Shut off the inlet water pressure, remove the strainer plug, then take out the strainer and clean it, as the Watts sheet for the LF25AUB-Z3 says. Depressurize the valve first, and open the inlet slowly afterward. Watts also says the valve must be tested at least once a year.
How do you clean the strainer?
Watts's maintenance instructions for the strainer are short: shut off the inlet water pressure, remove the strainer plug (part 2 on the parts drawing), then remove and clean the strainer (part 77). Here is that sequence with the sheet's other notes folded in.
- 1Shut off the inlet. Close the valve that feeds the regulator from the supply side. The sheet's typical drawing shows shutoff valves on both sides of the regulator, which is what makes this step simple.
- 2Depressurize the valve. The sheet carries the warning to depressurize the valve before servicing, so do not open anything while it is under pressure.
- 3Remove the strainer plug. This is the plug that Watts labels part 2. It has a gasket, part 104, which is a rubber part.
- 4Take out the strainer. Pull the strainer (part 77) and clean it.
- 5Reassemble. Put the strainer and plug back, with the gasket in place.
- 6Open the inlet slowly. Watts's maintenance notes end with the line to open the inlet water supply slowly.
- 7Check for leaks and read the gauge. The sheet says to inspect for leaks after start-up, and to use a pressure gauge to verify the setting any time a reducing valve is adjusted.
### What if the gasket looks worn?
The sheet marks the strainer plug gasket as a rubber part and lists it in the repair kit. The kit for the Series LF25AUB-Z3 includes all the rubber parts shown on the drawing, which are the diaphragm, the O-ring, the seat, the disc, the strainer plug gasket and the bottom plug gasket. Watts sells kits under the number LF25AUB-RK in sizes from 1/2-inch to 2-inch. When ordering, Watts says to specify the ordering code, the size of the valve, the type number, and the model shown on the nameplate.
### Why is opening the inlet slowly on the list?
The sheet does not give a reason. It simply ends its maintenance notes with the instruction to open the inlet water supply slowly, so treat it as a rule and follow it.
How often should the strainer be cleaned?
Watts's sheet has a heading, "Need for Periodic Inspection/Maintenance." It says the product must be tested periodically in compliance with local codes, but at least once per year or more as service conditions warrant. It adds that corrosive water conditions, and unauthorized adjustments or repair, could render the product ineffective for the service intended. It also says regular checking and cleaning of the product's internal components helps assure maximum life and proper product function.
The yearly minimum in that passage is for testing. For cleaning, the sheet gives no set interval. It ties the work to regular checking and cleaning of the internal components, and to the symptoms below.
### What symptoms mean it is time?
Watts says maintenance may be required when the water downstream of the valve shows one or more of these: excessive water pressure, insufficient water pressure or flow, or inconsistent water pressure. Its troubleshooting list for high pressure with no flow also names dirt or debris on the seat as a cause, alongside thermal expansion and pressure creep. Our page on why pressure rises after a Watts pressure reducing valve explains each cause.
The City of Phoenix lists other reasons for low pressure that have nothing to do with the regulator. They include a buildup of mineral deposits in galvanized plumbing, a water softener in need of maintenance, a partially closed house valve, and debris in aerator screens on bath and kitchen sinks. Rule those out too. A clogged strainer is one cause among several, and cleaning it will not fix a closed valve.
What should you know before you open the valve?
### What does Watts warn about?
Beyond the depressurize warning, Watts tells the reader to consult local building and plumbing codes before installation, and to follow the local codes if the manual is not consistent with them. The sheet says the valve should be installed by a licensed contractor. It also says corrosive water conditions or unauthorized adjustments or repair could make the product ineffective. Since unauthorized adjustments or repair could make the product ineffective, stick to the strainer unless you know the rest.
### Who owns the valve?
The City of Phoenix says private pressure regulators are the responsibility of the home or business owner, and that the city does not regulate water pressure beyond the meter on the customer's side. That includes upkeep. If the valve serves your house, the upkeep falls to you.
### Why keep the setting the same?
The Building America Solution Center says the static service pressure in the home should be a maximum of 60 psi. Its guide describes the common direct-acting valve as one with an adjustable spring-loaded diaphragm and disc. The sheet's strainer steps do not involve the spring cage or the adjusting screw. If you find pressure has drifted after you clean the strainer, the sheet's other causes apply, and our page on how to adjust a Watts pressure reducing valve covers the setting.
What about the seat disc and the diaphragm?
Watts also gives steps for the deeper repairs, and they show why the strainer job is the easy one. To replace the seat disc, the sheet says to shut off the supply, loosen the nut (part 51), back off the adjusting screw (part 53), then remove the spring cage, spring and washer. You then remove the bottom plug and gasket, hold a screwdriver in the slot on top of the stem, and loosen the seat disc holder from the bottom of the stem. To replace the diaphragm, you loosen the lock nut (part 48) and remove the lock washer, diaphragm plate and diaphragm. When you reassemble, apply a drop of low strength thread lock to the disc holder.
That work changes the spring setting, so the gauge check applies. The sheet says not to bottom out the adjusting screw on the spring cage. If your valve needs a new seat disc or diaphragm, it is a job for a licensed plumber, and a repair kit from the sizes listed above is the right part.
When should you call a plumber?
Call if the strainer plug will not come out, if the valve leaks after you close it back up, or if pressure is still wrong after the screen is clean. Call too if the shutoffs on either side do not hold, since then you cannot service the valve without shutting off the whole house. HQ Plumbing & Air is licensed and insured, gives free estimates, quotes an upfront price, and offers 24/7 service.