Do Schrader valves wear out in central ac units, causing Freon to leak out, and no cooling.
Purchased home with Central A/C unit 1.5 tons. Don't know service background.
It is 17 years old. No cooing at end of summer in September. Several months later,
HVAC tech tested system says there is a leak, everything else OK. To find leak must do Nitrogen test. Would checking the Schrader valves be first step.

Thanks for response.

 

Schrader valves can leak but normally they're covered with a service cap that keeps them sealed.

On a 17 year old system I'd expect to find the evaporator coil rusted and possibly corroded thru. The evaporator is typically where the problem is found. Can you get to the coil in your air handler ?

 

There are two Schrader valves on the outside unit. When I depressed the needle (similar to a bicycle tire valve), a slight hiss with air was present. There must be a slight pressure at ground level. I did not fully let air out. The HVAC tech had done a pressure test by running unit when he said there was a leak.
The air handler is in the attic, which is more like a crawl space meant for the A/C unit. There is no walk up steps, and I would need a step ladder to go up. There is also blanket insulation, that may need to be covered. If the coil has leaks, the Tech said he could braze to seal up. I can't agree to this. Can the coil itself be replaced or does the entire Air Handler need replacement ?
Thanks for comments.

 

Hi, I would say that a 17 year old system has had a good life and should probably be replaced, I think you will be hard pressed to find someone that will just replace the Evap.
Geo

 

If I need to replace the entire Air Handler, can I continue to use the condensing unit which is a R-22. I would prefer an alternative refrigerant because it is less cost. My question is: would a new Air Handler (or new coil) with new alternative refrigerant work with the old condenser unit ?

 

No. At the present time due to the extremely high cost of R-22...... you'd want to retire the condenser. You'd actually come out ahead in replacing the condenser and coil together and eliminate the cost of the R-22.

 

Am I correct to understand: the R-22 condenser cannot be retrofitted to run on newer refrigerants, as can the coil or air handler ?
Thanks

 

That is correct. You can still buy R-22 coils on a repair basis. It's the cost of the R-22 that is prohibitive.

 

There are drop in replacement refrigerants. But at that age if something major needs replaced, you’ll want to replace everything with AHRI matched R-410A equipment.
There is no reason to piecemeal your current system together.