Diverter valve issue

We have a problem with our main shower. When the diverter is pulled (the diverter is on the spout) the water stops coming out of the spout, but no water comes out of the shower head.

I took the shower head off, and still the same problem. It seems to only occur on very cold mornings (overnight low was 8* last time). Once I am home from work, I test it again and everything works fine.

We recently had a new valve and faucet installed to fix a leak problem, so everything is new (2 months).

Is it possible that the valve is freezing? The bathroom is adjacent to the attic, so I could go insulate more, but I want to make sure that is the problem before I crawl up there.

Thanks!

If it works once it warms up, that's a good possibility.

Put a space heater in that bathroom and keep the room hot. See if that solves the problem. If it does, you better insulate the heck out of those pipes or you'll have a nasty flood one day.