Conflicting Information on R22 Replacement

[Windseeker]

Is it me, or is there conflicting information on the conversion of R22 to R422? This is going into a residential 3 ton Heat Pump. I have selected R422B as the suitor as this most closely resembles the R22 characteristics for HVAC. The unit has a TEV with a Receiver. From the Tecumseh document RD-0003-E section A3, I would need to flush the system and replace with POE. Information from the National Refrigerants, Inc., blends tutorial pg. 86 indicates that I might need to just add a little POE.

Thoughts on this?

Some seems to state the unit needs to be evacuated, dryer replaced and possibly use a larger expansion valve. Other information seems to indicate that you can just evacuate and recharge with no changes at all. It’s like Voodoo and Black Magic.

Any other thoughts?

Thanks. You guys are the Greatest!

[Brian_UK]

I would follow the Tecumseh advice, it agrees with most other documents regarding using these 'drop-ins'.

The main reason is the fact that you have a receiver will give oil logging problems, ie the oil will settle on top of the refrigerant in the receiver.

It may be worth allowing for more than one filter change because the POE will clean up the inside of the system.

[Grizzly]

8387

If you are to add POE oil, you best read the attached.
Paricularly page 3.
It implies that you can with your choice of refrigerant.

And yes there is loads of conflicting info about.
Good luck and please can you let us how you get on!
Grizzly

[a/c.nick]

aint you suppose to replace r22 units with mo99? flush with nitro vac the system out and change the dryer and hey presto. we have found that mo99 does not heat as well as r22 but cooling its fine.

[chemi-cool]

you do not need to change any oil, or add any poe.
the only problem you might face is with rubber parts such as o rings, check these parts for leaks.
evacuate, replace drier, charge and switch on.

have done 4 systems by now, apart from small leak in a sv o ring, it does the job fine.