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Old 03-27-2011, 04:41 PM   #1
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Does this sound ok for a Local HVAC Tech Job?


So I'm helping my brother-in-law put in his system and I'm looking for a pro to help me set it up.. This the ad I'm thinking of placing.. am I asking for the right stuff?

The guy who did mine didn't flow nitro when brazing.. Is that something people feel strongly about?

-Jeff



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I'm looking for an HVAC pro to braze and setup a 3-ton Goodman AC unit with TXV at a single family house in Beaverton

All equipment will be connected and in place. Furnace is currently running.

Must braze 3 or 4 elbows (provided) on the suction line as well as standard liquid line brazes.
Must do a nitrogen flow while brazing to prevent buildup on the inside of the lines.
Must do a nitrogen pressure test and then pull a deep vacuum.
Must be familiar with the proper mounting of TXVs including the theory of operation of what they do and proper bulb placement.
Need to connect the TXV suction line pressure port to the internal supplied Shader valve present on cased Goodman coils.
Need to know how to properly charge the system for optimal AC performance.
Must know how to do a static pressure test and adjust dip switches on a Goodman Furnace.
Must perform a static pressure test.
Must provide all manifold gauge measurements, pressure measurements, Temperature drop measurements, and dip changes on a paper report (handwriting ok).

Goodman Equipment:
SSX160361A
GCVC950714CX
CAPF4860C6
VisonPro8000 T-Stat

Will pay time and materials at your going rate.

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Old 03-27-2011, 06:10 PM   #2
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Does this sound ok for a Local HVAC Tech Job?


In theory nitrogen is supposed to be flowed but VERY few guys do it or know how. Too much pressure and it blows out the weld. If the tech uses a hot enough acetylene torch and does his welds quickly excess carbon does not build up and cause a problem. (the purists will disagree but in reality nitrogen is not used as it slows down the job and cost $$ and piece work rate frowns on that). My installers don't use nitrogen and nobody I know of does. The problem lies when a tech uses not enough heat and a cheap small turbotorch on a bottle and takes his time and cooks the sheet out of the weld. Then it produces LOTS of carbon. The ad sounds good and paying by the hour should get you good results. Make sure he changes the oil in his vacuum pump first as that speeds up the deep vacuum a LOT.

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Old 03-27-2011, 06:50 PM   #3
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Does this sound ok for a Local HVAC Tech Job?


We use dry nitro as does every company in town that I've seen braizing in lines. Braizing rod flows at around 1500 degrees and copper oxidizes well under that,1000-1100 if I remember right.

Might want to specify 500 microns or lower instead of just a deep vacuum. Actually should be able to get the guy you want with a few phone calls instead of taking out an add.
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Old 03-27-2011, 07:06 PM   #4
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I have never found carbon plugging up an orifice and the drier catches it. Nitrogen is a good idea and if you can find a guy who uses it then go for it. If nobody does then make sure he uses a good acetylene torch or at least a turbotorch with a large 'B' tank acetlyene torch and not a small hand held job.
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Old 03-27-2011, 07:32 PM   #5
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Does this sound ok for a Local HVAC Tech Job?


I don't do a nitro trickle, I have tried it before and its very painstaking and you can rarely do all joints with it. I do it quick and then before I do the last connection on each side I blow the pipes out with nitrogen. If you blast nitrogen through the lines after braising I think it blows most of the flakes out.
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Old 03-27-2011, 07:55 PM   #6
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Does this sound ok for a Local HVAC Tech Job?


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I don't do a nitro trickle, I have tried it before and its very painstaking and you can rarely do all joints with it. I do it quick and then before I do the last connection on each side I blow the pipes out with nitrogen. If you blast nitrogen through the lines after braising I think it blows most of the flakes out.
Remove the schraders, and you can put the nitro in one schrader access and leave it come out the other. Very easy to do.
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Old 03-27-2011, 07:59 PM   #7
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Remove the schraders, and you can put the nitro in one schrader access and leave it come out the other. Very easy to do.

