installers overcharging txv systems

[hvacmike85]

Air won't be in the liquid. Air being a vapor will only be in the top of the tank.

What if you used every drop in the tank the air/non condensibles won't escape?

[ironpit]

drops are liquid

[jamessnevets]

Regarding R-410A, I was once given a list of formulas for weighing-in additional charge when conditions were not optimal for adding charge by subcooling. The list was confiscated by a former employer of mine, but it had different weights correspondent to lineset diameters. The only one I remember b/c I use it frequently is for a 3/8x3/4 lineset, add .6 oz of R-410A per foot only if the lineset exceeds 15'. No need to measure subcooling with excessive heat conditions in the residence, and after returning to confirm, it has never failed me and I've used it since 2007. Something to check with your favorite supply house service guru. I'll see about getting the rest of it, if anyone is interested, since my current employer deals with the same supplier with the factory technician that originally gave me the list.

[TACKERDOWN]

1-800-406-2292 ReKlaim center

If you Google it it has a location finder just put in your zip code.

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[TACKERDOWN]

4) Additional charge for line sets above 15 feet. Values based on suction line as follows with 3/8" liquid line.(a) 3/4" = 0.6 oz. per additional foot.(b) 7/8" = 0.7 oz. per additional foot.(c) 1 1/8" = 0.8 oz. per additional foot.
This ones out of the install manual. I thought it was in all install manuals.
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[beenthere]

What if you used every drop in the tank the air/non condensibles won't escape?

Not if you don't draw out all of the vapor from the tank.

[dsprice]

These extreme conditions are what I do. Teach your subs what saturation is then instruct them to charge half the subcool. The Superheat should come in at the low to mid 20's with a split of 18 to 23. It works as long as airflow is right. Personally, I don't like for installers to do start UPS. Too many variables involved.

I understand the weigh in method, but never felt it was accurate. I can only guesstimate the length of the lineset.

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[coronachris0711]

I came across this problem today.... not the first time this has happend to me...

I changed out a indoor r410 a coil. Factory charge was 5 lbs 5 oz. Line set was about 40 feet. I charged in 6 lbs 5 oz. The system called for 14 degree subcooling.

Head was 350 PSI
Liquid line temp was 101
Indoor ambient 75
Supply air temp 59
Suction pressure 150
Outdoor temp 90

I needed liquid line to come down to 96 or so.... I tried adding 410 to pull down liquid line temp but everytime i did the liquid line temp would stay the same. Any one know what could cause this?

I guess my main question in regards to installers overcharging systems: What causes liquid line temp to stay the same or even increase after adding more 410?

[Toddbrewster]

It seems like goodman is not a good name on here, I am a goodman dealer, so far had good luck, just was curious as to what the general opinion of goodman is. I have done a lot of commercial and residential work, worked on a ton of different brands, I have some I do not care for, carrier/bryant both commercial and residential have terrible heat exchangers, dont particularly care for rheem ruud or lennox, although as I said I will work on any brand of equipment, like the challenge of learning as much as I possibly can, plus I am in the "Service" business cant be a good service tech if I cant fix something because of "name brand"! I do like trane, though they are a little more costly. Just was curious as to what it is about goodman that is disliked, maybe I need to sell a different brand. I have had units both commercial and residential from different manufactures, that have been both over and under charged from the factory, have not noticed a "rash" of any one brand being over or under charged, I check every system i install, or service and adjust the charge as needed, have had some that were fine with the factory charge with a lineset longer than 15' also have had some really over charged with a 15' line set. I also know several other companies/techs that install a system, flip the switch on and as long as the unit starts up they go no farther, no amp draw checks, no checks of gas pressure, temp. split heat or cool, no checking sh or sc on a/c or refrigeration systems, some may do the cold and sweaty test on the suction line, but most just stick out their hand for the money and take off.

[hvacmike85]

I came across this problem today.... not the first time this has happend to me...

I changed out a indoor r410 a coil. Factory charge was 5 lbs 5 oz. Line set was about 40 feet. I charged in 6 lbs 5 oz. The system called for 14 degree subcooling.

Head was 350 PSI
Liquid line temp was 101
Indoor ambient 75
Supply air temp 59
Suction pressure 150
Outdoor temp 90

I needed liquid line to come down to 96 or so.... I tried adding 410 to pull down liquid line temp but everytime i did the liquid line temp would stay the same. Any one know what could cause this?

I guess my main question in regards to installers overcharging systems: What causes liquid line temp to stay the same or even increase after adding more 410?

Alot of times I've noticed the liq line temp doesnt change much the liq press goes up which increases s/c that way, not sure why, but if your not getting s/c adding a ton of 410 will just result in an overcharge, you can only get so much s/c but it should let you go way past 14 if you wanted ( not that you do ) something might be wrong, always check s/h also, if your superheat is low you might have low airflow of stuck open txv, s/c is the charging method for txv systems but wont tell you all what is wrong

[sparky05]

Did you chance out the filter dryer? had a situation here on Friday where I could not get the Sub cooling correct on a unit, it was actually a negative 5 when it should have been a positive 12F, changed out the TXV and liquid line filter dryer, recharged the unit now everything is working correctly.

[sparky05]

On that unit, I got there and figured it was low on charge because it had had a leak, put a whole can of 410 into system and the S/C went from -5F to +4F it was when I looked at the name plate rating to see it should only take a little over 17 Lbs that I realized there was something drastically wrong so I recovered nearly 30 Lbs of 410A and weighed in the correct amount, but S/C only got to 2F.
I found that there was a 1F drop across the bi flow filter dryer, and I decided to change out the TXV the same time so I would not have to do it again just in case, it might have been stuck in full open position.

[hvacmike85]

On that unit, I got there and figured it was low on charge because it had had a leak, put a whole can of 410 into system and the S/C went from -5F to +4F it was when I looked at the name plate rating to see it should only take a little over 17 Lbs that I realized there was something drastically wrong so I recovered nearly 30 Lbs of 410A and weighed in the correct amount, but S/C only got to 2F.
I found that there was a 1F drop across the bi flow filter dryer, and I decided to change out the TXV the same time so I would not have to do it again just in case, it might have been stuck in full open position.

1 deg says it wasnt your filter dryer, but the txv, and I always do the dryer exp when theres a problem, manf says change dryer when system is opened for any reason but some people just dont wanna pay for a 20$ dryer, some H/O are just smarter than us I guess, anymore I just include it in the pric3 and dont tell em cause it will just raise questions