Hi Jero20, welcome to AQ!
Wow, you bought a 2nd hand Resun C0500 which had been used for 5 years! Usually, for a 2nd hand Resun chiller, it is advisable to buy if it is not more than 2 years or so. But in your case, it is advisable to send your unit for maintenance repair or top up of liquid refrigerant as 5 years is already too long. Ask the maintenance person to clean the chiller too. A difference of 10 degrees already indicate that it's cooling capacity is not as it should be. So I guess it's time to send your unit for maintenance. Also, there is a sticky thread on top of this section with a manual for a Resun CL650. Should be similar.
Hope this helps.
Bookmarks