A snapshot or two from multiple angle of the SSR, steam boiler control switch, steam heating element connections and Gicar control box would help.

The SSR can either supply power to the heater or connect the heater to neutral. Since you have 240V on one terminal, it's likely supplying power to a grounded heater. So either the control line is not working or the SSR is blown.

The side of the SSR that does not have 240v on it should have 5-12VDC between the pins if the heater is on.

Jeff wrote:I believe a lot of this has to do with them being poorly heat sinked

Bingo. Heat kills solid state. This SSR is old enough to vote in some countries.

Of course I will try to attach them.

Thank you for this find. They have a UK branch which is good.

Just before I pull the trigger on this, when I open the steam wand knob or the hot water one should there be cold water running out or does water run only when the steam boiler is hot and under pressure. I get nothing at the moment. I just wondered.

No steam, no hot or cold water as the water is forced out by steam pressure.

Were it my machine, I'd add a heat sink on the outside of the machine. Also NEVER start both boilers from cold. Heat the brew boiler then the steam boiler. On my DB, I only heat the steam boiler when making the missus or guests latte or Americano.

This snip from Amazon for a QM75 seems to show dual SSR w a tinkertoy heat sink on each. Dual units would be a good idea if you have the room. Not sure what the UK heater ratings are, but you could likely use a smaller unit for brew boiler and a heavier one for the steam.



Current unit says PID control of steam boiler. Do you have control signals on both SSR sections?

What you are saying makes a lot of sense. It did cross my mind about separate SSR. Beside it is only the steam boiler side that has failed so I could just get one for that however I wouldn't be confident on what the parameters should be to choose the right one. Definitely going to add a heat sink though.
The QM67 doesn't allow you to start the steam boiler on its own but you can have the brewing one on its own.
There is control signal going on both of them as the two small Led lights on SSR body are on. The brewing side goes off after boiler has reached temperature and the steam one stays on. Both sides are controlled by the PID. I understand that when an SSR fails it always fails when on the on position.

I am going to go ahead and order the SSR and see.

One positive thing out of this is that I have definitely gained better understanding of how the machine works which is fascinating. They really are a chemistry set. I also appreciate the guidance and help I have received here.

I understand that when an SSR fails it always fails when on the on position.

As Jeff said, SSR fail in multiple ways. Yours has likely blown the output control in the 'open' mode. Which is better than 'closed' as then the boiler would continue to heat until either the over temp or over pressure controls opened.

You can likely get two SSR for less than the dual. You'd need the similar style with the output status to light the red panel leds ... or bodge it up with a diode and a resistor enabling use of more generic and less costly SSR. Let me know and I can help with circuit and part suggestions.

In thinking about the SSR mounting, if you can mount on edge with a couple of L-brackets and attach a finned heat sink so the fins run vertically, it would help considerably. Again let me know and I can help with part selection.

Bonne chance!

Thank you for the offer to help I have already ordered an identical part from the website suggested above.

On reflection it did blow on the closed position and it let steam out so the over pressure controls must have opened.

Just looking at an appropriate heat sink. I was thinking about putting in under the machine on the outter body. I only have 20mm height there provided by the legs. There is not a lot of room inside due to the shape of the back panel which houses the water tank. It bends inwardly in an L shape over the SSR so I won't be able to elavate it. I would appreciate help with getting the sizes right. How large does this need to be?