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Not a 'drop-in' but, Dupont says 407C has a range of performance of 98–106% compared to R22; the cost is currently about ¼ of R22.

Then again, nothing is a 'drop-in' if you have to take any further steps to make it work.

Dictionary defines drop-in as: adjective: requiring only insertion to be ready for use.

If you can remove 10-25% of the MO, why not remove ALL of it and fully recharge with POE?

DITTO!!!!!!

407c is a great replacement for R22. The problem is with the oil difference. I have only used 407c when changing the compressor. That way I can dump out the mineral oil in the compressor and replace it with the appropriate POE oil for 407c.

Originally Posted by cajunhvac75

I was at a class recently and met two different guys (both business owners) that swear by MO99. One guy uses it with new dry R22 condensers or after completely evacuating a system. The other guy actually just drops it right in on top of R22 already in a system (I know this is wrong, but he claims to have never had a problem doing it).

Of course he doesn't have a problem with it it runs long enough for him to get paid then the next guy that comes along to recover the crap gets hit with a fine for having mixed refrigerant in his cylinders

Originally Posted by cajunhvac75

I was at a class recently and met two different guys (both business owners) that swear by MO99. One guy uses it with new dry R22 condensers or after completely evacuating a system. The other guy actually just drops it right in on top of R22 already in a system (I know this is wrong, but he claims to have never had a problem doing it).

Why would someone sell a new dry r22 system charged with mo99, which voids the warranty and lowers efficiency, when they could just sell a new 410a system with full warranty?

Must have had a lot of old stock???

I can see we are still at the starting point and I'm getting same stuff from other Vendors out there and also from supply house's anyone has a Dif opnion.

The following is a little bit of information concerning refrigerant replacement for R-22.

There are a number of so called drop in replacements for R-22 on the market.
The following is a sample list: Dupont M099 which is actually R-438A, ICOR NU22 which is actually R-417A and ICOR NU22B which is R-422B.
You also have R-422A,R-422C, and R-422D.

The upside to retrofitting is: Cost of replacement refrigerants are presently about ½ the cost of R-22. Retrofitting may help put off replacement of equipment until the customer’s budget will allow.

The downside to retrofitting: All replacement refrigerants at present experience a capacity loss which may be 7 to 30 % if installed correctly.

It is possible that leaks will occur at elastomeric seals after replacement. These seal include Schrader cores, solenoid valves , ball valves, receiver gaskets ,etc.
Leaks are not a given but the older the system the greater the chance for leaks.

Systems that have present oil return problems such as long line length or oil logging in the evaporator due to air flow or ambient operating conditions may have to remove 10 to 25% of the existing mineral oil and replace the removed oil with the same amount of polyol ester oil. If this needs to be done extreme care should be taken when installing the polyol ester oil as it is extremely hygroscopic.

SUMMARY

There is no true drop In refrigerant replacement on the market that meets the exact design of R-22. All replacements have potential issues even though the customer might find these issues are slight.

The contractor must replace driers and install driers that are compatible with the replacement being used.

The newer the existing system is the less chance of problems and more cost effective retrofitting will be as R-22 will continue to rise.

The older the system the greater the chance there will be a problem such as leaks , oil return, etc.

The refrigerant replacements are HFC which depending on the one used is a Near Azeotrope and or Zeotrope which must be charged in a liquid form.

After a system is put into service it may require adjustments to expansion valve to maintain proper superheat .

mixing two will not work,as both the refrigerants are having different boiling point,critical point etc. Compressor oil is also different.As the POE oil used in R410A systems is very sensitive to moisture,thats why it is recommended to achieve atleast 300 micron vaccumm level in 410A system.
Still wondering how system will behave at high ambient conditions?

R-22 Alteratives Pro's and Con any help

Originally Posted by Cooked

What type of building is using 120BTU twinned furnaces in Gainesville?

2 story office bldg. with a central mechanical room. Ducted and zoned. It's a mess. There are a total of 5-120k furnaces. 2 are twinned for the ground floor, the other 3 "tripletted"(is that even a word?) for the top floor. Attachment 354301

You controls guys will love the zone control board (it really is a board- plywood)Attachment 354311

No idea who designed, engineered, or installed it. They didn't leave a sticker anywhere.

Originally Posted by Pete838

I've got two 5t dry units going in wed. with 422d. Commercial setup so no ARI match needed, twinned 120k gas furnaces with evap. coils buried behind ductwork. Low budget. We will see how she goes.

What type of building is using 120BTU twinned furnaces in Gainesville?

I've got two 5t dry units going in wed. with 422d. Commercial setup so no ARI match needed, twinned 120k gas furnaces with evap. coils buried behind ductwork. Low budget. We will see how she goes.

If you combine them you'll end up with an azeotropic mixture, partial pressures and potentially different leak rates. And of course you can toss the factory charging chart out the window. Good luck doing that on a critically charged system.

A few dry units approve of 407 in them.

Im only an apprentice but the qualified guy's Im working with have be been dropping in MO99 with no problems.

The last dry condensor I did I asked the supplier about a alternate refrigerant and was told warranty was only valid with R22.

Originally Posted by cajunhvac75

I was at a class recently and met two different guys (both business owners) that swear by MO99. One guy uses it with new dry R22 condensers or after completely evacuating a system. The other guy actually just drops it right in on top of R22 already in a system (I know this is wrong, but he claims to have never had a problem doing it).

I've heard similar things about NU22, including "topping off" with it. I am planning to use it the next dry unit I install. As far as mixing, I'm going to wait and see for awhile.

I was at a class recently and met two different guys (both business owners) that swear by MO99. One guy uses it with new dry R22 condensers or after completely evacuating a system. The other guy actually just drops it right in on top of R22 already in a system (I know this is wrong, but he claims to have never had a problem doing it).

You shouldn't need to add refrigerant unless of course there is a leak. If they are fairly new as you say, and just needs a leak repair, i would give the replacements a try if that is what the owner wants. You can do a search on here. There has been much talk already about this.

In all honesty, the biggest favor you can do for them is steer them to a new 410 unit. Its just a matter of spending some money now to spend less down the line. 407c is the best we have come across as a drop in replacement, but at best you are getting 90% efficiency of the BTUs the system is rated at. I don't know about Ohio, but that doesn't cut it down here when the needle gets past 100 degrees.

Clients are just out of the warrantey period and still have life in the Units they are very good about replacement when Units reach the age of 10 years old but with the price of R-22 going up the are seeking out others ways and asking before they take the leap. I have heard allot of mix feelings and thought I would ask the mass's on here

Tell them a brand new 410a unit works fantastic