Carrier Conversions

[frank]

I've been asked to convert 3 x 70kw Carrier air cooled DX condensing units from R22 in preparation for the phase out of R22.

The units are single stage 6 cylinder semi - hermetic compressors (76A flc) with no unloaders. They appear to be recon compressors and operating quite satisfactorily.

Which gas should I choose?

It's an air conditioning application presently evaporating at 5C.

:)

[Brian_UK]

A little bit here Frank by someone else regarding a chiller gas change might be of interest.
http://www.modbs.co.uk/news/fullstory.php/aid/2030/Refrigerant_replacement_extends_chiller_life_.html

plus this item from earlier...
http://www.refrigeration-engineer.com/forums/archive/index.php/t-1727.html

[frank]

Thanks Brian :) - I was considering R59 but I've heard bad reports of oil recovery.

[Renato RR]

R407c and you can keep TEV.

Renato

[frank]

R407c and you can keep TEV.

Renato

There may be a residual oil problem with 407C

[Renato RR]

Well you will nedd change it 4-5 times before becomes ok.Cut off all sifons and empty old oil from traps.

Renato

[Andy]

I've been asked to convert 3 x 70kw Carrier air cooled DX condensing units from R22 in preparation for the phase out of R22.

The units are single stage 6 cylinder semi - hermetic compressors (76A flc) with no unloaders. They appear to be recon compressors and operating quite satisfactorily.

Which gas should I choose?

It's an air conditioning application presently evaporating at 5C.

:)

In a case such as this a phased change is better. First change the oil to ester oil, keep the R22 and keep changing the oil until the lab tells you the mineral oil % is below 1 to 3% (your oil manufacturer will help you with this figure).

When the oil is flushed, then it is time to change to the new refrigerant, probably R407c, even though I don't like it, it is probably the only alternative atthe moment.

Hope this helps.

Kind Regards Andy:)

[guapo]

Hi,
I used r407c for replacement of r22. No problem yet.

[Superheat6k]

Conversion from R22 to a HFC such as R407c is frought with problems, and could be a very costly exercise.

Du Pont now offer the Isceon range and we have found Isceon 59 (R417a) excellent as a 'Drop In for R22 on DX systems.

This gas is not cheap and the recommendations by DU Pont to thoroughly leak test must be followed.

You may also have to adjust the TEVv and should use tables for R417a to check superheat & subcooling levels. Sometimes the cage / orifice size may need to be increased.

[frank]

After studying various reports I chose to convert with R417a. One unit has been sucessfully converted with excellant results but I'm waiting on Carrier to provide further gaskets etc (due in from the States soon I'm told) before I can proceed with the other 2.

http://www.eurocooling.com/articlerhodia.htm