ASI294MC Pro Cooling Issue

Please disregard my previous post as I discovered a setting that I had not selected. However, now that I have, the temperature still does not reach the specified temperature. I am attempting -15 degrees C in 19 degree ambient. Could this be a hardware issue?


Aprox time of issue: see log

Link to Logs

Useful Info

OS: Microsoft Windows 10 Pro
.NET: 4.8

If you look at the screen grab, it is only cooling at 37% - so it should be able to go cooler. If you fiddle around with temperatures while cameras are cooling, it is possible to confuse some. You are also trying to cool down to -15C in 1 minute. Not a good idea. Best practice is to cool and warm the camera over at least 10 minutes. Thermal shock is a good way of potentially killing a sensor and also causing condensation.

I actually tried ten minutes and unfortunately I get the same results. It does go below -15 for a couple of minutes and then retreats back at -14.8 and oscillates back and forth to -14.1

By the way, cooling behavior is exactly the same with NINA.

These cameras normally have two stacked Peltiers (each can do -20C) - it might be that one is not working.

Do you know if there is a way to diagnose the issue and be sure?

The thing that doesn’t quite make sense is the power. If it was 100% and not cool enough…

It still may be a firmware or software issue. Good idea to find someone else with same camera and compare notes.

I was hoping to find someone with similar experience here although I have now sent a message to ZWO support.


My ASI294MC Pro color camera gets down to -25C but only if i put it in the refrigerator which is theoretically at about 2 or 3 C ambient.The best I can get with either of my ZWO cameras is -25C temperature reduction. If I try for more, I run the risk of the camera not achieving the temp while I am shooting a sequence and the temperature going up while photographing. This is why I never try for more than -25C delta t any longer. I have an ASI183 OSC camera also and I was not ever able to get the 35C of temperature reduction stated in the specifications. I was interested to know if you set it to -20C, and that is not more than the 35C below ambient, does the power go up to 100%? I think that if you set it at -15C and it gets to -14.1C you should still be OK to use it. If you have reasonable ambient temperatures and set it to -20C and that is not more than the -35C it is rated t o achieve, and the power goes to 100% yet it does not go below -14.1C, then you have a hardware problem. There is no firmware update at this time for the ASI294 camera. The other thing I find interesting is that in your example you say that the ambient is 19C and you are setting the camera to -15C (which is -34C delta t) how can the camera only be at 37% power use and achieving -34.2C temperature reduction. Something is wrong with the data.

I am now at peace with my 294. The camera has a cooling limit of between 35 and 40 degrees below the “ambient”. And ambient is the ambient temperature of the sensor which could be warmer that the space which I myself am sitting in or the space the camera is sitting in. The fan tries to ward off the warming temperature of the sensor in order to keep the sensor’s surrounding temperature (ambient) low enough as the whole camera begins to warm up.

I am still test-imaging with it and can bring it down to -10c which seems to be what everyone else is doing and I am getting good results with it.

I am beginning to realize that a short delay between images may be useful in keeping the temperature from climbing. I notice that when I take biases - the temperature then can’t keep very steady no matter what it is set to.