I think we may finally be seeing end of life on our 12-year old unit. Any feedback on units with new R-32 refrigerant. When I looked at proposals last fall, I talked to 4-5 different HVAC contractors in BCS and saw a 50/50 split on them recommending R-410a (at the time) or just moving to the new.

It makes most sense to me that 32 is the way to go since you hope that you get another 8-12 years out of a new unit and any 410a available at that time is going to be significantly higher in cost.

Mainly curious if anyone in the business has any insight on how things are going now that they've started the phase-out.

Only Daikin/Goodman/Amana are using R32 to my knowledge, everyone else went with R454B.

Currently we are dealing with a shortage of refrigerant in the market but we have heard that it should be back to normal by mid summer. What I interpret that to mean is there's a boat in the ocean somewhere full of tanks of refrigerant that finally got clearance to go to port.

I only install Ruud equipment and we've installed a fair amount of the new systems already and as of today we've only had one issue and that was a system that was not fully charged from factory. I'm not sure of the long term quality of the new refrigerant but we were told from day 1 that it's only a 10year stop gap to get us to the next refrigerant, whatever that means.

The only other thing worth noting is that my company is highly encouraging replacing the refrigerant line set if the house is older due to issues we've had with copper lines leaking. We've had more than a handful of older homes where the system will hold nitrogen pressure but will leak refrigerant through the walls of the copper tubing.

Whatever you do, make sure you register your warranty with the manufacturer if your contractor doesn't and save the certificate that gets generated. You will eventually need it.

Hope that gives you some insight, if you've got any other questions feel free to ask.

Caleb

call Jim Wolf (owner of Wise Guys AC) class of 88. He has helped a lot of Aggies on projects like yours. 832-347-0807 .

TruService HVAC said:

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We've had more than a handful of older homes where the system will hold nitrogen pressure but will leak refrigerant through the walls of the copper tubing.

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Wow. That's disconcerting.

What do you think is causing that? I realize we've always had issues with the copper in an evaporator coil due to several things (moisture / dissimilar metals / etc), but hearing about it in a line set sucks.

Are the leaks large enough that they'll blow bubbles, or are you seeing it with electronic detectors?

To clarify, I've only seen it with R410a to date.

The only thing I can think of is the molecule size of nitrogen vs r410a. I failed chemistry twice so I'm not even going to try and look it up but that is the only thing I can think of.

We had one that would hold 250psi nitrogen for days and after you charged it and left three or four days later it would lose enough charge to not cool but not freeze. We spent the better part of two weeks chasing it and thankfully the client had a guest house to stay in and was willing to let us fight it until we won.

Bald Eagle said:

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call Jim Wolf (owner of Wise Guys AC) class of 88. He has helped a lot of Aggies on projects like yours. 832-347-0807 .

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Avoid a Daiken/Goodman system with all your heart. I had the guys above install a Goodman unit it and has been nothing but trouble. According to my current company, the system was poorly installed and they hate working on those units. In my opinion, it's a piece of *****

Thanks a bunch for the reply on the line set leaks you experienced.

Heck, I've been nitrogen testing at 200 psi and figured it was 'good' if it all held. You're going one better than I have by testing at 250 psi and still had the problem.

Now I'll add this to my list of things to worry about. It's always 'something', isn't it?

FWIW, I'm not in the business like you are. I just picked up the skills (and the tools) while doing industrial maintenance in a manufacturing plant where you were expected to fix anything and everything and calling an outside contractor in for help was discouraged.

TruService HVAC said:

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To clarify, I've only seen it with R410a to date.

The only thing I can think of is the molecule size of nitrogen vs r410a. I failed chemistry twice so I'm not even going to try and look it up but that is the only thing I can think of.

We had one that would hold 250psi nitrogen for days and after you charged it and left three or four days later it would lose enough charge to not cool but not freeze. We spent the better part of two weeks chasing it and thankfully the client had a guest house to stay in and was willing to let us fight it until we won.

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Nitrogen is smaller. R410a is a 50/50 mixture of CH2F2 (difluoromethane) and CHF2CF3 (pentafluoroethane).

MW of Nitrogen = 28.014
MW DiFluor = 52.024
MW Penta = 120.02

Now, one of the components could leak out and that would do two things: lower pressure and upset the balance of gas composition. Since you don't have the same composition (50/50 is now 25/75 or something), the thermo properties aren't the same. It doesn't condense at the same pressures, it doesn't vaporize at the same temperatures, etc. so the system won't 'work' the same.

A partial thought could be the presense of oil. N2 won't dissolve in the oils, which can dissolve R-410a, which leads to it leaking out vs. N2 staying put. This is just my SWAG; I cannot point to anything that would say 'yes'.

~egon