Second backflow preventer still leaking

Hello all. I have a backflow preventer installed on my boiler system on the auto feed line for my boiler. Right before the backflow is the shutoff valve. Right after is the auto feed regulator as a backup to the systems auto feed regulator. There is a check valve in the boiler to prevent backflow of water as well as a check valve on the auto feeder I have, and a pressure gauge reading 12 PSI. The water coming in is right around 60 PSI.

My first backflow preventer was really leaking, almost a constant flow. I got it replaced but the new one is now only occasionally leaking. It does about 2-4 drips every couple of seconds. At first I thought that it would be caused by a fluctuation in the pressure. I tested this by turning on and off a faucet I have installed on the water lines coming off the boiler. When I turn them off and on I can hear almost a pop sound coming from the end of the vent line. I figure that sound is from the check valves clamping down to prevent the water from entering the water main. However I don't understand why I am getting inconsistent water drips. The drips even happen for a while when I turn the shutoff valve off. The boiler is off so the auto feed is also shut. I figure that would eliminate any "Fluctuation" problems because now the backflow preventer is holding 60 PSI constant in that line. I installed it right out of the box.

I thought maybe installing a check valve somewhere before the backflow preventer might help keep fluctuations from causing issues but that doesn't seem to be the problem. What should I look for?

Update: Took it apart to try and see if there was any debris in it but it was pretty clean. There was a film around the gasket that flaked around and I got all of it out and cleaned it but it's still doing the same thing. A new backflow preventer shouldn't be doing this I don't think lol

Here is the backflow I bought: https://www.supplyhouse.com/Matco-Norca-BFP-90-1-2-CLF-1-2-C-x-C-Backflow-Preventor-Lead-Free

I might just go with a different brand. I was looking at https://www.supplyhouse.com/Caleffi...l-Check-Backflow-Preventer-w-Atmospheric-Vent the measurements are the same so I would be able to make a direct replacement since I have threaded ends on my current matco version. I don't particularly care about a backflow preventer so I went cheap, but this is ridiculous. It should at least work without a constant drip. There is no chance of back pressure as the gauges are reading only 12 PSI vs 60 PSI. And the 60 PSI is being reduced from 100 PSI. I got plenty of consistent flow coming from the city. Do you think its best to just find another brand and try them?

what would try is aspring loaded check valve within a foot on the potable side.....any time I install a backflow device I automatically do this flushometers will make it drip
commercial kitchen spray hoses...anything quick closing...

Geofd said:

what would try is aspring loaded check valve within a foot on the potable side.....any time I install a backflow device I automatically do this flushometers will make it drip
commercial kitchen spray hoses...anything quick closing...

Click to expand...

you could also install gauges on both sides of the divice to see if there are pressure changes

mdk0420 said:

I might just go with a different brand. I was looking at https://www.supplyhouse.com/Caleffi...l-Check-Backflow-Preventer-w-Atmospheric-Vent the measurements are the same so I would be able to make a direct replacement since I have threaded ends on my current matco version. I don't particularly care about a backflow preventer so I went cheap, but this is ridiculous. It should at least work without a constant drip. There is no chance of back pressure as the gauges are reading only 12 PSI vs 60 PSI. And the 60 PSI is being reduced from 100 PSI. I got plenty of consistent flow coming from the city. Do you think its best to just find another brand and try them?

Click to expand...

are you treating your boiler with chemicals??????

Can't quite follow your description. You have 2 check valves in addition to the subject atmospherically vented double check valve?
What exactly does this mean..."Right after is the auto feed regulator as a backup to the systems auto feed regulator."?

It's not unusual to get some drips from very slight pressure variations, which the device may start to respond to. "Water hammer or "elastic shock" will cause them to spit from time to time. Often this is caused by a fast acting valve closing, like a washer machine fill valve, even dishwashers and ice makers. It is more common if the home has high water pressure."
The manufacturer of one of the best known version of this device( Watts 9D) has in the past, recommended a check valve be added downstream of the backflow preventer. But it sounds like you already have one.
I would call the manufacturer of the device and explain the problem to them and if they have been around for a while will likely know the likely causes and solutions.

Its a controlled system at the moment. There is no water hammering or anything going on that is causing it to drip with fluctuating pressures. I tested the water hammering effect by quickly turning on and off the quarter turn faucets I have coming right off the boiler. There are no chemicals treating the boiler, how would this effect it though because I had plans to do that before I put the boiler into service?

Its exactly how it sounds. The boiler itself has its own auto feed. Even though it has its own auto feed the setups I've seen still had their own auto feed on the feed line. So I copy catted them and did it as well. There is a check valve at the boiler and a check valve at the other auto feed (Which also has a pressure gauge on the outlet end). Then there is the dual check valve (Backflow preventer) and finally a shutoff valve for service.

