Have a cope 4d 15 ton I think but that’s neither here no there. Seldom intermittent oil trips. Oil consistantly runs foamy- all the time. There is plenty of oil pressure and superheat is plenty – 15-20 at the compressor. HGB takes care of low loads. There is an unloader but have done numerous tests and doesn’t seem to have an oil return problem from running part load. With compressor off oil in glass is about half/ little less then 3/4 full so I doubt there is oil over charge hitting the crank causing foaming- yes here we go again another thread about foaming. My question is IF a heater had gone out and had been replaced (by others not me) can the oil stay laced with liquid even with the heater up and running after plenty of time? I with compressor off I don’t see any foam or bubbling in glass.