HVAC tech on the

[tb1472000]

I like the way this site is so direct in responding. While I’m a homeowner, I’m trying to distinguish the great installers from the others. Your help to educate us is appreciated.

I'm a homeowner that hired a local company to install a new A/C. This was a Trane 5 ton unit replacing a 9 year old American Standard. Same company serviced the American Standard. The tech had a difficult time brazing a leak free joint at the evaporator. Not sure of the line sizes, but the evaporator tube was something like 1.25 inches and the line set was something around 7/8 inches. The tech didn’t use a reducer coupler, but rather just used Channel Locks to crimp the large line to fit around the smaller and then attempted several times to braze the joint. He finally got it to be leak free. The odd thing was the original American Standard coil was connected the same way. However, it wasn’t installed by the same company. Is this a common way to complete this joint, or are these Wall of Shame candidates?

The tech did purge lines with nitrogen. The previous system had a leak in the system and that contributed to the system being replaced. The line set wasn’t replaced. Had three estimates and all said the lines didn’t need to be replaced. Is that what you would have done? I’m sure there are many other variables, but approximately how long should he have ran the vacuum pump to clear the line set prior to charging the system after he installed the new condenser and evaporator?

Thanks,
Bruce

[Senior Tech]

Originally posted by tb1472000
I like the way this site is so direct in responding. While I’m a homeowner, I’m trying to distinguish the great installers from the others. Your help to educate us is appreciated.

I'm a homeowner that hired a local company to install a new A/C. This was a Trane 5 ton unit replacing a 9 year old American Standard. Same company serviced the American Standard. The tech had a difficult time brazing a leak free joint at the evaporator. Not sure of the line sizes, but the evaporator tube was something like 1.25 inches and the line set was something around 7/8 inches. The tech didn’t use a reducer coupler, but rather just used Channel Locks to crimp the large line to fit around the smaller and then attempted several times to braze the joint. He finally got it to be leak free. The odd thing was the original American Standard coil was connected the same way. However, it wasn’t installed by the same company. Is this a common way to complete this joint, or are these Wall of Shame candidates?

The tech did purge lines with nitrogen. The previous system had a leak in the system and that contributed to the system being replaced. The line set wasn’t replaced. Had three estimates and all said the lines didn’t need to be replaced. Is that what you would have done? I’m sure there are many other variables, but approximately how long should he have ran the vacuum pump to clear the line set prior to charging the system after he installed the new condenser and evaporator?

Thanks,
Bruce

Although I prefer reducing couplings for neat appearance it is and has been common practice for years to pinch copper and braze. No line set? Let's hope the leak wasn't in it although if the right equipment was used a leak would have been noticed. As far as vacuum...no specific amount of time, rather a vacuum should be measured in microns with a quality micron guage, down to 500 microns, could take minutes or hours depending on as you put it "variables".

[t527ed]

would prefer to use reducing fitting. would NEVER reuse line set unless old one could not be replaced. what ever was in old system is now instantly contaminating new system.

[Jultzya]

New line set, micron gauge for vacuum monitoring, and would have run the appropriate line set size for reliability and efficiency!

[core]

I find it amazing how many HOMEOWNERS come on this site and ask these questions.

I will assume that you will start asking the tech. that is doing the work to see his micron gauge or ask him "Why didn't you change the line set....arn't you suppose to??

Let me ask you this SIR.

"If it took me 10 Hours to pull your system down to 1000 Microns (which by the way is my perferred evacuation) would you be willing to pay $95.00 Hr for this job?????

Would you pay me $95.00 Hr. to watch a Micron gauge??????

Can any homeowner answer this question??

[tb1472000]

Thanks for the quick replies, now for a follow-on question. Isn't a micron a thousandth of something? I’ve seen vacuum pumps for woodworking vacuum clamping rated in capacities such as 25 inches. What is the micron rating in the A/C vacuum pump?

Thanks,
Bruce

[Jultzya]

Switched to homeowner mode... for a sec.

$95 an hour!

I work at a factory and make $15! You are charging WAY to much. You are a crook!

Ok, I'm back to tech mode.

[Senior Tech]

Micron...one millionth of a meter...core...valium...the wonder drug.

[Jultzya]

1" = 25,400 microns. (system should hold under 500)

For more infomation on vacuuming priciples go here.

A lot of valuable information is at the above link!

[Chill]

How is the system running? Give us a little back ground here.

[tb1472000]

Core, you seem to be way too sensitive. I've always been interested in anything to do with construction and learning new things. I was curious what others in the industry would have recommended. I thought this site was created to try to educate everyone. Sorry if I offended you. My goal is simply to understand HVAC technology better.

The answer to your question about watching a vacuum gauge is: I contracted with a company to install a new Trane A/C. I believe that I paid to get the system installed properly. If installed properly means someone has to watch a vacuum gauge, then yes, I agreed to pay that price.

Again Core, I’m sorry if I offended you.

Thanks,
Bruce

[Jultzya]

I'm curious as if there was a load calc preformed?

[tb1472000]

Chill, the system is running just fine and keeping the house nice and cool in our record heat summer. The old system developed a leak in the evaporator coil and the compressor stopped running. All three companies indicated replacing everything but the line set on a nine year old system was the proper way to go. That sounded reasonable, so I contracted with the one that had done other work for me in the past. That was the middle price estimate. The lowest price didn’t spec a Trane, so being lower may not have meant much.

Thanks,
Bruce

[tb1472000]

Jultzya, No, none of the companies did a load calc. They all asked if the old system was providing satisfactory comfort. Since it was, they seemed to feel that they didn’t need to do it. Is a load calc something that you would expect to be done on every replacement system?

Thanks,
Bruce

[Chill]

Sounds like a good install to me. You won't be needing to replace for a long time. All that you learn now will be forgotten, by then. Have it serviced every year and you will catch any problems before they cause any damage.

[Jultzya]

Yes, it should be... who knows whether the old equipment was sized to your home?

It may have been preformed then, it may not have, or it could have been figured wrong at that time.

When my reputation is on the line... I trust NOBODY!

You can check it by clicking the 'red dot' at the top-right of this page.

[dpatty]

I personally recommend a load calc on all jobs but if the customer just wants the system replaced with the same I for go it. I do also explain the benifits of higher end stuff that will save you money for years after I've done my job and gone. If making a change like that then I require a load calc. As far as your question of replacing the line set, purely a judgement call.

[beenthere]

Originally posted by core


"If it took me 10 Hours to pull your system down to 1000 Microns (which by the way is my perferred evacuation) would you be willing to pay $95.00 Hr for this job?????

You should charge more, and pull a real vacuum, 1000 microns isn't deep enough.

[badbillr]

i also prefer to replace line-set when possible. sometimes replacing the line-set is just not possible to go back in the same space, not w/o thrashing the something.

since the system was replaced due to leaking equipment, there really shouldn't be any contaminants in the line-set. may be a little residual oil that was trapped in a low spot. i am usually more concerned with corrosion from years of service, especially the suction line which is exposed to water constantly from condensation. also possible kinks in the line-set from when it was originally installed. they were splicing 7/8" soft copper, pretty easy to deform that stuff when trying to bend it. i find more kinks in the suction line where the line-set enters the attic space via gable end or roof eave. i use a ratcheting hand bender to make those turns. only a few more minutes to braze in an elbow then armorflex, glue & tape.