In this particular situation, the only tubing that is new is that leading to the Sirai pstat connection, as far as I can tell. So then, that tubing, by itself, locates and supports the pstat. As just a simple example, suppose that tubing were 1/4" longer or 1/4" shorter, would it make access to something else easier? Or is this really relevant in your particular situation?

I do know this - it is a lot easier to change before you solder than after.

erics wrote:I do know this - it is a lot easier to change before you solder than after.

Oh yes, that was planned. I'll also support it on the frame. I'd already accessed the Sirai document and will mount it upright with the adjustment screw facing forward because I'll want to be able to adjust the PSTAT as I move from one coffee to another, especially if sampling different levels of roasts on different days. If I have to descale a little more often, so be it.

Can fully support the decision to scrap Sopac pstat. My Bezzera Family was born with an identical one. Its got a very wide deadband and the lowest setting is 0.8 (on) - 1.2 bar (off). Replaced mine with a Mater (in like ten minutes) and espresso quality increased significantly after the temperature was adjusted downwards.

If I were starting again that's probably the PSTAT I would use or something very much like it. It's a quicker fix to just plug it in instead of figuring out how to fit the Sirai, but since I have a Sirai and there's pipe coming to me I'll complete it that way.

That makes a lot of sense. Also find the Sirai pstat to be better looking in a larger machine with plenty of space inside.

An advantage of the Sirai is it has an adjustment screw that I will face forward* to access it through an opening in the front cover that is sealed by an insert. This will allow adjustments without having to go under the machine, which is quite heavy, especially if filled with water.


* Lots of discussion has already occurred about which way to position the Sirai. Their documentation tells it can be mounted in any direction but the one in which it is mounted horizontally reduces scale accumulation. I'm choosing the best compromise, I believe, for my planned usage pattern.

Gary, though it may be inconsequential, mounting the Sirai at a very slight angle may be beneficial. The screw could still be accessible but the slight angle could help water drain back from the pstat so you don't have water sitting in the pstat. I bet Doug would know if this is worth considering or not. Maybe you've even already thought of this.

Thanks, jonny. Looking at the Sirai, I am thinking horizontal or not. For now I will choose vertical. Using the machine will quickly tell me if I need to do frequent adjustments. If those are unnecessary I'll remount it in horizontal position. If I find myself adjusting it frequently and it scales quickly it may be time to have Ray coach me on doing a PID. For now I want to get it working. At worst I'll need to descale the Sirai earlier than expected.

drgary wrote:If I find myself adjusting it frequently and it scales quickly it may be time to have Ray coach me on doing a PID. For now I want to get it working. At worst I'll need to descale the Sirai earlier than expected.

I'm here when you are ready to PID that thing!

I think learning to operate the machine in its P-stat (i.e. "stock") state is a good idea first however. Not only will that give you a great feel for the machine, but it will make you appreciate a PID if you elect to install one down the road.

Ray

Getting Ready for Testing

Today I finished the plumbing needed for testing and laid out initial electrical wiring. Here's today's progress with questions. First I attached the manometer bracket.



Then I addressed the water and steam tap hook-ups. Both connectors look like this. The photo isn't focused well enough to show a slight groove worn in the flat end that pushes up against the brass of the valve, which suggests the connection should be metal to metal. I don't recall removing a gasket for these pressure fittings. If they leak I'll make gaskets and seal the threads with plumbing tape.



Here they are tightened to the point of strong resistance but not overtightened. I learned earlier not to strip brass threads.



Finally I put the caps on these valves and turned them closed.



With the plumbing ready for testing (soon I'll reconnect the vacuum breaker and will connect the Sirai PSTAT), I turned to electrical. Here I fasten in a 20 amp waterproof On/Off toggle switch. On is up.





I tested the terminals of the heating element with a multimeter and it showed a steady 15 ohm resistance. That means the heating element is working. Then came a tedious project of trying to adapt the old 5/8 inch spade connectors to new wire. I obtained some spare wire by shortening a long power cord. Now I'm trying to reconcile U.S. and European standard color codes. My old photos show these may have been installed in confusing fashion. That's not a surprise considering a knot was used for strain relief. In the prior hook-up a white wire went from the Sopac PSTAT terminal 1 to the heating element tab on the right. I believe that's a hot lead, though, so the wire should be black in U.S. standard. (Check photos a couple pages back to review old color coding.) In the old coding a black wire was attached to Sopac PSTAT terminal C but there was a blue insulator on the end, suggesting that was neutral, but I believe it was actually hot. Thus the PSTAT would connect the hot lead or disconnect it. A blue wire went from the power cord to the terminal on the left. The yellow/green ground wire went to the frame, matching the green wire in my layout (it's not connected firmly yet). One of the old spade connectors broke when I tried to adapt it for my new wiring, so I'll hopefully pick up new spade connectors tomorrow. This should be interesting on Christmas eve.





Wiring I have yet to add include a thermofuse that I think should go in the hot lead between the PSTAT and the terminal to the right and the switch, where I'm not sure if the hot versus neutral poles matter because the circuit is either open or closed with the toggle. Otherwise should the hot lead go to the top (On) screw and the emerge from the bottom? Then the hot will go from the switch to the right terminal. I'll soon draw a wiring diagram (it's now in the next post) and will appreciate others feeding back whether I am on the right track. Of course this is entirely at my own risk. I'll fill the boiler with water before start-up, will have the power cord connected to a ground fault outlet and will wear rubber gloves and avoid water when I first turn it on.