View Full Version : Changing closed system A/C unit working with R410A to R22

01-05-2014, 02:50 PM
Hi Everyone
I'm having a closed system A/C unit HPAC, I mean the air conditioner for technological applications such as data centers etc. The unit is working with R410A but the compressor is dead and such a compressor works with R410A isn't available, so I'm going to convert this unit to work with R22, will bring compressor with same capacity works with R22 and will bring Expansion valve also work with R22, but am wondering what the ratio between the capacity of the compressor and the expansion valve?, I mean if I have compressor 7 TOR what the size of expansion valve should I bring, I mean how many TOR?

Looking forward to hear from you soon.

Warm Regards

The Viking
01-05-2014, 07:55 PM
Hi Das,

Welcome to the forum.

Unfortunately what you are proposing to do will significantly degrade the system. One of the great benefits of R410a is that the systems designed for it requires much smaller coils, both evaporator and condenser, as well as pipes.

Hence, to swap the compressors like for like R410a/R22 will mean the system is severely undersized to cope with that compressor. The alternative would be a smaller R22 compressor but that selection process will be a long string of trials and errors...



04-05-2014, 11:09 AM
Hi there, thanks for your response.
It's true that this converting process will lead to a reduction in the efficiency of system since the discharging of R410a is higher compared to R22, maybe between 10-20% reduction in efficiency.
I'm wondering if you have more info about the effect of M.O.P of expansion valve in this process?

Many Thanks

06-05-2014, 12:18 PM
I have made numerous conversions from R22 to R410a by changing compressor, removing capillary and adding EEV to the system, but I have never converted a system to R22 from R410a. I am guessing that if you undersize the R22 compressor a bit and add EEV, which you can set up on trial and error basis by looking at the pressures and temperatures you will be fine ;)

10-05-2014, 02:26 PM
Thanks everyone
I've convert this unit successfully from the first try. I've undersized unit by bringing compressor 6.75 TR instead of 7 TR and thermostatic expansion valve 7.5 TR instead of 9 TR but with same temperature range and working pressure and of course not the same M.O.P, also I've changed the filter. The unit now now is working in perfect way.
Thanks all for your helpful thoughts
Salam from Sudan