The power pack will continue to work.
But in the absence of active cooling, it can overheat. As a result of either failure or fire.
Do you have a low power system, so a large load on the unit will not, however, the problem is that it was designed under the active cooling, so it is possible and overheating at low load.
Here is an example of a
compact power supply with passive cooling.
There are two possible options -
1) buy a dedicated PSU designed for passive cooling.
2) Make a fan control depending on temperature. Ie, that he was always off, but in the case of temperature rise were included.
P. S. But not too powerful power supply you chose for your load?
Judging by the description of the configuration you have the maximum peak consumption is not more 100vatt.
And the power supply on 600ватт.