Ive got a desert aire pd0500. Going off memory. 500 is right. 2006 model. A txv was put in last year. I replaced the txv under warr. Would work fine in dehum go into cool and would shut off on high pressure. Blew out system good deep vac.3 months later unit shutting off on low pressure in both cooling and dehum. Replaced all driers blew out system. Found metal at txv. Looked like sight glass came apart. Replaced it and liquid line solenoid valve with driers. Added one on discharge line and before solenoid valve. Has a factory one on discharge line. Used suction driers for future diagnostics. Anyway i caught it cycling on low press switcch again. No drop across filters. Running great now for 3 days. Only thing i didnt change was solenoid coil. Last time it went down low side was near zero. Put it into cooling and it hasnt acted up in either function since. Something is up short of replacing everthing again without being sure im at a loss. I know its txv or soldnoid. What else could give me an intermittent problem like that? 49' lineset added 26 additional lbs r22. Usually do t see 0 on the gauge. Switch opens at35 closes at 55 or 60. Thinking about removing solenoid as a way of eliminating a possible problem. Readd later. Anyone see a problem with this. Unit rarely shuts off. Txv bulb just like my wife clean tight and on top. Itis a 7/8 line. Scratchin my head thought i had it whipped ( twice). Just started my own biz and this one is kIckin me. Havin to give too much already on this one. Thats why Im proposIng temporarily removing solenoid. Ive always had good luck with these units so im open to advice. Prolly loOkIn me right in the face. Hate intermittent problems. When running outside temp 78 88 inside 55% humidity. Hi 245 lo72. Will bring it back into perameters in no time when out of whack.