How to Repair a Zurn Wilkins 1-600XL Water Pressure Regulator

A water pressure regulator (pressure-reducing valve or PRV) is a control valve to reduce the water pressure to a safe level inside the home. If the pressure regulator valve doesn’t work well, too much water pressure can cause bath room, sink faucets or washing machine hose joints leak, because they are designed to work at a pressure of about 50psi.

A failed water pressure regulator valve should be replaced as soon as possible or that is what I want to say – Fix It as soon as possible.

Model: Zurn Wilkins 1-600XL

Problem: home water pressure creeps up to city’s street pressure when there is no water flow

This is one of the major brand and major model on the market. On hardware store’s website, check the reviews of this Model, there are several reviews report its leak pressure after 2 years or 3 years, that is just same as my problem. When there is no water flow, the home water pressure creeps up and eventually rises to city’s water pressure. It's not the first time I have uncounted this problem. I had this problem with my previous regulator. I replaced the second one with the same model because the same dimension was easier to install. But now, the same problem occurred with the second one. I don’t want to replace it third time. I decided to try and fix it. I thought if I can fix it myself, the thing will be under control, otherwise, I may need to replace a new regulator every couple of years.

In the next steps, I want to share how I fixed my water pressure regulator valve last week. Hope it can help someone who has the same valve problem.

This Regulator valve cost is $156.00. Fix it cost is only $2.57.

Step 1: Learning How a Regulator Works

A water pressure regulator controls water through a spring and diaphragm, which resistance and lowers the pressure to the safe level.

My regulator problem occurred in no flow. I want to learn how it works in no flow. I found a picture on the brand website finally.

As the picture shown, when there is no water flow, the home water pressure rises, counter-balancing the spring force, and the valve closes.

From this picture, It can be easily estimated - If the valve does not close properly, the home pressure will be equal city’s pressure. This is just my regulator problem.

Step 2: Open the Valve

Open the valve to check the interior.

There is no need to remove the valve from the water line. Since it was difficult to make photos of the valve which is in a corner, I took pictures with the old valve to show how to disassemble it.

Shut off water before starting disassembly and turn on a faucet to release line pressure.

Loosen main cap and remove counterclockwise.

Unscrew bell housing counterclockwise and remove spring, spring disc and friction ring.

Loosen plunger and remove counterclockwise.

Remove stem assembly from regulator.

I didn’t touch adjust bolt since it has nothing to do with the valve properly to close. The strainer has no relation with this too. Don’t need to do anything with the diaphragm keeping it on the stem.

Step 3: Inspect Rubber Parts

There are two rubber parts are important for closing the valve. One is the O-ring on the stem and anther one is seal ring on the plunger.

Remove and inspect the stem. Obviously the o-ring was worn out. Thinking about such a small o-ring has moved thousands of times over the bore wall in the past couple years, there is no surprising for it was worn out. The water pressure was leaked from the worn o-ring. It has to be replaced. The other rubber part - seal ring looks still ok and it can be used by turning over.

Step 4: Looking for Replacement Parts

To find a replacement o-ring is the key to repairing the regulator.

I have to say there is a repair kit online, but the cost almost as much as a new regulator. I don’t like it.

Checking on internet, I found this regulator parts list online. The o-ring part number is 113N. Checking on internet again, the o-ring 113 dimensions are 3/4” x 9/16” x 3/32”. About that “N”, I guess is “Neoprene”. Anyhow, with this information, I found a o-ring in hardware store, which is #11 o-ring 3/4” O.D. x 9/16” I.D. x 3/32” and it is same as the worn o-ring. The cost is $2.57 for 10-pack.

I can not find the seal ring either online or in store. But it is not worn too much and it can be used with back side by turning over.

Step 5: Reassemble the Regulator

Assemble stem unit using new o-ring

Turning over seal ring and screw plunger into stem unit, don’t forget the washer. A tip is screw little tightly since the water pressure can loosen the plunger. Also don’t over tighten plunger to avoid breaking the threaded end of the plunger.

Screw main cap, checking the gasket, if the gasket is broken, using plumber tape.

Put spring, spring disc and friction ring, then screw bell housing.

So far, this repair had typically completed. But for me it has not finished yet.

Step 6: My Special Problem

After replaced rubber parts, the regulator looks fine. But two hours later, I found that the pressure crept up again to the city’s pressure. It is a bit slower than before. But this means there is still leaking in somewhere.

I disassembled and reassembled the valve many times to check the rubber parts.

But in the end, I found that the problem was at the brass stem, not the rubber parts. There was a crack in brass of the stem which surface is contact with the o-ring. It likes a small hole between the stem and o-ring, leaking pressure to home side.