Author Topic: Standards for Brazing  (Read 2114 times)

Offline walker

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Standards for Brazing
« on: August 17, 2017, 03:58:33 PM »
Are there any requirements for the material used for brazing?

I've been seeing some guys using soft solder to do some joints.

I've personally only ever used 5% & 15% silver solder rods.

I could see the benefits on using soft solder to do sensitive components like txv's.

I do know that some manufacturers do specify to braze only and to not use any flux.  But some manufacturers just specify to use what ever local codes dictate.


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Re: Standards for Brazing
« Reply #1 on: August 17, 2017, 05:07:17 PM »
From the B52 Mechanical Refrigeration Code,

Quote
Brazed joint — a gas-tight joint obtained by joining metal parts with alloys that melt at temperatures higher than 427C (800F) but lower than the melting temperatures of the joined parts.

Soldered joint — a gas-tight joint formed by joining metal parts with alloys that melt at temperatures above 204C (400F) but not exceeding 427C (800F).

Clause 5.7.2.4 - The joints on copper tubing used in refrigeration systems shall be brazed. Soldered joints shall not be used in such refrigeration systems.

I also attached a couple of pages from the Lennox 13ACX installation manual.

Offline walker

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Re: Standards for Brazing
« Reply #2 on: August 17, 2017, 05:54:28 PM »
Thanks for pointed that out.  I was looking in the C273.5-11 and couldn't find anything specific.

What is the scope of the B52 Mechanical Refrigeration Code, does that include residential air conditioning?

Offline walker

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Re: Standards for Brazing
« Reply #3 on: August 17, 2017, 05:58:58 PM »
From the B52 Mechanical Refrigeration Code,

Quote
Brazed joint — a gas-tight joint obtained by joining metal parts with alloys that melt at temperatures higher than 427C (800F) but lower than the melting temperatures of the joined parts.

Soldered joint — a gas-tight joint formed by joining metal parts with alloys that melt at temperatures above 204C (400F) but not exceeding 427C (800F).

Clause 5.7.2.4 - The joints on copper tubing used in refrigeration systems shall be brazed. Soldered joints shall not be used in such refrigeration systems.

I also attached a couple of pages from the Lennox 13ACX installation manual.

Also do you have a copy of the B52 codebook?

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Re: Standards for Brazing
« Reply #4 on: August 17, 2017, 06:29:01 PM »
You bring up a good point.  I found this in the B52.

Quote
1.2.3
This Standard does not apply to the following:
(a) the use of water or air as a refrigerant;
(b) bulk-storage gas tanks not permanently connected to a refrigeration system;
(c) refrigeration systems installed on railroad cars, motor vehicles, motor-drawn vehicles, aircraft, or
ships; and
(d) refrigeration systems used for air conditioning in private residences.

The TSSA has guidelines but they don't apply to us if we're working on AC's 5 ton or smaller.

http://www.hvactechgroup.com/hvacforum/index.php?topic=1778.msg5066#msg5066

I'm not near a PC to check the Refrigeration textbook.


Offline walker

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Re: Standards for Brazing
« Reply #5 on: August 17, 2017, 07:48:32 PM »
You bring up a good point.  I found this in the B52.

Quote
1.2.3
This Standard does not apply to the following:
(a) the use of water or air as a refrigerant;
(b) bulk-storage gas tanks not permanently connected to a refrigeration system;
(c) refrigeration systems installed on railroad cars, motor vehicles, motor-drawn vehicles, aircraft, or
ships; and
(d) refrigeration systems used for air conditioning in private residences.

The TSSA has guidelines but they don't apply to us if we're working on AC's 5 ton or smaller.

http://www.hvactechgroup.com/hvacforum/index.php?topic=1778.msg5066#msg5066

I'm not near a PC to check the Refrigeration textbook.

So basically there is no requirements for 5 ton or smaller, just follow manufacturers recommendation.

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Re: Standards for Brazing
« Reply #6 on: August 18, 2017, 05:29:18 AM »
I found this in the Refrigeration and Air Conditioning Technology 7th.

Quote
Soldering is a process that joins piping and tubing to fittings.  It is used primarily in plumbing and heating systems utilizing copper and brass piping and fittings.

Brazing is similar to soldering but requires higher temperatures.  Often called silver brazing or hard soldering, it is used to join tubing and piping in air-conditioning and refrigeration systems.

I would say we shouldn't solder refrigeration tubing.