Welcome to SPCR!
Looking at pictures of the motherboard, i see it has as all motherboards the cpu socket (with the square and semi layout of the cpu mouting) clean, so i don't think you should have any issue mounting the HR22.
I want to give it a try for a fanless semifanless solution (until 55° are reached, from bios i want to set 0 rpm fans) with i5 4570!
Here i dont want to discourage you, but im going to address two important things.
1) PWM fans.
Not all PWM fans are created equal, some can drop more than others, and more importantly in you case, some PWM fans can drop to 0rpms, while others don't, it really depends on how the PWM of the fan was design. Im going to leave you a couple of examples where even at 0% it spins and other that the fan should stop if the %PWM is reached. So chose careful the fan you will use, and search if it can drop to 0rpms or not.
Also the motherboard PWM fan control might or not affect this, some have failsafe or restriction into going into 0rpms, or alarms, etc.
Another thing worth mentioning, is that going fanless certain portion might or not be good, depending on the fan you chose, like for example the NF-A15 PWM, i personally cant hear anything at 200rpms, and most of time, the very little air movement does impact a lot the temperatures, so lets say a 200rpm could help you not to reach 55C as easy, as with it being fully fanless for that portion, and still not netting any perceivable noise, this you have to test on your own when the PC is built.
2) CPU TEMP
Haswell run hot, specially hyperthreaded CPUs, i seen better temps on quads that don't have hyperthreading so your might be different than mine. I usually idle around 30C with the fan at minimum rpms, around 530rpms, but with very light load i can reach 50C, like browsing the internet, this is the reason i assign not increse the rpm below 50C, where it starts to gradually ramping up, if i set for example 40C, then the fan would have been ramp up and down a lot, after 50C i do need a middle load for it to go up, so it plays good like this on my setup. Now on a fanless startup, idk this is something you will have to test with your hardware, as i would think that you will pass that 50C much easier than me, my guess is you will be in the zone that i tried to avoid, but then again my CPU is hyperthreaded and runs much hotter than an i5, so you might not have the issue, this is why i say its more important to test it once you have it up and running, as there is no way of predicting it.
Now one thing that you do have realize is that the fan that has the biggest impact on the CPU temp is the CPU fan, so this was the main reason i left mine unrestricted, my case fans can only reach 37.5% PWM, which tends to be 650rpms, while the TY150 on the HR22 was left unrestricted so it can reach the rated 1100rpm if its needed, but no game will take it there, only benchs like prime95 can, again this will all depend on all your setup, and this has to be setup like you want to, but until you build it.
What i would do is also play with the case fans, when i set up mine, i ran probably more than 40 times prime95 with different fan settings, restricting CPU, restricting case fans, both on minimum and maximum rpms, etc to feel the noise the setup could reach and temps. In my experience (this might vary on yours), the case fans dont have a huge of an impact as the cpu fan, also the cpu fan could spin higher and i wouldn't hear it as easily as the case fans, so for my setup, it worked out better to have higher rpms on the CPU FAN and lower on the case fans. Again all of this is very dependant on each setup, so test it once you build it.
If you don't understand anything i posted let me know, ill try to detail it more.