Heating, Air Conditioning, Fridge, HVAC/Cu A/C line set


QUESTION: I live in California. And you probably don't know the CA codes. But is there normally codes on the field assembly and brazing for Cu A/C line set? If so, where would be the best place to try to find them?   Thanks   Reg

ANSWER: Hi Reg,  In Missouri there are no codes that I can find. Try goggling CA "codes and regulation HVAC". If your interested in the proper installation of the line set, let me know and we can go though that.

Hope this helps.

---------- FOLLOW-UP ----------

QUESTION: Thank you Jim, Your answer was fast and efficient. I have not been able to find any codes or regulations in CA either. I don't think they exist.  I have seen HVAC pros assembling Cu line sets and they used the nitrogen purge system. ( I am a retired electrical and plumbing contractor.)  They had the nitrogen running through the line set as they assembled it. I didn't see any of this when they installed mine. The best I can remember, is that one guy held a nitrogen flow on the outside of the fitting while the other guy was brazing. I was told that was the way it was done. I don't think so. So if you could guide me to any relevant help I would appreciate it. Also, the line set is about 46 ft long and they used 10 long sweep 90's and 2 ls cu 45's. on a 7/8" O.D. line set. I believe they should have increased the size, but I don't know.   Thanks   Reg

Reg, The proper way is to flow nitrogen through the inside of the pipes as your brazing. Blowing nitrogen on the outside of the pipe will do nothing. What happens is when you braze without nitrogen the heat creates a black coating ( I can't think of the technical term)on the inside of the pipe which flakes off as the unit runs. They say it can get into the compressor and shorten the life of the compressor. Back in the day no one brazed with nitrogen and never had a problem.

As for the line set, go outside and pull the insulation back on the suction line, if there is a reducer on that line it is the wrong size line set. If the unit specs a 7/8" that is the correct size. For a long line set like yours all you need to do is add a little more refrigerant. The unit is precharged for a line set of 25 feet, in the specs it will tell you how much more you need per foot over 25 feet.

I have never installed a system with 10 90's in it. I only use a 90 if there is no other way. The only draw back to this is a slightly higher head pressure. I wouldn't worry to much about it.  

Heating, Air Conditioning, Fridge, HVAC

All Answers

Answers by Expert:

Ask Experts


Jim S.


I can answer questions on gas or electric furnaces, ac units and heat pumps. I don't work on boilers,chillers,or home appliances.


I have been in the HVAC trade for over 35 years. For the past 15 years I have owned my own business. I am semi-retired so I can answer questions in a timely manner.

I attended trade school for 5 years on weekends and evenings. This was very hard to do, but well worth it!

©2016 About.com. All rights reserved.