R410 Charge Question

[uglyduck]

Hi. I had a R410 HVAC system installed last summer. Everything was replaced (outside unit, furnace, lines, thermostat, etc). This season on the first hot day, I turned on my system and it wasn't cooling. I called the installer back and he said...

The R410 charge was slightly low causing the problem. I was concerned about a leak, but he mentioned that R410 systems work differently than older R22 that I'm used to. He said in older systems, if the charge was low, it would still cool, just not as well. He said in new R410 systems, there is no gray area and that if the charge is even slightly low, the system won't cool. It is not a gradual deterioration of cooling as the charge drops. He said that sometimes new systems "settle" and the charge might be a few ounces low and thus not cooling at all. He will be back in a few days to add more R410. He offered to show me the readings when he hooks up the equipment to charge to prove that only a little additional is needed. He also mentioned that he and I should have had a follow up check last summer where he would have caught the lower charge level and fixed it then. He promised years of worry free operation with a little added R410.

Problem is, I'm no HVAC guy, I won't know what I'm looking at if he shows me meters and guages. Common sense tells me to be worried about a leak. Also, the "on/off" property of colling with R410 chrage levels seems counter intuitive. So here I am asking for help from pros.

1) Is the information accurate about R410 being even slightly low will result in in no cooling? (i.e. no gradual decrease in cooling as charge drops)
2) Should I be more concerned about a leak in the system somewhere?

Thanks in advance.

[mark beiser]

He was blowing smoke up your hind end...

[uglyduck]

He was blowing smoke up your hind end...

Thanks Mark. I was just looking at some of your past posts and thought I hope this guy responds to my question.

So you're saying I got bad info AND I am right to be concerned about a leak?

[DLZ Dan]

I agree.

A slightly undercharged R-410a system acts like a slightly undercharged R-22 system.

[jpsmith1cm]

I agree with Mark.

Shyster salesmen and 'service' guys are everywhere and they don't know half of what they think they know

[Mr Bill]

He was blowing smoke up your hind end...

And not just up the hind end, but way up the hind end. :grin2:

[Cooked]

I've had plenty of R410 systems that were a few beans short of a barrel and they still blew cold air. I think this guy is full of doo doo. Did it cool okay last summer?

[Rcb2875]

The system will settle? No. The system will stabilize. That only takes about 15 minutes of run time under normal loads. He or the installer might not have added additional refrigerant to compensate for excessive line set length which would make it low on refrigerant. Some systems can be a little more sensitive to refrigerant balance but that isn't because it is 410a.

I would ask him to make a pass with a leak detector on the welds, valves, etc just to confirm there isn't a small leak in the leak prone areas from hasty installations.

[uglyduck]

Thanks all for confirming my suspicions.

Now, what should I have done to address the situation? In searching online, it looks like I may have a slow leak considering my system worked fine for one season and took all winter to possibly leak out the charge.

It seems there are several leak detection methods, but only 2 that seem to make any sense at this point. Electronic vs dye detection. I've read that electronic is time consuming and costly and may give false positives (perhaps not best for a slow leak). I've also read that dye (some kind of UV reacting dye) is cheaper and allows me to have a working system this season and for the leak to be found quickly next summer if it is indeed a slow leak.

Should I insist that a dye be added to the charge? How about a sealant? Should I insist on that?

Thanks in advance.

[2old2rock]

You learn something new every day. Thanks to your post, I now know the system charge needs to "settle" for a year before actually knowing if it's right.
Or, you may have a small leak, and he won't admit it.

[Rcb2875]

Thanks all for confirming my suspicions.

Now, what should I have done to address the situation? In searching online, it looks like I may have a slow leak considering my system worked fine for one season and took all winter to possibly leak out the charge.

It seems there are several leak detection methods, but only 2 that seem to make any sense at this point. Electronic vs dye detection. I've read that electronic is time consuming and costly and may give false positives (perhaps not best for a slow leak). I've also read that dye (some kind of UV reacting dye) is cheaper and allows me to have a working system this season and for the leak to be found quickly next summer if it is indeed a slow leak.

Should I insist that a dye be added to the charge? How about a sealant? Should I insist on that?

Thanks in advance.

DO NOT let anyone put a sealant in your new system! (or any system)

Electronic detection is fairly easy and quick in finding the more obvious leaks in places such as the welds that may have not bonded completely or valves and caps that aren't sealing. This also relies on how the tech maintains his equipment and the efficiency of that equipment. The UV dye makes it easier to visually spot where the leak is especially in the coils where a electronic detector isn't as efficient in the tight areas and when the leak is so small that some sensors can't detect it for varying reasons. I personally only use a dye after passing over the system with the electronic and nothing is found. I will always pass a detector on the problem spots before or after adding refrigerant as part of the service call to begin with at no additional charge. Using the electronic doesn't cost me or the customer any consumable product.