Its cold here in Virginia....as with most of the east coast. I have been wondering for a while if my geo split system is working properly, and lately the performance has really dropped. Wondering if anyone has any ideas or input. Temp has been dropping near 0 in the evenings, and strip heater is cutting on a lot; temp set to 68. House is new construction, tight construction; 2 story on full basement. 3 ton 2 stage Bosch Package unit located in basement serves basement and first floor (1500 sq ft basement 1900 sq ft 1st floor). 3 ton 2 stage Bosch Split unit serves 2nd floor (1700 sq ft). Air handler and 2nd floor ducting is located in the attic (approx 34' vertical rise in lineset). I run open loop well water 60 degree incoming 6 gpm per unit parallel plumbing. The package unit does great, the compressor rarely runs up to full speed and the unit is periodically cycling on and off....getting 6-8 degree water temp change, 20 degree air change at the vent. The split unit is doing 2 degrees water change; 5 degree air change at the vent, and has been running for about a week now. Everything is 3 years old, I thought about flushing the water lines but both units run the same water so I doubt scale is the problem. I have always wondered about the split unit line set being sized and setup correctly. The lineset has always been a little noisy going up the walls; and I have read in some places that special consideration should be taken for big vertical runs to keep oil and vapors and refrigerant behaving properly. Does ambient significantly effect the performance of a split unit air handler? The lineset runs in an exterior wall so if that means anything. It only makes sense that the ductwork in a cold attic will hurt the system performance, but does this seem normal/acceptable? Any thoughts would be appreciated.....service techs coming next week....wanted to be prepared so I know if they are really getting it right.
hi and welcome! A 2 degree heat of extraction is way off for your split, as is the 5 degree air change across the a coil. Do you know what the design temp was for your split? This weather has shone a light on some systems where the design temps and real temps are quite far apart. I would start by calling the hvac and tell him how low your water heat of extraction is and get them out there. Some thing is definitely wrong. Eric
So I finally got the guys out....in heating mode, the suction pressure would start at about 100 psi quickly fall to 50 psi and the compressor would shut down and give a frozen up fault after about 1 minute of running.....water flow is fine. They switched it to cooling and the compressor would continue to run, but both pressure readings were well under spec. They tried to add refrigerant....I'm not sure if it took any or not..I am pretty sure they did not think it took any. I was watching the whole time, and I'm pretty handy guy but didn't want to ask too many questions and get in the way. The tech decided that the compressor was bad and he also wanted to change the txv and the filter/drier on the line set. 1) Does this seem like a proper diagnosis? 2) Is there anything I should look for as a cause for this failure so soon (either design or installation wise), or just chalk it up to bad luck. We haven't talked about money yet, but I have some pretty thorough paperwork the installer gave me 3 years ago that says pretty much everything is covered for 10 years parts and labor.
