Test Plugs for the Water Test
It is good practice to test the shower pan's hot mop liner before putting up any tile backer or laying the deck mud for the tile base. This will give you peace of mind that you are building on a non-leaking shower pan. In addition, if there is a leak after it has been worked on, it can be difficult to pinpoint the cause and consequently the liability.
To give the hot mop time to cool, we do not leave it filled with water. A couple hours of cooling is enough before filling the pan with water.
If you will be filling the pan with water it is best to put a test plug in the drain pipe before we come out to hot mop. However, make sure the test plug fits through the top of the strainer part of the drain. Otherwise, it could get stuck in the drain after the hot mop. It is best to have whomever installs the drain to also install the test plug.
The test plug must be set into the pipe below the drain assembly. This ensures that drain assembly is tested along with the hot mop. Most shower pan leaks are a result of a drain assembly failure not the hot mop.
Here is a picture of a pneumatic "ball and chain" or "weenie" test plug. These test plugs drop into the pipe and are pumped with air so that they expand within the pipe.
Here is a picture of a compression wing-nut style test plug.
These test plugs have a wing nut that when tightened expands the plug within the pipe. They are also more affordable than the pneumatic plug. However, these plugs are much wider and sometimes don't fit through the top of adjustable drains. If not checked to fit before installing and hot mopping they will get stuck in the drain assembly. This might require us to come back to do a patch and remop which we have to charge for.
No matter what type of plug you'll need it is always a good idea to test the shower pan before laying tile.
If you have any questions, please feel to contact us anytime!