Also says to change out all of the valve cores and in some cases, the txv's. Make sure YOU read it all carefully rather than having someone tell you what they ready.

 

TXV not necessary with 427A as stated by manufacturer but yes they do say they recommend to replace and rubber seals

 

Retrofit



I have seen 407C to be the best

 

I've been using R422b. (NU22) The best thing about r422b is that it is compatible with any oil. The pressures are very close to R22 but obviously you should use the P/T chart that is printed on the box the tank comes in. It seems in my area everyone is using R422b. I know it's not advised but I've actually dropped it in on top of a system low on refrigerant that had R22 in it and it worked totally fine.

 

Thanks for contaminating the entire system! If there was a way of turning your a$$ in I would.

Now some poor smuck will have a mixed recovery cylinder!

 

Depends on Age of System and which Oil it Has for retrofit.And I like the Prowler Leak Detector. You Get What You Pay For!

 

After lurking here as a member for nearly 4 years with a pitiful post count, I guess I might as well step in it and get some posts and probably some folks scratching their heads at my post. BTW, I am a dinosaur (over 55).

If we are discussing resi work, we are talking reasonable quantities of R22 for a dry system, say 5-9 lbs. Not sure why anyone would retrofit a resi system and not just use R22. R22 is an exceptional refrigerant and still really isn't THAT expensive. It's not like these alternative refrigerants are free. I know pricing is not allowed on the site, but let's say the alternate refrigerant costs 10 apples per pound. Right now R22 costs about 25 apples per pound where I live. That's 15 apples per pound more than the alternative refrigerant. Let's say we have a system that holds 6 pounds. Are you really going through the trouble and potential small efficiency reduction in retrofitting over 90 apples? By the time the system dies in X years with the R22 fill, the HO can replace with a new system based on future refrigerant standards. Never retrofitted a system and never will.

If you are talking hundreds of pounds in a commercial setting, that's an entirely different story.

There are three refrigerants in my van: R22, R410a, and R134a. When the R22 is gone, I will retire.

 

I think you forget to include Mark up so you will need to double the number of apples, to a customer that might be a lot of apples.

 

I think we all know what happens to most mixed recovery cylinders

 

We use r453a, says it actually has a slightly higher capacity than r22. Weve had no issues and no need to mess with the oil.


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We use r427a with Poe oil and replace filter driers and valve cores. Good results with it so far. M099 I would stay away imo.

 

If anyone cares, the cost of R22 has dropped drastically in the past couple weeks.

 

I care; how "drastically?"

Last time I picked some up I think it was around $ a jug.

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We dropped our price $ in the past 2 weeks. From $ to $ in the Chicago area but I've also heard from some of our customers they can get skid pricing elsewhere at $ a jug.

 

The word is schmuck, not smuck. Its Yiddish.

 

According to data, 407C has the least capacity loss. The others lose capacity at higher rates as outdoor ambient temps rise. I have used nearly all of them. I have had good results. One time on a residential 5 ton carrier 10 seer I had complaints. After a catastrophic R22 leak from copper tube vibration against a sharp edge, I changed the system over to 421A.
All was fine until we had a 96F day. House would not cool below 77-78F.
Was a 2500 square foot pre 1940s home with casement windows, no insulation, flat black epdm roof.
Before the conversion, house could maintain 72F.
New drier, charged to superheat. All coils were cleaned.

 

I'm doing a big job this month. It's a 10 ton Dectron (two 5 ton compressors) de-humidification unit. Though 20 years old the compressors are running great. It has great evaporator and reheat coils. The r-22 is the biggest negative. We're pulling the compressors and dumping the mineral oil replaced with POE. We've decided on R-422b (the nu-22). I'll let you know how it goes.

 

NU22 works fine. I have it in medium temperature applications as well.

 

Isn't R22 about the same price currently ? Plus 5 more extra pounds single component.

 

R-22 is a lot more now. In 20 years (wishful thinking), it wont be available at all.

 

No it's not I just got pricing on it.

 

I dont believe in any drop-ins.

 

R-22 equipment will be around for many years. Some of these units are disposable, however some are less easily replaceable. The unit I'm working on is 20 years old. It has a dual path 8 row evaporator coil. It has a 6 row reheat coil and water heat exchanger within it. It also incorporates a 7 1/2 HP blower motor. The house was built around it. It provides dehumidification for an indoor pool. Right now you can get R-22. I'm not sure what that availability will be in five years. I'm hopping that R-422b will be here. If not, with the POE oil in it almost anything can go in it.

