HI all!
In my very rudimentary watering system, I have 3 sprinklers on a timer. They've been running beautifully -- until we hit heat indecies of over 105. Then, they decided it was enough.

So, my question is what causes a sprinkler to just not function?

I have a regular, fan, back-and-forth type sprinkler on one hose. It doesn't back and forth now. Just clicks.

I have a great tri-pod sprinkler that was shooting water in all the right places. Well, it just stopped moving back and forth, and is essentially putting out a putt-putt squirt.

I have a tri-pod type sprinkler that actually sticks in the ground on a spike. It also decided not to move back and forth.

Now, my water pressure remains the same, as I can tell by the fan and the on-a-spike sprinkler.

What the heck causes sprinklers to stop functioning and how can I fix it? I have an extensive Japanese Maple collection (ok, OCD collection) and take their welfare very seriously. Any ideas?

Thanks so much,
Christine