Question:
I have a 3” Watts Model 009 that needs to be serviced. I want to replace the check valve discs and relief valve rubber goods. Can you go over the repair procedures for this assembly?
Mark:
The 3” Watts Model 009 is a reduced pressure principle assembly. Production of the original unit began in 1989 and a lead-free version (LF009) was introduced in 2010. The leaded bronze parts were replaced with plastic or stainless-steel materials, but the repair procedures and replacement parts are the same for both assemblies. There are no special tools needed to make this repair. This unit has a single access cover that is o-ring sealed and is secured by hex head bolts. The sensing line is external and located with the #2 test cock. The brass sensing tube is secured by a retaining screw that must be removed first.
Doug:
There is a slight spring load on the cover, so make sure to hold firmly while removing the bolts. When the cover is lifted off, the relief valve stem assembly and RV spring will be free to remove from the body. The check valve modules are sealed by an o-ring and secured by a retainer. The stainless-steel retainer should slide straight up and out of the body. To remove the first check module, simply grasp the spring retainer (cage) and pull straight out of the body. To remove the second check module, use a flat head screw driver to help pry it straight out of the body.
Mark:
To disassemble the check modules, the plastic retainer (cage) must be removed. Note: The check spring is retained so there should be no spring load or disc replacement to deal with during disassembly. The retainer cage is attached to the seat with a bayonet locking system. Hold the cage firmly in one hand and push the seat inward with the other hand. Rotate counter-clockwise approximately ¼ turn. Once it is unlocked, then the spring assembly and seat are free. To replace the check disc, simply remove the stainless-steel retaining nut. Reassembly and installation of the checks will be in reverse order. Remember when replacing the stainless-steel retainer that it must slide into place easily. If it does not, then the check modules are not fully seated into the body.
Doug:
To replace the relief valve rubber parts, the stem must be disassembled. The RV molded disc is located on the lower stem and is secured by a retaining nut. Be careful not to damage the stem guide when removing the retaining nut. Be aware of the stem o-ring that is located behind the disc. To replace the diaphragm, simply unscrew the stem cap from the upper stem. The diaphragm is positioned between two stainless plates. It is very important that they are in the correct position during reassembly. You will notice that the top plate is concave and must face up toward the stem cap. The bottom plate is flat and the lip must face down toward the lower stem.
