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Hotinsummer 08-09-2009 01:41 PM

AC condensing unit failure?
My 5 ton split system compressor stopped working apparantly due to overheating.(fan unit running but compressor stopped) Cooled compressor down and restarted. compressor runs but indicates same pressure on both high and low side (150psi? friend with gage) Unit is over 15 years old so looking at replacement of just condensing unit but also wondering about inside unit, coil etc. Freon level is fine. Seems to me that pressure differential is controlled by coil unit in house :huh:
Can new condensing unit be installed to old blower unit since amount of changes to systems over last 15 years? what are options there?
Don't want to throw good money at an old system but also line of thinking is that new condensing system now would work with new fan unit installed at later date. If money were no object would replace entire unit or remodel whole house, or...but money tree has been looking scraggly lately.
Also unit is 3 phase, does this help with energy efficiency? (older neigborhood with 3 phase power)
thanks for any help.:)

Plumber101 08-09-2009 01:50 PM

With the system being 15 yrs old you might money ahead replacing the whole system. However, if you replace the condenser you will have to replace the coil inside and you need to look at the option of converting to R-410a freon.

Check with your local city because the only thing in your house is more than likely the A/C. Most cities will want to disconnect the 3-phase. Converting from 3-phase to single phase 240 v is not a big deal.

Are you 100% that the compresor is running? If you can check amp draw.

Ice Man 08-09-2009 01:52 PM

sounds to me with 150psig on both high and low side, that your compressor may not be operating. what is your amp draw across the 3 phases?? what is your RLA of the compressor?

Hotinsummer 08-09-2009 02:08 PM

the RLA for the compressor is listed at 20.7.
the actual amperage draw across all 3 ph. is 7amps.
The compressor is running ie making noise.

this is the only AC running on 3 ph. One other condensing unit was replaced with a single phase and one other package unit is single phase.

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