p-trap link??

[primmers]

i did a search and came up with a ton of posts but nothing in them were about p-traps..

[k-fridge]

What do you want to know?

[primmers]

ive seen them at the top of a vertical run..as well as the bottom

i just did a walk in refer, i stuck one at the bottom of the run at the evaporator, went up and hung a 90* to the condensing unit (which is on top of the walk in)..

was just wondering about that u/p trap at the top..

[oogene]

check the pro training area for a download from dupont about refrigerant piping handbook, might find something there.

[smilies]

Suction risers? Heatcraft has pdf on it

[icemeister]

The trap at the top of a riser is known as an inverted trap and is used primarily to prevent reverse drainage of oil (or liquid refrigerant) back down the riser.

In the case of a walk-in with a single evaporator and the horizontal run is properly pitched in the direction of flow, the inverted trap is not necessary. If there are multiple evaporators that have branch suction lines tied to a single horizontal run each branch must enter the main run from the top, so an inverted trap is required if the main is above the evaporators.

There are many additional instances where you should apply an inverted trap like in double risers and at the top of discharge risers, but this example is likely the one you'll run into most often. Again, they're used essentially to prevent reverse drainage...whereever it might occur in a system.