i replaced a txv on a trane a/H ordered factory valve and installed. i pressurize system to 300 psig through my high side it kept droppping so i figured hmm i have a leak, isolate liquid and suction lines they both hold ok its in my evap coil.
so i put a gage port on the liquid line entering txv pressurize to 300psig and it drops im going crazy for this leak so i put a gage port on my suction sideof the evap coil, then i realize its pissing through the valve slow. i heat the bulb a little and pops open cool. but here is where it gets me. if i pressurize through the txv inlet side it will hold 300psig and only go up to 175 max on the out bound side, so i pressurize in reverse through suction now its the opposite. evap side holds 300 and txv inlet will max out at 175psig its something about the pressure differential across the valve that makes it close up it my only thought never seen one act that way???????? any body encounter that or know of it?