Originally Posted by feltonmichael
There is no charge issue with varying water temp, Everyone over complicates things I've been using a system just as you described for years no problems. Do it and save your self tons of money
Well it is a little more complex than just swapping the coil, vacuuming and charging
. With just about all window ac units having a capillary tube they are charge critical. Too much refrigerant and you get liquid back to compressor
and too little causes high super heat which means lack of performance, high discharge temp and shortened compressor
With reefer box it's easy to look for a frost line to guess on charge but not on a ac unit because coil runs above freezing. So you can charge on cool day and be short a charge on a hot day. There are plenty of marine ac units that use cap tubes so not saying it won't work just that getting the charge right is going to take a lot of patience and monitoring superheat with a good type k or similar thermocouple.
Or go down and buy a chatlef style flow-rator style housing and use it with a small TXV. Then your charge problems are gone and will work at maximum efficiency in all conditions. That's what I would do and would only add $30-50 to cost.