Now that the frame is ready, I can begin the build.
After mounting the boiler and pump etc. I tested for leaks, I am going to insulate the boiler and I didn’t want to find any leaks after the machine was fully assembled. I temporarily mounted the front gauge and rigged up the heating element and solenoid so that I could adjust the OPV again at brewing temperature. The OPV had already been adjusted but I lost that adjustment when I took it apart for the photo.
An unexpected problem was that there pool of water under the pump. It was coming from the inlet of all places, strange as that is under suction but there is a column of water in the tube at rest. I couldn’t see any holes and everything looked ok, I cut off about 10mm of the tube and reattached it - leak gone. Maybe it was due to the tube being stretched where it fits over the barb on the inlet, leaking under vibrations when the pump is operating, who knows what the problem was but it shows the value of checking everything.
Once up to temperature I started the pump with solenoid energised, adjusted OPV to 9.0 bar. No more leaks. Compared pressure readings between the on board gauge and portafilter gauge, about 1 bar difference. The portafilter gauge reads 0.5 bar at rest so that probably explains some of the difference.
Mounted SSR’s with some wiring and attached group head with some insulation under the cover.
Mounted front cover with switches and gauge, connected gauge.
I hadn’t done anything to the steam valve up to now, I found out that it squeaked when opened and had a rough action. Stripped the valve, put in a new pad seal and lubricated with Molycote 111. There are a few O rings in there and I should have ordered them with the rest of the seals. Meh, if there’s a leak I’ll just have to strip it again to replace them. Had to bend the bracket that holds the steam valve slightly to get the valve to line up with the steam knob hole. You can adjust the position of the steam valve up and down in the bracket but have to bend the bracket to get side to side adjustment.
So it’s beginning to look like a coffee machine now.