Thumping noise in the compressor

[Husky250]

A couple weeks back I posted regarding a thumping noise coming from a Sanyo inverter compressor. Today, I got another call regarding the same issue. Here are the details. New system, never ran. Sanyo PAC-I single zone system 36,000 BTU. Short piping run and Factory charge OK for piping run .On call for colling system goes through normal 3-minute time delay, and outdoor starts operation. Outdoor fan starts, and thumping noise can be heard from compressor. Fault code displays P-29
( Inverter Start Trouble ) The service manual indicates either compressor or compressor starting with a load ( liquid ) Recovered charge and re-started with same result , P-29 and same thumping noise inside compressor. The voltage supply to the compressor from the IPM is equal between all phases. Thanks to you fine folks I know how to check all that. At this point Im confident the problem is in the compressor. My problem is this: This is a new system that never ran. No crankcase heat currently on this model, but I think compressor is using a trickle circuit to provide heat for the compressor.Ambient conditions were cool at the time of installation. Service Technician swears they had power on 12 hours before test run, but I cant confirm. Do you guys think this could have taken the compressor out? Have any of you had a thumping compressor. It almost sounds like the compressor is only getting two phases of the three phases needed to run. Megger test good with nothing to ground, and resistance checked good per service manual, equal across all windings. Anyone got some advice? Thanks to all for any help!!

[Husky250]

One thing I forgot to mention....The service manual also states to check the DCCT sensor. I had no problem finding a CT sensor located on the AC input power coming from the terminal strip, but no DCCT sensor.

[ozairman]

Can you descrbe the "thumping" noise? A normal Inverter compressor start is sort of a whine that builds up in pitch it is pretty unmistakable. One that is having issues with getting going or is seized has been described to me in many ways such as:
"an engine running on only few cylinders" ie 3 out of 4 etc
"an old fashioned telephone dialling"
"a typewriter"
"a machine gun"
"a chattering noise"
It is also pretty unmistakable after you have heard it a few times :-(

Whilst not generally supported by manufacturers and as a last resort you can try swapping two phases over at the compressor. They are still a 3 phase motor and will start up and run backwards but only for a short period of time as the electronics will detect the compressor rotation being out of sync with the switching pulses. On that note have you double checked the compressor is connected the right way round?

[Husky250]

The thumping noise sounds exactly like someone taking a rubber hammer and hitting the top of the compressor when starting. The compressor never really runs, only thumping. My thoughts exactly on the compressor wiring. Its correct all the way from the IPM to the compresssor wire for wire. I didnt think of changing the phases. I have accidently reversed those and compressor ran, just not pumping. The thing that bothers me is this is a brand new system ( out of the box ) never ran. Not my first time hearing the thumping compressor either. Im getting this system back to troubleshoot. If I can figure how to do it, I could record the testing of this unit for you all the see and hear.

[ozairman]

The thumping noise sounds exactly like someone taking a rubber hammer and hitting the top of the compressor when starting. The compressor never really runs, only thumping. My thoughts exactly on the compressor wiring. Its correct all the way from the IPM to the compresssor wire for wire. I didnt think of changing the phases. I have accidently reversed those and compressor ran, just not pumping. The thing that bothers me is this is a brand new system ( out of the box ) never ran. Not my first time hearing the thumping compressor either. Im getting this system back to troubleshoot. If I can figure how to do it, I could record the testing of this unit for you all the see and hear.

A digital camera on movie mode works ok then upload it to youtube, there is also some software around to strip the audio off a video if you just want to put the audio up as an mp3 file.

[Husky250]

Time permitting, I will see if I can do it.

[Husky250]

I put the thumping compressor to rest today. Got the unit back. Checked compressor to earth ( good ) Checked HIC board with all you guys help( good ) connected inverter checker ( not good ) lights acting very strange. DC VOLTS good coming to HIC. So I connected another compressor outside the unit and ran it, same thumping noise this confirmed in separate compressor. So my thought was HIC ( ipm ) checked OK what makes switches open and close? Main controller. Replaced and system ran fine. The fault code was P-29 missing phase @ the compressor. I would have never thought the main controller was at fault. I was certain the fault was in the HIC or compressor itself. I was wrong.