What does PCB mean regarding miner temperature?

Hey, I’m just starting out in mining. What does PCB mean in this context? Like, in this table about miner temperature ranges?

PCB means Printed Circuit Board. They're referring to the highest temp the PCB can safely handle.

Yeah, it’s about the temp of the PCB or hashboard. The ASIC chip has its own heat sensor. If you look at the link, you'll see the PCB temp listed in the miner status. There’s a sample image showing the temp sensors under the heat sink.

Got it! But what’s a safe ambient temp for miners? In summer it can hit over 90°F. How do I stop them from overheating? Planning to run some Antminer S19 Pro units in Houston. The weather's fine now, but summer's brutal. Should I just get an AC?

Just keep an eye on your miners and try to stay below that max PCB temp from the link you shared. The S19 Pro can handle up to 80°C, any more and parts might melt. If you want AC to cool them, it's costly, but it's not strictly necessary. Set up good airflow with intake and exhaust fans instead.

80°C is really high, right? So if I manage air circulation, it’s cool even when the temp hits 100°F, yeah?

For sure, that's the spec for the older S9s. The newer S19s have a max ambient temp of 35°C. In the summer, you need to move air effectively. Aim for 200-250 CFM for S9s and 400-500 CFM for newer models. You need fresh outside air going in and hot air out without mixing. I’ve seen plenty of S9s running in 40°C without issues.