Re: Charging Heatcraft Condensing Units
Heatcraft's I & O manuals for their condensing units leave a lot to be desired regarding how to properly charge a system. In addition, their units' data tags don't indicate anything about either receiver capacity or winter charge requirement with a condenser flooding control like some other manufacturers do.
Just as I had to do some digging to find that PDF on the HyperCore flooding charge info, it took a bit of searching all of their published literature to find any mention of winter charging methods.
Here's a little ditty from a FAQ page which actually discusses it...in part (Scroll down to near the bottom under "Disadvantages":
FAQs - Flooded Condenser Using Headmaster
It states that after the sightglass is cleared add 15% of the initial weighed-in charge for operation down to 0ºF or an additional 30% for -20ºF.
Bear in mind that these guidelines were written before the advent of the microchannel designs and their vastly reduced coil volumes.
A more correct method for HyperCore units would be to clear the SG (while maintaining a condensing temperature above 105ºF by blocking airflow as necessary) and add the 2-3 lbs flooding charge as indicated in my previous link.