: I have a new anti-scald valve in my bathtub. It has two handles, one for water flow, the other to adjust the temperature.

: My Hot water is currently turned off at the source(another story). I have found that I can get almost no water to come out of the bathtub valve, not even when the temperature handle is set all the way to COLD.

: Is this normal?

Yes.
The same thing happens if you were to have hot pressure, but no cold pressure, as in a toilet flushing. The valve is set to "balance" the pressure across the faucet. So...if the hot water is turned off, it will reduce the cold flow at the same time.