working on a split system. Lennox S- series 5 ton outdoor condenser. CBX27UH air handler
410a. Diagnosed last week as a bad TXV as the suction pressure was dropping constantly as the head pressure stayed constant.
Adding refrigerant did nothing. There is a high heat load in the space - 90 deg F return temp.
The air handler is about 15 - 20 feet below the condensing unit which is on the roof. There is a p-trap installed on the suction line
We replaced the TXV today. No change. I told the tech to remove the bulb and put it outside the unit. The suction stabilizes however, it is too low at 115 psi.
Head Pressure is 250 psi (which is also low). One thing that the tech noticed, is that after we had pressure tested, and vacuumed the lines and then were ready to release our charge into the lineset and evap - he opened the suction side valve and no refrigerant came out. This is a scroll compressor. Is this normal?

Regards,

JBW