cpu temp and PETG melting point

[n00b_monkey]

Hiya!

Just got my water cooling loop all set up.
Im doing some stress testing today.
Now I just read a post about a leak as a result of the temps being too high.

Running Intel burn test, My CPU temps hit a max of 65 degrees on some of the cores. Should I be worried?

My GPU is hitting a max of 46 degrees, on furmark.

Any thoughts?
Thanks for all the help

 

[andy_mk3]

No you should not worry about the cpu and gpu tempts, it's the coolant temperature you need to monitor. With a sustained load and not enough cooling, the coolant temp can gradually rise up and beyond the glass transition temp of PETG. The glass transition temperature is different to the melting point, glass transition is around 60-70c and is the point where the plastic becomes soft, which is exactly how you bend the PETG tubing with a heat gun. The melting point is usually up around 200c.

So when the coolant gets warm enough to hit that glass transition temperature, the pipes can bend and buckle under their own weight and cause leaks at the fittings. You want to measure the coolant temperature either with an in-line device with its own display, or a temperature probe that screws into a spare fitting that can be measured in software. Personally I'd keep coolant temps at a maximum of 50c to be safe. I think my system usually tops out around 35c.

 

[str]

Coolant temp for mine tops out around 45c but generally it's below 40c with air intake around 30c. It's configured to run silently most of the time:

 

[pastymuncher]

People have been scaremongering too much about PETG tubing on here. It is perfectly safe as long as you keep it within it's operating window which is exactly the same as any other component. I have been using it for a few years now and have had no problems at all. PETG tubing has a safe limit up to 60 degrees C, exceed that and you will have problems. My arguement would be that if your water temperature is that high then why are you bothering with water cooling anyway as it defeats the object of spending all that money because if your water temp is that high then you are going to have cpu and gpu temps inline with or exceeding high end air cooling temps. Ironically all this panic about PTEG tubing overlooks the fact that most other water cooling components also have a max rating of 60 degrees C while some, but not all soft tubing is safe up to 80 degrees C. When building a water cooling loop it is important to have a inline water temp sensor so that you can keep a eye on water temps and if it is getting too high increase the fan speeds. Setting fan speed by the water temp is a far better way of controlling the fans than using the cpu or gpu temp which will fluctuate wildly. Water temp on the other hand is much more stable and will prevent your fans by ramping up and down all the time.

You are reading cpu and gpu temps which will always be higher than your water temp so you are safe. If your gpu is only hitting 46 degrees then your water temp is probably in the low-mid 30's. If you have a spare port in your reservoir, distro plate or even a radiator then you can easily fit a temperature probe to keep a eye on your water temp. I have one in a spare port in the base of my reservoir and it has a LCD screen displaying the temp but you can get others that connect to a temperature header on the motherboard but not all boards have these. Some examples of different types of temperature sensors are here, here and here. The first is a temperature sensor that screws into a unused port anywhere in your loop while the wire goes to a header on your motherboard or fan controller. The second is basically the first one connected to a "T" piece which converts it to a inline sensor. This type requires extra fittings though as it goes where you would normally have a straight run of tubing or you fit it to a inlet/outlet by using a male to male adaptor and then fit the fitting that you would have put on the inlet/outlet to the other side of the "T" piece. The third one is a true inline fitting and would normally fit on a inlet/outlet anywhere in the loop. It doesn't really matter where you fit the temp sensor as there is very little varience in temps across the loop. I used to run a pair of inline temp sensors, one on the inlet to my pc and one on the outlet (my rads are external). I found that the difference in temp before the cpu and gpu and after only varied by 0.6-1.2 degrees C and it wasn't worth monitoring so on my next rebuild fitted my current sensor to a spare outlet on my reservoir. I manually set my fan speeds to keep my water temp below 24 degrees C which works out at a silent 780rpm for my fans and for most of the year don't have to adjust it, hot periods are the exception. Currently it is sitting at 15.4 degrees C (outside air being drawn through the rads).

If you want to control your fan speed by water temp than argueably the best way to do it is by using a Aquaero. It's a excellent bit of kit but it's not cheap. In fact if you get carried away you can disappear down a rabbit hole with the huge variety of sensors and other accessories for them and it becomes extremely expensive. This is the main reason I haven't bit the bullet on one because I know that I wouldn't stop at just water temp and fan speed. Even so, it remains probably the best bit of kit for automatically controlling cooling of our pc's.

 

[im4gine3]

ps.. technically the AC inline is not a true inline as its just a normal temp sensor with a removable cap fitted on top. The sensor 'tag' wraps around the outside of the fitting and a cap secures it in place. Even then not fully secure, as a slight tug the cable disconnects (i have one). Prefer all the others tbh... but all do the same thing regardless

 

[n00b_monkey]

Thanks for offering up so much information.
Everyone on here is so helpful.

I have learnt a fair bit that I will incorporate into my next build.

This hobby is definitely addictive and expensive!