This is confusing. The first post in the thread said you have the right size, 2 tons, but still a 410 TXV. That sounds like a GAF2. But above, you saying you have a TAM4, GAM5, TAM7 or TAM8 with an EEV and it is set for 22?
Obviously the lineset is outrageous but hard to argue with "it worked before". What kind of temp drop did you have on the liquid line when it is 67 indoors? What did it leave the condenser at? Did you check superheat? If it is a 410 TXV, beenthere says it would be flooding the coil so superheat would be zilch. If it is an EEV set for 22, you shouldn't be too far off on superheat unless low on gas or starved for gas.
375 feet is outrageous. would have walked from that job. Have work on units with 225 that lost compressors like crazy due to oil not returning fast enough to compressor. good luck. if you have the old air handler might look at fixing what ever was wrong with it and reinstalling it.
out of curiosity was the old unit fixed orifice? if so i would pull the piston in it and see what it was use it compared to what the unit would have come with to give you an idea of what adjustments may need to be made to the expansion valve.
And I knew the air handler was a long ways away from the condenser but really didn't think about how long it was and that it would have an effect on the system like that. I knew it had a liquid line solenoid at the A/H and a suction line accumulator at the condenser so I guess I figured all is well. Shame on me I know.
It was never 67 indoors that was the temp of the liquid line in the attic at the air handler.
When I arrived it had a 6 degrees of subcooling and I don't know without looking at a pt chart or my gauges right now how much super heat I had but I can tell you that the suction pressure was 70 and the suction line temp was 87 degrees.
I looked at the data plate of the condenser and it read 10 degrees of sub cooling so I started to add refrigerant and the head pressure did rise and the liquid line temp at the condenser fell. I stopped and started scratching my head and took a temp difference across the evap coil and it was 10 degrees. I decided to call a few other techs and was told "I dunno". I called tech support and that's when he basically laughed and was like "seriously how long is the line set?" And proceeded to explain why it won't work and to try to lower the fan speed. After I lowered the fan speed the suction line temp fell to 58 and the suction pressure of 85 and I had 14 degrees of subcooling. That's when the client arrived and I explained the problem and gave a solution. And quickly packed up and continued to run more calls as I was extremely way behind schedule and management was on my butt to get going.
when there is really long line set it normally is stepped down like a truck line on ductwork 7/8 to 5/8 to 1/2 to the air handler. you lose capacity the entire way. the liquid line solenoid sounds like a pump down system to me is it pumping down? what brings on the compressor, a pressure switch? is the accumulator aftermarket? i have seen accumulators installed with very long line sets. also assuming it is a pump down system with that long of a line set i am thinking that the expansion valve would not settle down and run at a constant number for a while after startup like 30 min just guessing with that.
Post some numbers. We can better understand what is happening and provide better advice with more info.
More info = More knowledge.
Suction Pressure? Head Pressure? SH? SC? CFM? Delta? Indoor wet bulb? Indoor dry bulb? Outdoor ambient?
Sorry. Didn't see that last post by Jupiter.