Several weeks ago I followed the failed maintenance supers's(several guys) attempts to fix a no cool. I found contaminated R-22 and a TXV installed with the piston still installed. The bulb was also not secured to the piping, nor was it touching anything, just sitting in the air stream. I removed the TXV, pulled a good vacuum and charged the system with new R-22, problem fixed.
Returned to the same property last week, different apartment. This system showed low on Freon, I don't remember the exact numbers but the SH was high and the Subcool was low. It also had a TXV, also not secured to anything just floating around the air stream. I didn't pump down and check for a piston. The pressures did change however when I held the bulb in my hand. I added Freon and left the Subcool at 10. They haven't called back saying it isn't working, but it's created a question in my mind.
These are old Suntherm units, Heat pump. A coil, the bulb jammed between the cover panel and the U bends at the edge of the coil, so not really out in the middle of the air stream.
The question is; Does a TXV bulb always have to be in contact with the piping? What will happen if it isn't? I did notice that when I added R-22, High side would shoot up very quickly, then slowly fall and stabilize.
The bulb must be attached to the outlet of evaporator and insulated. It response to the amount of super .most are installed at the 10 or 2 o'clock position
Service valves where u hook up gauges are 3 or9 if u look at them.If these ports were located on top would the boiling are saturation temp be the same on gauges or would it make that much difference
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Originally Posted by hewitt