 

The KT-53-VC TEV element went from a green color to a blue color. Just saying.

 

There's lots of other refrigerants you can use but it depends how much work you want to put into it.

Some R22 units use Mineral oil, some use POE. 407C uses POE and MO99 uses Mineral oil so if you want to go through with the whole oil flushing process then I would opt for 407C because it does have a slightly higher capacity. We could get into Mollier charts if you want?

Other than that, it really just depends on how much work you want to do and what the customer is willing to pay for, there's a lot of options but strictly speaking in capacity 407C has the highest.

 

Depends on the piping. Suction line velocity etc. I have many split systems running with MO and a few ounces of POE added and 407C. No dead compressors.

 

So, when those freshly converted residential systems develop a leak, losing a few lbs. or 1/4 of the charge from a loose Schrader core then what? Are you going to top it off with a mixture that has a 10° glide?
From what I see lately, evaporator coils go before most compressors.
Still don’t see the point in residential conversions. It’s a game the big chemical companies are playing.

 

Sure, there's lots of factors, but a refrigerant is a refrigerant, I doubt suction line velocity is a factor in selecting a replacement refrigerant I would imagine that since the piping worked out and was done correctly or at least to the point there was sufficient oil return, that another refrigerant would work as well. I've at least never heard of suction velocity as a determining factor.

There is no such thing as drop in refrigerants, it's beat into your head during the EPA certifications. Mixing refrigerants is not allowed, so dropping MO99 onto R22 is not allowed.

Glide is how the new blends are, just have to account for it.

 

MO = mineral oil

 

Oh, I see.

I thought you were referring to MO99.

Mixing oils is also bad practice is it not?

"Mixing of Polyol Ester and Mineral Oil

Published 05/19/2014 10:05 AM | Updated 05/19/2014 10:05 AM

Can I mix Polyol Ester (POE) and Mineral Oil (MO) together?

When using CFC or HCHC refrigerants, POE and MO can be mixed. The exception is R12 that only uses MO or Alkyl Benzene Mineral Oil (ABMO) blend. HFC refrigerants can only use POE oil."

http://emersonclimate.custhelp.com/...sthelp.com/app/answers/detail/a_id/980/~/mixing-of-polyol-ester-and-mineral-oil

But 407C is an HFC and it requires POE.

 

Yeah, mixing the two oils is not a good idea. The compressors name plate indicate they were charged with 70 oz. of mineral oil. We plan to remove the compressors and measure what we take out of the system. After a nitrogen blow out of the coils and heat exchangers, leak check and evacuation down to a least 250 microns we will then charge with POE based on name plate. The residual mineral trace oil should not be a issue. We will then charge the system with R-422b which can handle some MO.

 

I could see someone retrofitting just to get it over with but I wouldn't personally do it until there was some sort of problem which would just make the retrofit another step in the repair. Like replacing a compressor or condenser or something like that.

 

I just feel opening up the system, removing the compressors to drain the oil, then putting it all back together will A. be pretty expensive, and B. cause a lot of headaches.

Also, if one of those working perfectly fine for 20 years compressors dies next year, there will be finger pointing. A lot of finger pointing.
If the customer see's a value in it then go for it.

 

The oils mix fine. No issues. That's a myth how it creates goop and clogs etc.
MO, AB, POE and PVE all mix. I do refrigeration so we run into that on changeovers all the time.

 

:cheers:
It’s the refrigerant that needs to be checked for compatibility r22 can run min. Ab. Poe or a mixture of all three ( all though not sure why anyone would have all three).99% of the crap they told us 20+ years ago was half truths at best. If you look at mo99 they recommend adding Poe for oil return in some cases.

 

The main reason for the conversion from R-22 was not noted. The system has incorporated outdoor coils for heat rejection. The unit also has water heat exchangers to permit heat rejection into the pool water. The outdoor coils created a chalanging charge in that the refrigerant would migrate to the cold outside coils in winter. Getting the system up to a clear sight glass during cold environments would cause an over charge in the warmer climates. After chasing the charge for 20 years, the coils are being eliminated. The heat rejection will be into the pool only. The pool has sliding glass panels that tuns the pool into an outdoor pool in summer.
That being said, since the system is being torn apart we want to get away from R-22. The glide is the my major concern on the R422b. The system does include oversized receivers and TXV's.
Any suggestions on the SH setting we should shoot for considering the 10 deg. glide?

 

Why are you charging an A/C unit to a clear sight glass?