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Thread: Brazing Question

  1. #1
    DIY Junior Member Johnnyf0614's Avatar
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    Default Brazing Question

    Pardon my lack of knowledge... I have approximately a 13 year 3 ton York AC unit. I recently lost all of my R22 to a leak at the compressor. Repairman from one of the big HVAC companies by me quoted me $2000 to replace Compressor and add new R22. Or he can try and fix the leak. He was able to braze the leak, vacuumed, cleaned, and replaced with new R22. I realize this is basically a bandaid, and can't afford to replace the unit right now, but how long will the brazing typically hold? Is it similar to soldering copper and can hold for a bit? Or is it really just a bandaid that may get me through the summer? The cost for me to find the leak, braze/repair, and add new refrigerant came to under $800. Any guidance would be appreciated.

    I have a York H4DH036S06A model

  2. #2
    Nuclear Engineer nukeman's Avatar
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    Brazing is strong (stronger than solder). This is why HVAC systems are to be brazed vs. soldered. They typically run at higher pressures than say a water supply (R-410a can see pressures of 300+ psi). The other issue is vibration, etc. that could weaken the joint.

    How long it will last is anyone's guess. The repair may hold fine, but the question is that whatever caused it to leak may cause it to leak again somewhere else. If it leaks again, then it is just a matter of how large the leak is. If it is small, the system could be topped off every year or 2 (or whatever). It is expected that the price of R22 will increase over the years and you will reach a point where it will be better to replace vs. repair/refill.

  3. #3
    Retired Defense Industry Engineer jadnashua's Avatar
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    Both the refrigerant and possibly the oil may need to be replaced once there is a leak. WHen all the refrigerant leaks out, it may not be circulating the oil around either, and you could have some excessive wear. It last a very long time, it might die again shortly. Wouldn't replace it until it fails, but would start saving up for the eventuality.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  4. #4
    In the trades Dana's Avatar
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    R22 is a fairly environmentally damaging refrigerant from both a ozone layer and global warming potential (GWP) point of view- if the leak keeps recurring band-aiding it with frequent top-offs may be cost-effect from an out of pocket point of view for a short-termer, but replacing the unit with something that maintains it's hermetic seal is highly encouraged.

    In some countries it's legal to replace R22 with propane, and several R22 replacements out there are based on propane. But the oils typically used in R22 systems are miscible in liquid propane, so it's sort of like putting 5W oil in an engine designed for 20W- it won't crap out instantly, but it's not best practice. The flammability of propane has kept it from being a legal replacement in much of the first-world, even though propane is orders of magnitude more benign to the environment than R22 or R410A. In a hermetically sealed system it's not particularly dangerous, but I don't need to point out that yours has some leakage issues...

    R410A is far better refrigerant than R22 from the ozone point of view, but it too is an extremely potent greenhouse gas, and is likely to be phased out sometime in the next decade. Already HFC134a (the most common automotive AC refrigerant) was banned in EC, as of 1 January this year, and Honeywell is pushing their HFO-1234yf as a comparable but extremely low GWP refrigerant. Many of the European auto makers have settled on CO2 as the standard automotive AC refrigerant though, despite the extremely high operating pressures that require more expensive compressor technology. It's hard to predict at this point what will become the R410A replacement for the residential AC market, but if you're out & out replacing the R22 based system, it might be worth looking into it a bit closer, even if R410A is still the dominant refrigerant, lest you be looking at yet another orphaned-refrigerant system 15 years hence.

    Hopefully the brazing job will hold up, and you get another decade or so of service out of it.

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