Question on fixing slow evaporator coil leaks (non DIY)

[jack black]

Hi,
I noticed my 13 year old Lennox heat pump cooling less this summer despite my regular maintenance (filters, cleaning of both coils, etc). I asked a local HVAC firm (highly recommended by my coworkers) to come over and see it. The added 2 lbs of R22 and diagnosed evaporator leak (I paid the service charge $$$). I was left with estimates for new system or new air handler. Both $$$$. They declined to repair the coil leak nor they told me how fast the leak is.

I bought a freon leak detector on ebay ($$) and found 2 slow leaks near TXV (took a while to find it and no bubbles with regular soap). See arrows and circles on the images.




Is this something reparable, or do I really need the $$$$ new unit?

How do I convince HVAC contractor to repair rather than replace? Everyone seem to only replace things these days.

I'm concerned that the new units are full of parts made in China and not as reliable as old ones. Case in point: I replaced only 2 contactors and one capacitor in 2 Lennox heat pumps in 13 years, the brand new contactor (made in china) failed after only 6 months (coil burned and shorted)!
I know that the new units are more efficient, but its only $230 difference a year for me according to my calculation.

Thanks!

[Joker]

If they where leaking there it would not cool almost instantly!

2lbs is nothing if it last all year.

The reason no one likes to fix coils is that they tend to fall apart as you solder them. Which cause a minor problem to turn into a much much bigger problem.

A/c parts are made in the good ole USA by illegal aliens. Whats the problem?

[jack black]

If they where leaking there it would not cool almost instantly!

What do you mean? The system seems to work fine for 3 weeks now. Are you saying there cannot be slow leaks from these spots (TXV and that blind line)? I could only detect them by nearly touching the sensor to the metal and only on highest sensitivity. But it was very repeatable. I tested like 10 times to make sure it was a leak.

[hvacrmedic]

You didn't lose refrigerant from the system from those points.

[jack black]

OK, there seems to be consensus on this. May I know why I cannot lose the charge from those spots? Are you saying there must be additional leak and what I detected was false positive?

[Joker]

OK, there seems to be consensus on this. May I know why I cannot lose the charge from those spots? Are you saying there must be additional leak and what I detected was false positive?

That is a gas filled bulb used to regulate the TXV. If it where to leak it would lose the gas charge and the TXV which meters the freon through the coil would cause it to stop metering freon and the system would stop cooling.

[jack black]

OK, makes sense and shows how little I know. I will go back and play some more with the sensor.

[Joker]

OK, makes sense and shows how little I know. I will go back and play some more with the sensor.

Most leaks are found at a solder joint. I would start at the small copper first since they tend to vibrate more.

It could be as simple as leaky schrader valves outside.

Oh well have fun with your new toy.