question about refrigerant hoses

[dave1234]

Hello. This may be a dumb question but I feel its kind of important when working with small systems under a lb of charge or so. Just how much does the average refrigerant gage line hose hold? "They say" (whoever they are) "a couple oz and that is obviously the case, but Ive never seen it an a new set of hoses. Say your average 4, 5, or 6 ft hose. Just wondering. Its nice to kind of know when charging a little cap tube system that only holds 6-8 oz and the gages have no shut off or check valve. Thanks.

[icemeister]

Here's a link to the Ritchie Yellow Jacket web page for hoses:
http://www.yellowjacket.com/content/catalogs/hvac/04Hoses.pdf

Check out p.25. It gives you the weight of liquid per foot of hose.

If you do what I do though, it doesn't matter what the hose holds. (Note however I use the Yellow Jacket hoses with low loss connectors w/ check valves.):

1. Pull a proper vacuum using both the high and low side ports.

2. Disconnect the vacuum pump and attach the yellow hose to your refrigerant cylinder in the upright position.

3. Open the cylinder valve and then briefly crack the hose connection at the manifold set to purge and pressurize the hose.

4. Set the cylinder on your scale in the inverted position and zero it out.

5. Open the high side manifold valve to charge liquid into the system, closing it when the desired weight is reached.

6. Start the system and slowly meter the remaining liquid in the yellow hose to the low side.

7. Disconnect the yellow hose from the cylinder.

8. Disconnect the red hose from the high side port and slowly meter the liquid in that hose to the low side.

9. Disconnect the blue hose from the low side and you're done.

The weight of the small amount of refrigerant vapor left in the hoses is insignificant, so this way you get all the refrigerant you weighed into the system without knowing how much was actually in the hoses.