I finally decided to handle that ancient pressure reducing valve myself after getting a quote for over a grand from the local pros. They were convinced my 150 psi water pressure was the reason my toilets were acting up, and honestly, the brass on that old PRV looked like it had seen better days. I have zero plumbing expirience, but I figured buying the part and some basic tools was way better than paying those insane markups just becasue the valve was sitting near a red-handled shut-off. It was a bit intimidating working with the copper lines, especally with the grounding clamp right there in the way, but I managed to get it swapped out. I ended up using a press-fit connection for the upper section wich saved me from having to learn how to sweat a pipe on the fly. The difference is huge now. The toilets acutally flush correctly and the pipes don't groan every time someone turns on a faucet. If you're dealing with high pressure and an old house, definitely check that valve before calling the big companies. It’s a relief to have it done and actually see the gauge sitting where it shold be instead of pegged at the max.
Just finished replacing my old pressure reducing valve and learned a lot
Sep 22, 2026
Last reply: 4 days ago
5 Replies
I did the same thing last summer with a Watts LFN45B. My static pressure was hitting 115 psi and my water heater's T&P valve was constantly weeping. I was nervous about messing with the main line, but those press fittings realy make a difference for those of us who aren't ready to fire up a torch near the floor joists.
One thing I learned the hard way was checking the thermal expansion tank while I was at it. Since a new PRV essentially creates a closed system, my old expansion tank had a ruptured bladder I didn't know about until the pressure started creeping back up overnight. I had to grab a 2-gallon Amtrol tank the next day to keep the gauge steady at 55 psi. It’s definatly a win to skip the professional markup. Just make sure you keep an eye on those joints for a few days. I wrapped mine in a dry paper towel to spot any tiny slow leaks that are hard to see on copper right away.
I went a diferent route beacuse I didn't want to rent a press tool or mess with cutting pipe if I could avoid it. I checked the casting on my old, crusty Wilkins 600XL and found the exact same unit at a local supply house. Since the original was installed with double unions, I didn't have to touch a saw or a torch. I just shut off the main, drained the lines, and backed off the union nuts with a pair of 14-inch pipe wrenches. The real challenge for me was the calibration. I picked up a dedicated pressure gauge that screws onto the laundry sink faucet to see what was actually happening inside. Even though the box said it was factory set for 50 psi, my readings were jumping around 65 psi. It took a bit of trial and error with the adjustment bolt to get it to a stable 52 psi. If you're doing this yourself, definitely grab a gauge rather than trusting the factory setting, especially if your incoming city pressure is as high as 150.
I'm looking at my own PRV and it's also got that grounding clamp right next to it. Does that thing just unscrew or is it dangerous to move? I relly don't want to get zapped while trying to fix a leak. Also, you mentioned using a press-fit connection—do I need a special expensive machine for that? I don't know much about tools beyond a basic wrench and I'm worried about the cost of equipment if I'm trying to save money on the plumber. Is there a way to do it without buying a thousand dollar tool?
I’m totally pumped to see people actually fixing this stuff themselves! I’ve been staring at my utility room for weeks afraid to touch anything, but this makes it sound so doable. I honestly had no idea water pressure could be that intense without pipes just exploding!
Quick question though—since you mentioned the toilets flushing better, does changing the pressure affect the hot water heater noise? My heater makes this wierd knocking sound whenever the dishwasher starts up, and I’m wondering if a new PRV would fix that or if it’s a totally different beast?
Good call on the DIY swap. 150 psi is a death sentence for your appliances. If you used a Ridgid RP 241 or a similar press tool, those connections are solid. For the person asking about the grounding clamp: it’s just a safety bond for your electrical system. Just loosen the screws on the Burndy clamp, slide it out of the way, and tighten it back down on the clean copper when you're done. No big deal. Just make sure you dialed that new valve—prolly a Watts LF25AUB—to 50 or 60 psi using a 0-200 psi lazy hand gauge. Leaving it at factory settings is a rookie move.
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