Electrolux enviro steam gum, stopped working. It seems to heat up properly but on pressing the trigger no steam comes out.

SOURCE: won't heat up

What sounds like is the fuse that governs the heating of the unit is either burned or not functioning. You can get a manual on how to fix that directly from feiyue yamata's site here. http://www.feiyueusa.com/Manual/FP202ELFuseChange.pdf
The problem is that if you have a psp990, it is not their item, it is a rebranded yamata so they dont have specific instructions for it. After you changed that fuse, i am almost positive you will be able to use your press again.

SOURCE: Trigger not working correctly

You might need to de-scale the unit to free the stuck valve.
Keep the unit unplugged.
Fill the unit with a vingar and water (filtered or distilled is best).
Screw the cap back on and place the unit in a sink upside down to allow the vingar and water to reach the valve.
After a few minutes press down the trigger several time to work the solution into the valve.
Hope this helps.

SOURCE: Russell Hobbs Steamglide 2200.Iron and steam

is the water in your area heavy? it may have clogged your iron with stone. soak plate in something like clr .

SOURCE: Electrolux Kelvinator - Unit on defrost

Check the defrosting sensor on the coil or the solanoid on the reversing valve.

SOURCE: My Eureka Deluxe Enviro Steamer doesn't steam, I

You will need to pour two measures of water using the measuring cup or 12 oz of water. The reason why water comes out of the bottom is because the floor cloth is too wet or you had too much water in the tank

Click on the link below to view the owners manual:

http://www.eureka.com/service/manuals/70359.pdf