Expobar Brewtus IV - No power to brew boiler when steam switched off & it keeps restarting when both are switched on.

#1: Post by **Sackman** » September 25th, 2021, 1:53 am

Hello all.

The problems below occured after the machine shorted and melted the toggle switch for the steam boiler.

1. The machine keeps restarting, but only when both boilers are switched on.
2. The brew boiler will not heat when the steam is switched off, even though there is power coming out of the relay.

The relay is good. I just replaced it, unnecessarily
Both boilers are showing around 13 ohms.
Safety thermostats have continuity and are not popped
Pressurestat is ok
PID starts with 1.05 and shows accurate temp.

I frequently read this site, but this is my first time posting. Any help from fellow home-baristas is really appreciated.

#2: Post by **ira** » September 25th, 2021, 2:14 am

When you say replaced relay, I assume you mean an SSR. If you measure across the output of the relay, you should see 117 when the relay is off and pretty much zero when the relay is on. Or across the heater, zero when off and 117 when on. Is that what you see?

Ira

#3: Post by **cafeIKE** » September 25th, 2021, 11:58 am

Have a look at Modding the Expobar Brewtus for faster warmup. It has a wiring diagram which might help.

September 25th, 2021, 1:28 pm

The diagram I had was not labeled. This helps. Thanks.

The old steam switch had three terminals and, although it was to melted to test, I presumed it was a spst that just had two load terminals. I replaced it with a two-terminal spst toggle and just attached both load wires to the same terminal.

Do you think this is right?

#5: Post by **cafeIKE** » September 25th, 2021, 2:22 pm

It looks like the steam switch is double throw

September 25th, 2021, 6:27 pm

Yes it is the SSR.

These two scenarios are likely relevant.

1. When only the brew boiler is switched on: SSR input has power from PID & SSR output has NO power from either terminal.

2. When the brew and steam boiler are switched on: SSR input has power from PID & SSR output has power from both terminals.

Also, and not sure if it matters, both terminals on the SSR's output show contiunity with the chasis when the machine is plugged in but switched of.

September 25th, 2021, 6:37 pm

Revised post

For the steam switch, It only has an on and off position, so I think it is a SP that just has 1 input and 2 outputs. I could not test the old one because it melted though. I had a SPST laying around and just put both output wires on the same terminal. Seems to work.

The power (brew boiler) switch, which works fine is a SPDT. It has two input and two output terminals.

#8: Post by **ira** » September 25th, 2021, 7:32 pm

The way the earlier Brewtus worked was the pressurestat was set up as a spdt switch. The off position gave power to the steam boiler and the on position gave power to the brew boiler. I believe the way the brew only switch works is taking the power from the steam boiler and moving it to the brew boiler so the brew boiler works like normal and the steam boiler never gets hot. And I believe it requires a SPDT switch.

Ira

September 25th, 2021, 9:31 pm

Aha! Thanks Ira. I will get switch. To be continued.

September 28th, 2021, 3:15 pm

You nailed it. I will toast you with my next shot Thx.