Thermochill PA120.3 15mm

Thermochill Logo


If you’re unfamiliar with the Thermochill PA120.3, you’re either new to watercooling or oblivious to the world around you. The PA series from ThermoChill has been the standard and what all other radiators are judged by. It has been roughly 5 years since the PA was released and remained unchanged even through all the griping about the crazy fan spacing and goofy G3/8 barb ports. Personally, I don’t have any issues with the G3/8 since you can snatch some BP G3/8 barbs or adapters from one of the many manufacturers. However, that wasn’t always the case…there was the time when PTFE tape made G1/4 fittings seal in G3/8 ports. Even after all the griping in regards to fan spacing, dimensions and barb ports the PA series remained true to the original design. Back to today, ThermoChill has new owners and finally some new products including the updated PA series. On the bench today is the PA120.3 with 15mm fan spacing versus the former 24.5mm.

Radiator Features

The only major change to the PA120 series is the change to 15mm fan spacing, oh and say goodbye to the puzzling bleed screw (show of hands on how many of you actually used the bleed screw feature) on the end tank. Change the fan spacing from 24.5mm to 15mm, so you really lose 2cm of core. The real question is whether that reduction in radiator core has any meaningful impact to performance, which we will certainly be looking at.

The PA120.3 15mm as I call it now measures in at 405 x 129 x 60mm (LxWxH), just a 20mm less in length. The 10mm plenum from the core to the fans remains as does the performance optimized 10FPI. Even the confusing self-tapping 6-32 screws, I’ve never used the included screws, they scare me with the self-taping (aka: tube piercing) point on the end. Plus, they aren’t long enough for 25mm fans, so what are they really included for. I just use standard 1.25in. 6-32 machine screws for 25mm fans and 5/8in. 6-32 machine screws for open corner 38mm fans. Now for my usual fan mounting public service announcement… Word of caution for anytime to mount fans to a radiator, always check screw depth through the tapped holes… puncturing a tube is not a fun adventure. Put the screw in the fan hole and set the fan on the lip of the radiator, if you’re close then you need slightly shorter screws.

Another thing I see different, or didn’t see is the neoprene gasket. I cannot say that I was sad to see them go, while the gasket does help seal the fans and plenum it was just a royal pain to get the gasket and fans in place. Not to mention making sure the gasket wasn’t obstructing the fan blades from spinning. The PA still sports the matte black paint job. So some minor differences, but the only major difference is the 15mm fan spacing… oh yeah, the PA’s now come in a white box with foam wrap versus bubble wrap.

  • Matte Black Finish
  • Copper fins, brass tubes and end tanks
  • Dual row, Two-pass u-flow configuration
  • 10mm fan plenum on both sides
  • G3/8 Barb ports
  • 10 Fins Per Inch (FPI)
  • Standard 15mm Fan spacing
  • 6-32 untapped fan/mount holes
  • Dimensions: 405x129x60mm (LxWxH)

The photo above is one of the standard shots I always take, just letting the radiator get the whole runway for a second. And below, we take a close-up and verify the FPI, and as advertised 10FPI is what I see and what the PA has always boasted.

As you scrolled here, you got to see the standard 15mm spacing. Sorry for the often dusty and tough to focus FPI and fan spacing photos, they are difficult shots for me to take with the current light tent setup I have. Don’t worry, I’m working on a better light tent though. I’m glad to see ThermoChill change over to 15mm spacing, but I own a case specifically made for the 24.5mm spacing. Luckily my case is already full with 3 24.5mm PA120.3’s. For all of you out there with cases specifically made for the old spacing, it will be difficult to find a replacement. I do have one minor gripe about the 15mm spacing in general, its just too tight when mounting fans. You need to be very methodical in order to get all of the screws lined up just right. I’ve adopted the mount the two outside fans loose, slide the center in place then tighten the center fan down first then finish the two outside fans. That’s the only method I’ve found that works well every time.

On to pressure drop testing…

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