View Full Version : carrier 38qca036-023 high pressure problems

10-01-2017, 11:13 AM
Hi. I have been struggling with a carrier ducted rc that is making loud noises (apparently).
3 phase comp, single phase outdoor and indoor fan motors. Unit is heat and cool.
Fans amp draw is ok, power to them ok, capacitors, coils, ductwork, airflow all ok.
Fans rotation direction is also ok.
Unit is a carrier 38QCA036-023 (outdoor fan pushes air over coil instead or pulling air over coil from factory) about 200mm from wall. Plenty of room around outdoor unit.
Lowish amp draw. Rated amps 8.5 on each phase. Am getting 6amps per phase.
On cooling:
Air on outdoor coil 30 degrees C
Air off outdoor coil 42 " "
Air on indoor coil 25 " "
Air off indoor coil 19 " "
Subcool 8k
Superheat 20k
Suction pressure 470 kpa
Discharge pressure 1900 kpa
Tx valve unit

As pressures are both high its doubtful comp or rv are leaky. Rv has same temp across both sides of suction. When i cool the outdoor coil with water to approx 1500-1600 kpa the unit runs like 300kpa suc / 1500 kpa head. Suspected outdoor airflow issue causing condensor to not be able to remove its heat by being too close to wall? But low amp draw confuses me on this issue seems unit appears to pump down fairly quickly. Its a recip.
Possible 2 faults?
Suspect the noises are due to excess compressor noise/vibration on 40ish degrees C days due to excessive heat in condensor.
Any help would be awesome. Cheers

10-01-2017, 04:26 PM
Have fan blades been fitted the wrong way round if you say the rotation is correct

11-01-2017, 05:56 AM
Na the grub screw is in the usual spot isee it in, if it was wrong way around i wouldnt be able to access the grub screw at all so it fairly easy to see its the correct way around. Very weird issue