eXhausted Junior Member Joined: 10 May 2014 Posts: 2 Location: Ukraine Expertise: I love coffee
Posted Sat May 10, 2014, 7:43am Subject: Gaggia Evolution steam issue
My machine is more than 2 years old.
I have an issue with steam. First I turn on my machine, then make steam mode enable, wait until green light turn on and start to use my steam hose, but hot air comes out instead of steam. I think problem with thermostat, it doesn't heat boiler enough.
I noticed one more thing about one of 2 silicone hose in water tank. One of them is connected to pump and carries water, but second, which is connected to OPV, doesn't carry water at all. I want to know what is destination of two of them.
Did you add an OPV? The Evo does not have an OPV in OEM configuration. The second hose connects to a self fill/prime valve part 12 in the diagram. It is prone to failure. It does vent back to the tank.
You should not have air in the boiler unless you mean steam. If you open the steam valve, you should get steam if the machine is hot enough, and water if not. Open the valve/wand with the steam switch off and if you are not getting water, then the boiler is not full and primed. The SPV mentioned usually fails in a partially open position and bleeds water back to the tank. If is stuck closed and you depend on its function to keep your boiler full, that would explain air in the boiler. Most remove the valve and seal the opening, and then prime, remove water and steam to completely fill the boiler through the steam mechanism. The boiler will be almost full by running the pump through the group instead of the steam mechanism, but that could leave a little air on top.
If it is not hot enough, then you may have a steam stat issue. They can fail over time with heating and cooling cycles.
I see the same post on three forums. Not generally considered good etiquette, and can violate some rules :)
Posted Sat May 10, 2014, 11:09am Subject: Re: Gaggia Evolution steam issue
Your Evo when new will self prime. As noted, that is a poor mechanism because it will fail. It probably primed your machine well for a while, and kept it full/primed. SPV comes off of the steam valve and you get the same prime effect by opening the steam valve and turning on the pump until water exits the wand. It will be filled to the top. When you turn on the pump with the valve closed the machine will fill to the top of the upright pipe in the group, see the diagram and note the pipe up into the boiler from the group. It is not quite to the top so you can leave an air cap. I prefer to fill through the steam mechanism, valve and wand, to top off the boiler. In theory, the brew pressure might be more consistent without the compressibility of the air cap - but not sure of the size of that cap.
When you normally make steam in a SBDU machine you will need to open the valve and purge water and moisture as the water expands through the valve. "Dryer" steam then follows. If you had air on top, and if your steam stat is not heating properly, you could get air our. If the boiler is full, you should get water and/or steam when you open that valve.
No worries about the cross posts, just for future :)
fwtechwiz Senior Member Joined: 19 Feb 2010 Posts: 530 Location: Fort Wayne, IN Expertise: I live coffee
Espresso: Gaggia Evolution Grinder: Hario Skerton
Posted Sun May 11, 2014, 2:12pm Subject: Re: Gaggia Evolution steam issue
If the Self Prime valve is stuck open, and you wait for the green light to come on in steam mode, all the steam and pressure will go out the SPV, through the rubber hose and into the reservoir. No pressure will be left in the boiler. No pressure = no steam. Three things... 1. plug the SPV . It's a bad design and will eventually damage the machine.
Don't wait for the green light to come on. After hitting the steam switch, wait 30 seconds, then open and close the steam valve to flush out any water (have a pitcher under the steam wand to catch the water). Then put your milk pitcher in position to steam milk, and open the valve again. You should have plenty of steam way before the green light comes on.
Check your steam Tstat for a burned connector. That's what happened with mine when the steam tstat failed and left me with little to no steam.
I've attached a pic of the steam valve with the SPV plugged. (also modified so the steam valve stem can be removed and cleaned)
Also will post a pic of where you need to check for a burned connector.
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