What is required to modify when using 407C and 404A as drop-in for R-22

[mofotech]

HFC-407C and HFC-404A if they are used a drop-in replacement for R-22. Other then maybe changing the compressor oil out, are there any other requirements? Is this a cost effective then to buy R-22 currently, which may go up in price later on? I was just wondering about this and I wanted feedback from you guys.

[danbb]

404a would probably require a new TXV at the least

[Snapperhead]

404 is just as expensive as 22

[welling service]

Why would want to use 404? It is really not a good replacement for 22 in AC system. I have never heard of using 404 in place of 22. 404 is always used in low temp systems.

[crazy eye]

Why would want to use 404? It is really not a good replacement for 22 in AC system. I have never heard of using 404 in place of 22. 404 is always used in low temp systems.

A lot of med temp reach in use 404a

[MAC AIR]

I pay alot more for 22 than I do 404. Never heard of dropping in 404 to replace 22.

[mofotech]

I pay alot more for 22 than I do 404. Never heard of dropping in 404 to replace 22.

I never heard of it either, loll but it says it in my textbook. I just wondering what you folks thought about it.

[dgussler]

hmmmmm... next junk R-22 unit you have, dump some 404 in it and report your findings lol.

[jpsmith1cm]

With a metering device change, r-22 to 404a is possible.

R404a is an excellent MT refrigerant. Don't think that it isn't. I haven't seen it in AC applications, though.

Besides oil changes and MD changes/modifications, you'll also want to replace any elastomeric seal on the system. The change from R-22 to 404/407 causes the seals to shrink back to a normal size and will VERY often cause VERY LARGE leaks.

[beenthere]

R404A would be suitable to replace R22 in a refrigeration application, but not a high temp one such as comfort cooling on an air to air system.

[craig1]

That is a weird book you have In the pic. Neither of the refrigerants that are listed as "drop ins" actually are.

A "drop in" requires no modification to the system. Hot Shot is a drop in for r-12.

To replace R-22 with 404 would require at a minimum new TXVs, oil, and seals. It also has a pretty large capacity loss.

[mofotech]

R404A would be suitable to replace R22 in a refrigeration application, but not a high temp one such as comfort cooling on an air to air system.

What type of refrigeration application? And also when you say comfort cooling , you mean just plain AC units ? Thanks for the replies.

[mofotech]

That is a weird book you have In the pic. Neither of the refrigerants that are listed as "drop ins" actually are.

A "drop in" requires no modification to the system. Hot Shot is a drop in for r-12.

To replace R-22 with 404 would require at a minimum new TXVs, oil, and seals. It also has a pretty large capacity loss.

It is my school book. 'HVAC' NCCER Contren Learning Series . Currently in Level 3 book. One more to go afterward!

Well, thats why I asked the question here to get feedback from folks on the field. I also understood the "drop-in" as just charging the unit with replacement refrigerant and no need to modify. But as I continued to read the book, it said to change the oil in the compressor. And the pro's here also said other things like txv and some seals.