I got a call: a walk in cooler not cooling.it is a 2 hp water cool condensing unit with a liquid receiver and 2 tons indoor coil,the tev is danfoss tx2 model and the orifice is #4, R22 system.
The coil was build up with ice when I got there.After the ice melt and start the unit. The hi side pressure is 170 psi and low side pressure is 28psi. The outlet water temp is 75f and inlet temp is 47f. Adjust the water regulater and set the outlet temp to 90f. The pressure go to 200 psi and 30 psi, the super heat is 50f and the sc is 16f. Ice start to form again. Checked fans and comp,volt is 116v and 230v, 0.5 amps for each fan and 4.6 amps for comp.Check filter drier,side glass,no restriction.replaced the orifice for the tev. It had the same problem. Top up with 9 oz r22, the suction pressure up to 33psi and liquid line pressure is 225psi. The super heat is 48f and the sc is 46f. And the liquid line became cold. Hold the bulb of the tev, the suction pressure went up to 36 psi, Is the tev not good and why the sub cooling went up and liquid line became cold? Thanks .