Geofd I did. I have a water pressure gauge hooked onto the faucet. The supply pressure is at 59 PSI, the feed line is at 12 PSI after the regulator. The boiler is not running so there is no way the pressure is building on the boiler side (Its actually drained atm). The water is stuck between the boilers auto feed and the feed lines regulator which has a check valve. The only pressure it gets is from the supply line which can't pressurize the feed line anymore because its already at 12 PSI. I've been pulling the backflow preventer on and off trying to clean and reseat it but it just isn't fixing the issue. The pattern of dripping changed. Now its a consistent but very slow dripping. About once every 30 seconds or so. Better then the 3 drops every 10 seconds or so.

I did hear that flushometers can cause serious issues. I was thinking of putting a check valve right before the shutoff valve so it can counter surges like that, but the pressure is extremely stable in the house and doubt it'll be an issue. I have 100 PSI backing the 60 PSI I have it regulated to. Flushing toilets and using multiple water sources hasn't caused any decrease in flow to other lines since I've moved here. I don't use flushometers anyways, I use the Korky Quiet Fill Valves. Not sure if that would make a difference but they have a much slower fill (unfortunately).

I'm thinking that its probably a nip in the seal or something. I'm going to try to clean it up one more time under a sink and rinse it real good and see if it stops. If not I'm just going to return that one and buy the caleffi. Although I'm not sure what tool I need to be able to take off the caleffi male end lol. It came with a nipple that has a compress fitting on one end and a MPT on the other end. I have the backflow preventers fitting threaded onto that. The issue is there is no clearance to be able to get a pipe wrench or any kind of pliers onto the pipe to be able to unthread the backflow fitting off of it. Instead its designed to be held from the inside. It has 2 notches on opposite sides inside the nipple. Tried looking it up but can't really find anything on it. Not sure if its a common plumbing tool or more of a specialty tool for caleffi auto feed regulators

Well my hopes are up that I fixed it. I did that thorough cleaning like I said I would. I took it off, took a sponge and washed all the brass parts, rinsed off all the seals, and there was actually a seal that I missed. There is a center cylinder that I didn't realize pops out. It also has an oring around it that seals against the inside of the body. It didn't look bad but since it was a seal I missed, I'm hoping that might've been the issue. Been 15 minutes so far and no drips. Time will only tell. I'll do a test as well by shutting off supply and running one of my faucets to drop pressure. See if it does anything. I'll do that tomorrow. For now I'm just gonna put a dry bucket underneath and see if it is wet tomorrow.

If you ever have to replace it again put in a Watts backflow.

TomFOhio said:

If you ever have to replace it again put in a Watts backflow.

Click to expand...

Yeah I'm tempted to replace it. Although my last attempt might've fixed it. I didnt trust it so I turned it off last night instead or letting it on the whole night. But before shutting off I did test it by removing pressure and it dripped a little. Waited like 15 minutes and it seemed like it stopped again. I'll test it a little more and see what I have going on otherwise I'll get a replacement. Are the watts also 4 3/4 for the half" version? It seems like that's almost a standardized size for each replacement lol

Forgot to update. The thing is junk. It held fine until I did that test to make sure it would activate when a pressure drop happens. It hasn't stopped dripping since. Not gonna keep bothering with it. Grabbing a Caleffi and being done with it. I heard the Watts D has spitting issues. Which shouldn't be a problem for me but Caleffi seems to be a more reliable brand. Their pressure reducer/auto feeder has been fine so far and I know I can do a direct fit from it.

we here an mass use watts 9ds all the time I think they are great...but...everyone has an opinion good luck

Same here Geofd. Sorry I never heard of the brand Caleffi. If you like that brand then I would use it.

I learned many many moons ago, never ever use pipe dope on a d ck PFP
the oil makes it leak.
always use teflon tape
and use a watts, the other is garbage
or as my helper would say
no wino per s**h**i**t

Yeah the matco is definitely garbage. The Caleffi looked way better when I opened it up construction wise. Felt like it was twice as good (better be since its twice as expensive lol). Held no issues. Did my backflow test and it "spitted" like it was supposed to. The matco never actually spitted, it simply continued to drip, just a little more frequently. Right after the spit it did a few drops from what was left in the pipe but about 15 minutes later everything was dry again.

I have a question with these things though. I don't have a floor drain but I have a condensate pump for the boiler. Is there any reason I can't run it to the pump instead of just a couple inches off the ground? It can't really destroy a whole lot besides things that are laying on the ground since its all concrete but I rather not have a scenario where something fails catastrophically and it gets any carpets or boxes soaked and cause a mold issue. Or if there ever was a backflow issue for some reason I would like the spit to go to the pump.