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R22 retrofit to R427 or Mo99, or invest in new system

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dtopford

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Discussion starter · #1 ·
Hello All,
A little background, I was in the Navy for 20 years as an engineer and did attend AC&R school and learned about enough to be dangerous which brings me here.
I have a 2003 Rheem 4 ton system model RPKA-049JAZ using R-22 that recently experienced a failure.
A power wire wore through the insulation and arced against the piping going from the reversing valve to the accumulator and burned a hole in the piping releasing my refrigerant.

After investigating and talking to a couple different HVAC service providers I have been given two options. Replace the system or do a retrofit as a Band-Aid using a refrigerant compatible with R-22.
The two refrigerants suggested were R-427 and Mo99. I have read that M099 is closest to R-22 however R-22 permeates the rubber seals within a system and Mo99 does not, which would require the replacement of any rubber seals within the system to help mitigate leaks in the future.
My question is if you were going to retrofit the R-22 system which refrigerant would you use and why?
My budget can't afford a new system right now so my only real option is the retrofit unless I can find some interest free financing options out there.
The situation was caught right away and I removed the mechanical power disconnect to prevent any operation of the compressor until the system is restored, so I do not suspect any compressor damage at this time.

Thoughts?

Thanks in advance,
Dan

Additional thought, would either of these substitute refrigerants work better with the existing metering valve/orifice? I do not know what my system is equipped with.
 
#7 ·
I like 407c, they say add a little poe oil but I have done several, some with 4oz supco88 and some with nothing. All are doing great. Out of those two mentioned mo99 is the only one that I am familiar with and haven’t seen issues with it either. I wouldn’t hesitate to use a drop in if it were mine especially since now they are talking about ditching the 410a and going with R32 or R454b which will make the 410a price to go up also.
 
Discussion starter · #8 ·
VTP99 said:
So how much cheaper is the alternative.
Percentage wise not dollar amount.
Your system holds 8 lb approximately.
Click to expand...
Almost 50% less than R-22 including the repair. Plus I just found out that the Gov is phasing out R-410 starting next year, but anything I buy today will be R-410 which makes the bandaid solution more appealing. patch it up and save for a new system with the new approved refrigerant next year sometime. Now just have to decide which alternate refrigerant to go with.
 
Discussion starter · #9 ·
I spoke with a technician recommended by a friend yesterday who also suggested 407. He told me that he has used it in the past without issue. He repaired my friends unit about 6 years ago in a similar situation and has not had any issues since the repair was made.
 
#10 ·
dtopford said:
I spoke with a technician recommended by a friend yesterday who also suggested 407. He told me that he has used it in the past without issue. He repaired my friends unit about 6 years ago in a similar situation and has not had any issues since the repair was made.
Click to expand...
If 407 is used without oil additive, the compressor will not live long.
 
#11 ·
Keep this in mind, if you use an alternative, and there is a leak...

EVERY TIME you are a little low, you need to remove and replace the entire charge...

With 22, only what is lost need be replaced.
 
Discussion starter · #12 ·
vstech said:
If 407 is used without oil additive, the compressor will not live long.
Click to expand...
Yea, I've done some research on 407 after we talked and I would insist on a complete evacuation of the system and adding the correct oil for the 407.
right now the suggestions for an alternate refrigerant are 427 which is mineral oil compatible, Mo99 which is mineral oil compatible, and 407 which needs POE oil.

Decision decisions.
 
#13 ·
dtopford said:
Yea, I've done some research on 407 after we talked and I would insist on a complete evacuation of the system and adding the correct oil for the 407.
right now the suggestions for an alternate refrigerant are 427 which is mineral oil compatible, Mo99 which is mineral oil compatible, and 407 which needs POE oil.

Decision decisions.
Click to expand...
I can’t even count the number of units, most over 10yrs now that I used 407c in. I prefer adding 4oz supco88 but the high velocity of the refrigerant seems to be enough. I did over a hundred on one property, now over 10yrs ago, not a single compressor issue and no complaints of capacity loss. Having said that I feel mo99 would be fine as well but from what I have read is a slight more capacity loss. Last I checked mo99 is becoming fairly expensive now, still much cheaper than 22.
 
#16 ·
Consider a R407C new condensing unit ( straight A/C thou as they don’t make them in Heat Pumps ) comes with a 5 year parts, coil and compressor manufacturer warranty, and I believe one lb. of R407 C refrigerant in the condenser. Probably cost would be somewhat comparable, than repairs and whatever refrigerant you decide on a 21 year old system. Course that depends on if you have electric heat in your Air Handler and its sized to carry the load solely and your state has cheap enough electric rates.

https://www.guardianhomecomfort.com/equipment/r-407c-systems.aspx 2024

Parent Company Johnson Controls, which owns York and a bunch of other HVAC brands.
 
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#17 ·
We've used R407c for 9 years in our school district with no problems!
Straight cool and heat pumps.
Just added a little Supco 88 for oil return.
:cheers:
 
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#18 ·
EMETH said:
We've used R407c for 9 years in our school district with no problems!
Straight cool and heat pumps.
Just added a little Supco 88 for oil return.
:cheers:
Click to expand...
Exactly and if I am not wrong it’s the only replacement that many compressors, txv’s label as ok. My experience has been the same, 4oz Supco88 which is dirt cheap.
 
#19 ·
I would, and routinely do, use R-407C in place of R-22.

For residential -esque systems I have never found a flaw.
Switch to POE oil - no problem.
Leave mineral oil and add a few ounces of POE oil to it - no problem.
Leave mineral oil and add a few ounces of Supco 88 to it - no problem.
Do nothing and just run R-407C over mineral oil - no problem.
The unit running over my head right now is a straight R-22 system - mineral oil in the compressor - running R-407C - and I put it together at least five years ago.

It is my opinion that a properly sized piped Refrigeration system MIGHT have oil return issues. But residential and light commercial systems are so first-cost design-driven that their piping is always undersized with the resulting high vapor line velocities. And so the resulting turbulence effectively resolves any oil return concerns. <g>

PHM
--------


dtopford said:
Hello All,
A little background, I was in the Navy for 20 years as an engineer and did attend AC&R school and learned about enough to be dangerous which brings me here.
I have a 2003 Rheem 4 ton system model RPKA-049JAZ using R-22 that recently experienced a failure.
A power wire wore through the insulation and arced against the piping going from the reversing valve to the accumulator and burned a hole in the piping releasing my refrigerant.

After investigating and talking to a couple different HVAC service providers I have been given two options. Replace the system or do a retrofit as a Band-Aid using a refrigerant compatible with R-22.
The two refrigerants suggested were R-427 and Mo99. I have read that M099 is closest to R-22 however R-22 permeates the rubber seals within a system and Mo99 does not, which would require the replacement of any rubber seals within the system to help mitigate leaks in the future.
My question is if you were going to retrofit the R-22 system which refrigerant would you use and why?
My budget can't afford a new system right now so my only real option is the retrofit unless I can find some interest free financing options out there.
The situation was caught right away and I removed the mechanical power disconnect to prevent any operation of the compressor until the system is restored, so I do not suspect any compressor damage at this time.

Thoughts?

Thanks in advance,
Dan

Additional thought, would either of these substitute refrigerants work better with the existing metering valve/orifice? I do not know what my system is equipped with.
Click to expand...
 
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