Hello, I have had my rocket for almost 2 years now, and over the past week it has started leaking out of the little circle thing on the front when brewing a shot. I think the knob is the 3 way solenoid. But yea basically water usually only come out of there after I put the lever back up when my shot is done but now water comes out during the whole brew cycle. I have always used tap water so I'm wondering if this could be due to scale build up? I will include a photo

Edit: I looked at my old post and I guess this little nub is the thermal expansion valve, so that is where my leak is from, not the 3 way solenoid

It may also be worth noting that the machine doesn't seem to come fully up to temp anymore, Eric's group thermometer reads about 195 f after an hour of warming up, where it used to be like 205-207 after an hour

that is rotary pump machine, right?
then (and only if it is rotary pump) your bypass on pump could got "stuck" or doesn't work properly anymore leading to higher pump pressure = leaky OPV (I see that quite often, brew circuit descale and cleaning & lubrication of bypass piston helps)
or
your OPV is faulty and leaks on lower pressure than it should

start by checking your pump pressure with blind filter, it should be less than 11-12 bar (the OPV should keep the pressure under 12 bar). if it hits high pressure, try to tune-down your pump bypass.

A leaking expansion valve (aka OPV) would cause that symptom. That valve connects to the little knob above the drip tray via a plastic hose. When the machine heats up from cold, expanding water inside the HX causes the expansion valve to open, and you may see some drips from that knob. The valve is adjustable, but in your Evo V2 with a rotary pump you just leave it at the factory setting which is probably around 12 bar, maybe higher. The valve's purpose here is primarily to protect the HX from very high static pressure when the water expands. (There is no air or vapor inside the HX, so a little thermal expansion of the incompressible water can cause really high pressure.)

While brewing you should see no water coming out of that knob. As kolu said in the previous post, check your pressure gauge on a backflush blank filter and if it's going over 10 bar adjust the pump down a little. If you're lucky, the only thing wrong here is that the pump adjuster's locking nut came loose and the pump adjustment went high. An easy thing to fix (see video I linked below.)

A possible but less likely cause of flow at that knob while brewing might be a bad boiler fill solenoid. This can cause the boiler to overfill when the pump is on, and the excess water would come out the boiler safety valve which also has a plastic tube running to that knob. One way to rule that possibility out is to lock in a backflush blank, open the steam wand a little, and raise the brew lever for 30 seconds or so. If water rather than steam starts shooting out then you know you have a bad fill solenoid causing the boiler to overfill.

If you do have a leaking expansion/OPV , it can allow air into the system, which can cause a thermosyphon stall. This could be causing your low idle temperature. You can disassemble, inspect, and clean that valve, but if you do that be sure to measure or mark it before you unscrew the top part so that you can reassemble to the same adjustment. If it's leaking it may be wiser just to replace it with a new one. (Rocket Expansion Valve, part #C229900911, costs $30-$40 USD)

If your expansion valve is malfunctioning due to scale fouling, then there may be other scale related problems. You can pull your group mushroom and look for signs of scale there, but I think if you are on the Seattle water utility you should not be seeing a scale problem, even after 2 years of tap water. (Seattle's Tolt and Cedar river sources are both low hardness and low alkalinity.)

Here's a nice video from WLL that shows where that expansion/OPV is, and also explains how to adjust the pump pressure: http://www.youtube.com/watch?v=KJwq4wR8vds