Hi all
called to a Airedale compact chiller (air cooled) KKCS9-K66/S model working as part of a close control system via a indoor AHU. The room temp had gone 2 deg above setpoint and was struggling to get it down. Indoor coil was warm so went to check chiller. Compressor was running but was encased in 3 inches of ice. Bottom of txv iced and all uninsulated sections after txv iced back to compressor. Stopped unit allowed to thaw. On restart suction 1.5 bar discharge 18 bar. Reftigerant R407C unit evaporating at -15 superheat high 33.8degC Subcooling low 4.5 DegC. Liquid line sight glass foaming then clear for a second and starts to foam again. Compressor oil level low also foaming. Compressor starts to freeze almost immediately following startup. Checked system charge 2.84Kg short. Notice oil seeping from access port at evaporator inlet engaged schrader and oil pissed out. Initially thought it was oil/ water mixture and that the evaporator had failed. Put system on pressure test left overnight pressure held at 21 bar. Customer tells me the unit has been maintained but refrigerant charge been untouched since first install. Since we don't have a leak I'm thinking faulty TXV and will replace that. Do people agree or should I be looking else where maybe blow through with OFN evacuate and recharge with correct factory charge first could a 1/3 reduction in refrigerant charge simply be the cause. Plus stupidly I didn't have a fiddle around with the txv prior to recovering the gas was late in the day and just wanted to get home so went with the obvious. What you think any advise gratefully received
