Loss of refrigerant means there is a leak. A responsible HVAC company would find the leak before you spend any more money on refrigerant.

Your return may be undersized, but drawing air for the attic is a terrible solution. The seems to be clueless as to what is going on. You need to speak to the owner of this company, or find someone else to work on your AC.

If you want some additional information on HVAC then Reddit has an HVAC tech forum. There also is an HVAC contractor message board site where you can ask questions on their AOP Residential HVAC forum.

Magic 8 ball says: good chance the metering device has failed.

This is very common when it's discovered that the system appears to be low on Freon only to realize the system will not take anymore.

If this is the case it's a toss up as to whether or not to change the expansion valve or just replace the whole coil. Lennox just settled a lawsuit about defective coils.

These valves fail for a variety of reasons. If the coil is starved for air, that certainly will not help the situation, but it would be pointless to put a return in only to suck attic air.

Was this tech from a home warranty service company?

While it's not hard to change this valve, if you hire the inexperienced it's just as easy to damage the new valve during installation. So you have your work cut out for you.

A system that appears to be low on refrigerant, doesn't mean it is. Many things mimic others. This is why you need a pro to diagnose problems.

Technician roulette wheel is a gamble these days.

magic 8- many thanks ... i have been using this company since i built the house 12+yrs ago- the orig unit went south after about 6yrs, and they replaced it with this lennox unit. its a large company, which had an entire clean-out last year... they fired everyone from the general mgr to the secretary's .. the fellow they sent is the chief mech, with 30+yrs of experience, and he wants to pull add air from a hot/hot attic... jesus.. i am in a pickle...

When 6 year old equipment fails so badly it has to be replaced then bad installation is a likely cause. Now on the second system they have already replaced the TXV valve and its having problems. Again this sounds like more installation problems.

Now the most experienced tech wants to draw air from the attic to solve the inadequate return which this company originally designed 12 years ago. There is a reason why most of the workers were fired.

I think it is time to cut your losses and find someone who you can trust. If a parts warranty is still in effect then may you should look for another Lennox dealer.

thanks for the comments- the orig install when we built the house , the builder cheaped out most def... the replacement also done poorly (very poorly)- I do have a excellent a/c guy... BUT... my summer home is 90miles away, and he will do the job (and rite)... but I gotta wait till the off season in sept/oct... I'm hoping the system lasts thru the summer- if it should fail, I will not use the present guys- i'll go to walmarts and buy 4-5-6 window units to get me into the fall... spending 5/600 bucks on window units, is a lot better then spending 8500 (cost of last install) for a lousy job...

i built the house 12+yrs ago- the orig unit went south after about 6yrs, and they replaced it with this lennox unit. its a large company, which had an entire clean-out last year... they fired everyone from the general mgr to the secretary's.

Hmm, sounds like an investor infused buyout. The reasons for firings is not often what you think. There have been a number of these in my area and what happens in a 'family run business of more than one family member'... the member that has better money management buys out the other family members to take over the company themselves.

Then once the family member who bought everyone out realizes the ship is starting to go under, (the other family members did more than what was initially thought before buying them out.) The member that bought out the company decides 'I'll take out loans thru an investor' to keep the ship afloat. Or maybe they just decide it's not worth saving and sell out to an investor in one fell swoop.

Whichever way it happens, the investor is a bean counter. They likely have no mechanical knowledge, no real life experience or mental aptitude to be able to 'fix' problems.

So the investor being the bean counter they are... goes in and fires everyone. They think there is this pool of cheap talent that knows what they are doing. I've seen this happen more than once in my general area... I only know about it because I talk to people who have worked for some of these outfits. In what seems like another life now, I worked for a few of them.

i don't think that's the case here- the local long island company is owned by a large new England co, and the local co was being run so poorly, they fired everyone, and brought in all new people from the secretary on up... the head tech came by n checked my unit the other day and said he 'thinks' the unit is not getting enough return air flow, so he wants to cut a hole in the sheet metal return box in the attic and feed it with more air which he will get thru a vent he will cut in one of the rooms with 'conditioned air'... ofcourse my 1st question was didn't u check for air flow when u installed the system... his answer was the old no longer employees did the job- the other poss is that its a bad tx valve... in the meantime the unit has stopped working fully- when my wife turns it on, the outside compressor fan does not spin... I have another tech from a diff co coming by this afternoon... I'm sure it wont be good news...

marc... thanks.... in '2' weeks i having the '4' a/c's serviced for the summer... hoping all is well with em... had them do the 'spring' tuneup last 'aug' (yes they were a few months late), n that tech said all the readings were good... fingers are crossed they are still in good order