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-   -   TXV compressor with orifice tube/piston coil (http://www.diychatroom.com/f17/txv-compressor-orifice-tube-piston-coil-145363/)

aselby 05-30-2012 12:43 PM

TXV compressor with orifice tube/piston coil
 
I'm an ASE certified mechanic with my 609 certification but I'm not up to speed with residential HVAC systems. I recently bought a foreclosed house and the previous owners removed the outside unit (compressor condenser fan) from the a/c system. The air handler line set and ducting are still all intact. The air handler is a Goodman ARFU 030-00a, it is a 30k btu coil with an orifice tube. I acquired a 6 year old R22 Lennox HS26-030 outside unit from a friend who had an addition put on his house and upgraded his HVAC system.
here are my questions:
The HS26 says it is designed for use with an expansion valve, can I use it with an orifice tube coil?
The HS26 was removed by "a professional" the lines were cut and the valves inside the unit were shut off, will the system need to have any oil added or is it all contained in the compressor?
The line set on my Goodman unit were cut and might be a little short to fit to the HS26, do they make couplers to extend the line set or will I need to but a new line set? The lines are the same size for the Goodman and the HS26.
I do understand that the orifice will not be as efficient as a TXV but I'm on a tight budget and need to know if it will work. The air handler is in my attic and doesn't have a ton of room to get it out.

Doc Holliday 05-30-2012 02:56 PM

It will work but you need to know what the old condenser was or at the very least what size piston is in the evaporator right now.

You will not know anything about system charge until it's hooked up and opened. Whomever very well may have pumped down the refrigerant into the compressor of this Lennox you now have. You can VERY SLIGHTLY unseat one of the service valves to see if anything comes out but very quickly close it off.

That's about as far as you can go until it's opened up into the lines. Copper refrigerant lines can easily be extended to reach wherever they have to, just braze some length onto what's there. You'll need to remove the shraeder valves before brazing condenser in to avoid melting the seals. Re-install the valve cores after a few minutes, once the metal has cooled off a bit, pull a vacuum down to 500 microns AFTER nitrogen pressure testing and cleaning and finally let any possible remaining refrigerant into the lines. Your gauges will let you know how much you have.

beenthere 05-30-2012 03:30 PM

Jut get a TXV for the indoor coil. it was made that the orifice can be removed, and a TV installed instead.

aselby 05-31-2012 12:47 PM

Thanks for the reply, i got a TXV and will braze it in, my second question is do i need to add any oil to the system? if so how much and what type? Thanks, Andrew

carmon 05-31-2012 12:52 PM

i would not add oil....

raylo32 05-31-2012 02:19 PM

You also might check with the tech that removed the HS26 to see if he pumped it down keeping the refrigerant charge in the condenser coil. If so, you might not need much new refrigerant after you evac and open the service valves. Still should certainly check the subcooling and adjust charge if necessary.


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