pipe so little risk of the pipe cracking. It seems that if the trap was frozen and we ran the dishwasher then the water would have gone into the copper drain pipe but then either shot out the outside fitting or drained back into the dishwasher, but not freeze in the copper.

Assuming it is freezing and not a plugged drain in the dishwasher, I'm thinking that the easiest solution is just wait for it to thaw out.

Any advice on that approach?
And, anyone run into a Johnson Tee freezing before?

A follow up. I put a small electric heater aimed at the inside wall and waited for the outside temperature to ge above freezing. I did take enough of the dishwasher apart to get to the filter (It's an old one) and cleaned it out. No clogs. If my theory was correct that the plug was the P-trap downstream of the Johnson Tee frozen and it was now thawed it should be OK to try it again. And, Iit worked. Being patient paid off.