Need help with Astra Mega C (Gourmet Auto)

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

#1: Post by Kaz »

I bought an old Astra Mega C with a matching grinder a few months back as my first home machine (huge overkill, I know, I know...). It had a bad rotary pump which I had rebuilt at EDCO Service in Sacramento. It makes ok espresso, but I am having a couple of problems with it:

1) When I first turn it on, sometimes it could sit for over an hour, but it would only seem like it's up to pressure. When I open the steam valve, it sputters and the pressure gauge dives to 0. The heater element then turns on and then after a while the machine finally heats up. After that everything works fine except problem (2) below. Is it a sticky valve? Which one?

2) I've built a portafilter pressure gauge and checked the brewing pressure. I only seem to be getting 5-6 bars max with the rebuilt pump, the relief valve screw on the Procon pump had little to no effect on the pressure. I had EDCO bench test the pump and the overpressure valve, they reported back that the pump was fine and set the relief valve at 135 psi (9.3 bar). I rechecked the brewing pressure on the machine and still only got about 6 bar. Then, I had the electric motor checked, and got a report back that it was perfectly fine. They also told me that these motors don't get weaker over time. Also, please note that the pump fills the steam boiler very fast, I feel like it could produce a lot of pressure during brewing too, but something is limiting it. Could it be that the computer senses that the water is not flowing (it's got a flow sensor for volumetric dosing) against the portafilter gauge and limiting the current to the electric motor? I descaled the machine and removed the group, disassembled it and checked for scale or other obstructions and found none. Do I have an issue with the computer? Or is it not an issue at all and everything works as designed?

Thanks, Kaz


#2: Post by LObin »

1. It seems you need a new vacuum breaker. You can aleays try to soak it in descaling solution or water and vinegar. These are serviceable parts.

2. This one is a little trickier. A few possibilities:

- There is potential scale in your brew path.
- Did you fully clean the dispersion plate, dispersion hole and top of the group?
- The group or autofill solenoid valve maybe be partially blocked with a loose debris.
- What kind of PF pressure gauge did you build? Did you try it on another machine to make sure it gives a proper read?
- How's your Astra pump pressure gauge behaving when A. Pulling shots? B. Backflushing with a blind filter?
- You may already so this but I would only use the manual brew button when troubleshooting.

I doubt it's the electronic board that's faulty here.

Btw, I'm currently rebuilding the same machine...

LMWDP #592