When brazing a service valve, make sure the valve is mid-seated. The heat generated from brazing a fully front-seated or back-seated valve can cause the button of the valve stem (inside the valve) to “weld” to the seating area on the inside of the valve body.
A technique called wet-ragging can help in the process. Soak a rag in cold water and wrap it around the service valve before brazing. Make sure the water does not enter the valve.
When opening a service valve, make sure the valve is secure (in a vice or bolted down) before attempting to open the packing nut or valve stem. Verify whether the valve employs a packing gland nut.
The packing nut helps to ensure a leak-free seal. It typically is brass and is found at the base of the valve stem. It must be loosened by a quarter to a full turn before opening the valve. Make sure to tighten the nut when you are finished manipulating the valve stem.
You will only be able to open a service valve with the appropriately sized service valve wrench. Do not attempt to open a service valve with an adjustable wrench – you may round the valve stem edges and the valve will be useless.
If alleles fails and the stem appears to be stuck, lightly tap the end of the valve stem with a hammer and the valve should open. If the packing gland nut is not loosened, the valve could be damaged.
Source: Emerson Climate Technologies contractor tip card
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