dear all

i have a heatpump calorex model AW7034BHC.R134a.tandem compressor model:copeland zr12m3e.problem is the both compressors are defective.right now the same tandem compressor not available in DUBAI,have to wait 2 month.but work has to be completed immediately.i am thinking to convert to R22 sytem.fixing single same capacity compressor instead of tandem.replacing txv,flshing the circuit...etc.but is it possible a 134a system to R22 system?if ,which ZR series compressor i can use for this job?

any help would be appreciated
Moideen-Dubai