I got tired of waiting for Clive Coffee to send me the SSR for my Pro 500 so I drove the one hour trip there. It took me another hour to drive back. Anyway I replaced it and it worked. It was an easy job. I ran two double shots through it and the second was better than the first. I was reminded how good this machine makes espresso.
I relocated the SSR toward the back of the machine in a cooler place, basically as far as the wires would go. I'll see how long this works.

Did you find some metal to attach to? If not and it fails again, you can buy individual heat-sinks for most of those types of components. You'll also need some 'heat-sink' compound to smear between the heat sink and the component.. Put on a little as possible. Less is more.

I attached it to the floor of the metal "chassis" of the machine near the rear right corner. I noticed there wasn't any thermal paste on the bracket where the SSR was originally attached.

Assuming the package type of the SSR is metal and designed to have an optional heat sink, thermal paste is just orders of magnitude better than none, with the right (thin) amount.. you look under a microscope and you'll see the flat metal has 'bumps'. so the attachment is really only making contact at the bumps.. But I didn't look at my repair to see if they used thermal paste.. and its held up for 1.5 years after being relocated.

Just one last post for completeness in this repair issue. It is not uncommon for the SSR in the Pro500PID to stop working.. I see a few posts here in HB and also on Clive's site. On Clive's site, it looks like Clive's solution is to use a larger SSR which won't get as hot, when passing the same current. I think the major problem is the placement of the SSR. The yellow circle in the pic below shows where I think it was originally placed. Close to the steam boiler which creates a hot ambient around the SSR. I sent back the machine, but told the tech to relocate it in a better spot. The tech at IDC (canada) put it as shown in the blue circle..It looks like this is the location used by DJ (Bleach) above. I am unsure if my new relay is rated for more current than the original but it is away from the boiler in a much better spot *AND* is using the entire bottom case as the heat sink. It has worked well for about 1.7 years.

If this fails in yours, I recommend repositioning it, it possible.. (if you don't have to fabricate new leads).. otherwise you can see if you can get a higher capacity relay with the same footprint. Profitec will definitely know this is an issue.