This Watts 9D-M3 Backflow Preventer Valve feeds water into our furnace, provides an overpressure relief, and prevents heating loop water from re-entering the potable water supply.
The vertical pipe leads downward near the floor, underneath which sits the small plastic bucket I provided to catch the occasional drip. Recently we had an all-hands scramble to soak up a pool of water spreading across the floor from the overflowing bucket, across the aisle, and below the shafts-and-rods-and-tubes-and-pipes storage rack. Evidently the occasional drip became a steady drip while we weren’t watching; not a catastrophic flood, but far more water than we want on the floor.
This is the inlet valve, which is basically a flapper. You can’t see the fine cracks around the central mount, but they’re all over the inner half of the ring.
And this is the outlet valve, which has pretty much disintegrated. Note the outer rim peeled back under my thumb:
A complete new valve is $40, in stock and ready for pickup at Lowe’s, but all I really needed was the failed rubber flapper valves, which they don’t carry. A few minutes of searching reveals the Watts 0886011 Repair Kit, which has all of the interior parts.
Pop Quiz: How much does the repair kit cost?
Answer: Starts at $38 plus shipping and goes up from there. Cheap aftermarket kits run $20 and up, but they’re all out of stock.
Now that, party people, is the sort of thing that ticks me right off.
Perhaps the local HVAC / plumbing supply stores have such kits in stock? To quote: “They may exist, but we don’t have them.”
I don’t see any way to homebrew new flapper valves, so it’s off to Lowe’s we go…
It would seem to me that these things shouldn’t fail after a mere decade of service. I thought that about the CdS flame sensor that crapped out in the middle of a sub-zero January cold snap while I was at Cabin Fever some years ago, too.
The Smell of Molten Projects in the Morning 
Comments
10 responses to “Watts 9D-M3 Backflow Preventer Valve: Failure & Aggravation”
I had a weird flame sensor failure a while back too. This was in a demand style water heater that used flame rectification to determine whether the pilot had light successfully. I saw the little rod in the flame and assumed it was a thermistor or pressure-driven, or some such. It turns out it’s just a solid rod. However, it turns out it’s a pretty high impedance way to detect flame, and this little rod was insulated by a plastic bushing that had become leaky over a few years. Most such flame sensor rods have a substantial ceramic bushing, which presumably resists leakage better. Once I realized it was just a heat-resistant rod, I picked up a random inexpensive one at a heating supply store (I had quite a time explaining to the guy at the counter that I didn’t care which heater it was designed for, I just wanted an inexpensive one that was in stock). I made a trivial bracket to hold the new, differently shaped, rod in position, and it worked fine.
Learn something new every day: I didn’t know about that!
I poked my nose into the oven to see if that ignition module had a rod on it. It doesn’t, but perhaps they use the entire glow bar as the electrode.
If I can come up with a good use for an open flame, I’ll be forced to use it as a rectifier…
Just in case you have not seen it, check out Nyle Steiner’s flame triode:
http://www.sparkbangbuzz.com/flame-amp/flameamp.htm
Flame speakers, yes, but flame triodes?
If I can figure out even a quasi-practical application for that, I’m all in…
Niche products for steampunk guitarists? ;-)
http://www.musicradar.com/news/guitars/10-ridiculously-cool-steampunk-guitars-197183
Y’know, I should start converting the contents of my Basement Laboratory Storage Wing into that kind of stuff: there’s obviously a market!
Backflow preventer Watts ½” M3-9D is very poor product. I keep changing them every 3-5 years
Unfortunately, it’s the only choice in the big-box home repair stores around here: it would be much less annoying if the repair parts kit was easily available!
Which brand do you prefer and where can an ordinary guy like me find them?
Thanks for confirming my findings, though… [sigh]
Got the same POS ….Had the same problem. I have a special hat I put on with a big “L” on the cap.
Did you have shut everything down and drain to change this?
They did a top-notch job on the installation, with ball valves upstream and down: two quarter-turns shut off the water, then catch a few drips as the nuts spin free. Not even any corrosion!