The temperature at the wand will depend on factors like
1. Temperature of water from fresh tank
2. Length of hose from heater to wand
3. Ratio of dry to wet strokes
4. Nozzle size
5. PSI on pump
6. Temperature setting on magma.
You can put the setting to 100 degrees but if you put very cold water in, use a long hose run and keep water flowing through the heater it will never achieve that. If you put the setting to 50 degrees it should shut off and not go over that temperature which will stop you damaging delicate fabrics. You'll get a feel for it in use and what is a good balance between all the above factors.