Hi guys, I'v been in the trade for almost 4 years now and still don't truly understand most things about changing a system from the likes of R12 to 134a.

I have a job with an R12 unit that runs a glass doored drinks display, the compressor has seized and I have to price the job.

I know I have to change the compressor (duh), the filter dryer and flush the old oil out of the system.

What I'm wondering is if I will have to change the capillary tube or if the condenser and evaporator are going to be of the right size?

If I do have to change these I doubt I will be able to to this job as I'v no idea how to calculate the length of capillary needed and only the vaguest idea of how to size the evaporator/condenser (I'v lost all notes from college )

any advice you can give would be helpful.