New Barrow Slim CPU Pump Combo
Updated: May 13, 2022

Barrow has made this CPU Pump Combo block for over a year now and it's time to refresh. The block in the above picture is the new model LTPRPA-04 S which is very similar to the original model LTPRKA-04

But if you look from this side, the inlet/outlet portion of the block is much slimmer.

The original model has thickness of 45mm in this part. But the slim version measure only 23mm.
That's 22mm thinner!
You'll have to remove the pump from the block to twist in angle fitting. There's a white O-Ring for pump gasket and the pump construction is the same as other LIANG DDC pump. When pull out the propeller, there is a white ceramic ball inside to function as roller bearing when lubricated by flowing water. When large air bubble trap inside or no water present, this bearing it will grind and wear out quickly. This is totally different mechanic found in AIO pump, the air bubble can not kill the pump but it will make bubble noise.

When I dropped in some water, the most right port is connect to the middle port and the inlet opening of the propeller. The most right port would be the highest point of the pump when installed, and any air bubble that flow through the inlet port will float up and detain in this portion. Barrow calls this air trap portion "Reservoir" which is not entirely accurate. Because this reservoir is so tiny, a small shake and vibration would induce the air bubble to be sucked back into the propeller again. The original version obviously has bigger reservoirs than this new one. I doubt how well it will perform.

At the top of the pump there is a controller board, no thermal pad present. But if you need to put one in, it should be 1mm or less. The pump housing and cover are made from aluminum. The connector port is proprietary to Barrow which is different from Liang DDC that has wires (Colorful) directly route from the pump.
First picture is Barrow proprietary connector. The cable split into 3 parts, the speed control knob which can be used to turn on PWM control mode when turned CCW, second is PWM header and the last one is 12V Molex.
This pump is actually not louder than 17W Liang DDC that I have when put under normal size reservoir. I usually set the speed to 2800 RPM for quietest noise level.
There's no manual found in the box. They made such a good product but they can't afford to make an install instruction. This one comes with new Intel bracket. There're notches to adjust the hole distant and one of the notch says "LGA1700"
AM4 bracket is sold seperately and can be swap out by removing the cold plate.
In the package also includes small pack of thermal paste and 2 Allen keys. You can use 2.5mm Allen key for removing the pump screw. The pump housing is made from POM material. So be gentle when tighten the pump screws. The thread can be ripped off easily when overtighten.

Here's the best part of this pump combo - It's short.
As you can see from the picture above. The tallest part of the block is now the pump cover. Before this, the tallest part would be the angle fitting and it makes this block as tall as 85mm when used with regular angle fitting. (Most angle fitting is 27-28mm tall)
Now this block is only 65mm tall, it's even shorter than Swiftech Apogee with 74mm in height.
This is direct competition with AIO cooler. It has better cooling performance with all copper and higher flow rate, the radiator can be swap out as need when changing the PC case, the tube can be cut to specific length, it can be taken apart for cleaning, and the replacement pump is not so expensive.
The bad part of this pump combo is its tiny reservoir. Filling the loop need a separate reservoir (60x150mm to be minimum) You will need to flip the case around and turn the pump on and off many times to remove the air bubble. It took me over 2 hours just to repel the air bubble and there's always some stuck in there. When moving the PC case the vibration will cause the air to go right into the propeller and generate unpleasant noise. Sometime it's even grind the ball bearing if it's a big bubble.
So, I have the idea of putting small 50x60mm reservoir over the fill port. But it will take up some space, maybe I need to lay it horizontally or make a PC case that this reservoir can be place into.
The space between ports are very tight. In the picture I put in 16/10 compression fitting from Barrow. It almost crash with each other. This one is 20mm diameter, so anything larger than this won't fit.
I'll do loop filling and sound testing in the next part. - Cheers.