Originally Posted by Cromwell
Oh, ok. The heating element is a 5500W 240V ULWD. It does have a heat sink, but I didn't have a fan on it. I think perhaps it is getting too hot. Is it better to fan the heat sink, or to mount the heat sink on a bigger metal plate?
And will that SSR drive that element?
Yes this SSR will drive that element.
Problem is 30 Amps through a SSR creates about 30 watts of heat, that's about the same amount of heat generated by a old style 40 watt light bulb and all of that heat has to go somewhere.
Did you use thermal compound between the SSR and the heat sink? If not then this could be why the original failed - you can pick some up at any computer shop - just ask for heat sink thermal grease.
Not seeing your heatsink or how it's mounted we can't tell if it needs a fan or not. With the original SSR, did the heat sink get hot? If so then you need a fan. Warm to touch is OK without a fan assuming you used thermal compound with the original SSR. But fans are cheap compared to brewery down time & replacement SSRs.