Question:
I am trying to repair an Ames 4” Model 2000SS. The check valves are very difficult to remove. Could the checks be cross threaded in the body?
Mark:
The check valves for the 2000SS are modular in design and are sometimes referred to as “cam checks.” Under normal circumstances, the cam checks should unthread easily from the body. The thread pattern for each cam check is very large, so it would be nearly impossible to cross thread into the body. First, let’s take a quick look at how the manufacturer instructs us to properly remove the checks. The first check needs to be removed before the second check can be removed. Ames recommends using a long screwdriver to help loosen each check valve. The screwdriver should be placed on the seat portion of the first check, either at the cam arm hinge point or the clapper hinge point. Pressure can be applied against the valve body for leverage or a hammer can be used to drive the check counterclockwise. (It is important to remember that if you plan on using the first check valve again, do not use the cam arm as a turning handle.) The second check, which has four protruding lugs or studs in the seat, is easier to remove by placing the screwdriver between two of these studs and applying pressure counterclockwise.
Doug:
In some situations, the cam checks are so difficult to remove that the screwdriver method may not work. This is the point where a “special tool” is needed to complete the repair. Some contractors have taken it upon themselves to construct their own removal tools. I’ve seen a few of them that are pretty clever works of art, to say the least. If you would prefer to purchase a tool, there are a couple of companies that offer after-market removal tools that seem to work really well.
Mark:
Be aware that there are certain situations when even the best-made tool will not budge the cam checks. The body of the Ames Silver Bullet series is made of stainless steel, which can flex or twist if torque is applied at the flange ends. This kind of stress can “egg shape” the stainless body. Even the slightest twist of the body will bind the threads of the cam checks and make removing them very difficult. So, what causes the body to flex? Many times this problem can arise if the piping was not aligned correctly during the initial installation of the assembly. It can also happen if the underground piping settles or moves for any reason. Of course, this causes a great deal of stress on the piping, fittings, and any fixture in the system, especially the stainless steel body of the assembly. valve poppet (aka, the spider assembly).
Doug:
This stress or torque on the body can vary greatly. Normally if the torque is slight, the old cam check can unscrew but the replacement check will not screw back into the body, thus giving the appearance of a defect with the threads. In some cases, the cam checks can unscrew from the body but cannot be removed through the top access hole because it is twisted into an “oblong” shape. In the worst cases, the checks will not turn at all. When this occurs, the only way to replace the cam checks is to relieve the stress or tension being placed on the assembly. The best remedy is to simply loosen the gate valve flange bolts on both sides of the assembly. Be sure not take the bolts completely out so that the bolt holes remain in alignment. The body should return to its original shape and allow you to replace the checks. Once the new checks are in place, tighten up the flange bolts.