That is exactly how I do it BT. Of course when I brought that up over there I got my arse handed to me, I was so unprofessional and yadda yadda yadda, so I just say I flow nitrogen nowadays.
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Old 03-27-2011, 08:42 PM   #8
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I know, I use hard copper for exposed areas and braise large pieces together then install them, its pretty hard to trickle nitro that way. With a lineset its easy enough but linesets don't look as good exposed as hard copper does.
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Old 03-27-2011, 09:07 PM   #9
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I know, I use hard copper for exposed areas and braise large pieces together then install them, its pretty hard to trickle nitro that way. With a lineset its easy enough but linesets don't look as good exposed as hard copper does.
Because looking good is what counts, right? If you really want to do it the right way and use nitrogen while brazing, then you can simply dry fit a schraeder valve onto one end of the pipe to attach your hoses to; it doesn't matter that it's not an air tight connection. Most of the techs out my way don't use nitrogen, and most of the time it won't make a difference, but I always believed in a nitrogen purge.
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Old 03-27-2011, 09:44 PM   #10
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Because looking good is what counts, right? If you really want to do it the right way and use nitrogen while brazing, then you can simply dry fit a schraeder valve onto one end of the pipe to attach your hoses to; it doesn't matter that it's not an air tight connection. Most of the techs out my way don't use nitrogen, and most of the time it won't make a difference, but I always believed in a nitrogen purge.
The only purge I'm doing is a blast before the last connection, the filter dryer will do its job with whatever minuscule amount of flakes are left after that.
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Old 03-27-2011, 09:51 PM   #11
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I just braze it all together with both schraeders removed, if I'm brazing in a condenser and don't want to melt them, and put the low side shraeder in, pressure test the line set to about 150 psi with nitrogen, remove the high side hose which I've left the shraeder out of and blow the nitrogen charge. Any junk is sure to blow out. Put the other shraeder back in and then I pull the vacuum down to 500, 400 on long line and I'm done with the line set.
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Old 03-28-2011, 04:58 AM   #12
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I know, I use hard copper for exposed areas and braise large pieces together then install them, its pretty hard to trickle nitro that way. With a lineset its easy enough but linesets don't look as good exposed as hard copper does.
Wrap a good cloth rag around your hose. Insert in one end of the pipe and let the nitro flow through it.

Some guys have a cap that they have a schrader fittings tapped into and as early, they just dry fit it over the pipe.
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Old 03-28-2011, 05:01 AM   #13
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That is exactly how I do it BT. Of course when I brought that up over there I got my arse handed to me, I was so unprofessional and yadda yadda yadda, so I just say I flow nitrogen nowadays.
WHAT, you mean you don't use a 200 dollar liter gauge to regulate it.

It takes a thick skin over there. And you have to know how to keep your cool over there, when replying.
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Old 03-28-2011, 08:51 PM   #14
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Does this sound ok for a Local HVAC Tech Job?


The only time I flow nitrogen for A/C is when there are a lot of joints to be made. On the average split system you are only brazing 4-6 small joints, but on a commercial installs where you have many joints it is definitely a must. I have purged the lines with nitrogen in the past and then brazed them in without flowing through. All you are trying to do is get the oxygen out of the line so it doesn't carbonize on the inside.

Does it make a difference, try it out on your work bench with a few fittings and some scrap chunks of pipe, you will be amazed at the difference.
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Old 03-28-2011, 09:40 PM   #15
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Does this sound ok for a Local HVAC Tech Job?


I am not sure if you are going to get a real pro to answer your ad. The real pro will not cave in for those of your requiremnts even they know how to do that. most of them will do their own way and they will not let you tell them what to do. so you will end up with some one work behind the truck or some small one person company who does not have many business anyway. This does not mean you can not find a good pro to do your job, but be careful not to hire a jack head.

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