Twister PZ stove

[Rockhopperst4]

I bought a campingaz Twister PZ 2900 watt stove and a CV300 gas cylinder which weighs 240g. I've never used gas before (i normally use meths).

How many litres of water could i expect to boil with a 240g cylinder?

Just really need to get some idea of how long i can expect a cylinder to last me.