FAA MMEL Rev.#16, 2009-09-12m from TCCA website
here
30 ICE AND RAIN PROTECTION
-11-1 Wing Anti-Ice Systems (C)
2 installed
0 required for dispatch
(M) May be inoperative provided:
a) Associated valve is locked closed,
b) Wing anti-ice control switch remains OFF, and
c) Airplane is not operated in known or forecast icing conditions.
reformatted from the somewhat tortuous MMEL format.
There's no MMEL item specifically for the valve, it's just the systems as a whole.