I have a customer with 2 30k walk in coolers, one was r12 converted to 409a and the other is R22. Both are at least 20 years old. Both have been experiencing problems due to age. I would like to upgrade his equipment to something more up to date and reliable and get away from 409a and r22 since the refrigerant prices are ridiculous. I was told by the local supply house I could replace the condensing units and replace the txv's with 404a stuff, flush the systems and I would not have to replace the evaps. Then a few days later the supply house calls and says the distributor orifices would have to be removed in the current evaporators and replaced, and if the TXVs were sweated in that would be next to impossible to do so then I got them to requote the jobs with new evaps as well. This seems awful expensive at a time when lots of places are just struggling to get by.

Are there any alternatives to this scenario?
For the R22 unit can I just get another R22 unit and switch the refrigerant to MO99? Although MO99 isn't much cheaper.

I'd like to avoid having to replace the evaps, but there doesn't seem to be much of a choice....