Watts 911 combo backflow protector (1/2" 9D-M2) / pressure regulator (1156F). Backflow protector started leaking yesterday; I would like to change it myself.

1. The left side of the pressure regulator is a sweated connection. The right side is shown in the attached picture. Given it is a 911 combo, can I just swap out the body of the backflow protector for one of the same size and use new nylon washers for the union nuts? It is just that this is a strange connection between the 2 components, that is not 2 separate ones.

I was reading another thread http://www.doityourself.com/forum/bo...ing-water.html and saw a comment from Grady:

I have a gate valve on the return to the boiler and a drain at the bottom of the boiler.

2. If I turn off the power to the boiler, and close this gate valve, then will the only water that will drain out be the water in the boiler and the water in the 10' length on the feed line up to the zone valve?

3. How much water needs to be drained to get to 0 pressure?

4. After I refill the boiler, do I need to purge the zones? Or will any air in the boiler just escape from the air vent over the air purger/expansion tank?

5. And following up on Grady's suggestion, how do I relieve the pressure to change out a bad part if I have a valve as he suggested? Sounds like no draining of the boiler is required?

6. Can I extend this idea somehow to the expansion tank? A sticky I found by NJ Trooper stated to change the expansion tank, I had to get the temperature to less than 100 degrees (easy), and reduce the pressure to 0.

Thanks,
Newbie

 

If you have flow checks and or ball valves on the supply you want have to purge. If you have an air vent, close it when you drain. That'll pull a vacuum on the boiler and you will get less than a gallon out. Just make sure you open the air vent when you refill the boiler. Now I'm not saying that this is the right thing to do but I've seen people put a half inch boiler drain in the vent if the 9d. The vent really doesn't do a lot. It's not a relief valve. If it were my house I would just replace it. They're sold at home depot. The feeder us probably OK so just replace the 9d. When you break the 2 nuts just make sure you get all of the old gasket off. The new washers are plastic. It's easy and shouldn't take more than 5 minutes

 

There has to be a valve on the left of the picture. Close that valve.

The 1156F valve spec indicates that there IS a check valve built in.

So you should have no problem at all.

If you are the least bit apprehensive about water squirting, you can open a drain valve anywhere on the system to drop the pressure in the boiler to zero. You should not have to drain more than at MOST a gallon or so. I'm sure it will be less.

When you've got the new one in, reopen the feed valve you closed and you should be back in business.

Do you have a diaphragm type expansion tank on the system? If so, now is the time to check/charge the air in that tank when you've got the system depressurized.

Read this for step by step instructions:

http://www.doityourself.com/forum/bo...sion-tank.html

 

NJ Trooper,

Yes, there is a gate valve for the water feed on the left of the picture.

The Watts pressure regulator is actually an SB1156F.

1. What does the "S" imply?

Dburr9,

There is no ball valve on the supply side other than the check valve in the pressure regulator noted by NJ Trooper.

2. Are you referring to the open drain vent on the underside of the 9D? If I put a boiler drain on it, then I could close it and stop the leak. But doesn't that defeat the purpose of the drain, and might it cause a problem to the backflow preventer or boiler by not allowing it to work properly? Possibly I am not understanding what you are saying.


A few general questions for anyone.

I was planning to install a ball valve on the feed side after the pressure regulator, or possibly after the expansion tank. However, the more I think about it, this is a waste of time and money. Based on a 1” pipe, the volume of water between the pressure regulator and the zone valves is ~.5 gallon. And ~1 gallon of water needs to be drained to drop the pressure to 0.

So if I install the ball valves, as I was considering, then all I accomplish is keeping that .5 gallons in the 1” pipe on the feed side of the pressure regulator or expansion tank.

BUT with or without an added ball valve, I still need to purge the system when I open the water feed. I was trying to come up with a way to avoid having to purge the system in the future. Grady's comment led me to believe there was a way to install valves and avoid purging in the future.

3. Is my thinking correct?

4. And if so, then I believe I can just drain this same 1 gallon from the boiler any time I need to replace say an air vent or the pressure relief valve. Correct?

Thanks for your inputs.

 

It means that a 'hack' has been at work on your system at some point.

You see those threads on the 1156 valve? There USED TO BE a 'union' connection there with a 'spud' sticking out that was what they were supposed to solder to. For whatever reason it appears that someone decided to solder the connection there... I can't imagine why.

Yes, it does defeat the purpose. The boiler will still work fine though. Water can still get through from domestic to boiler. It DOES mean that in the event of loss of water pressure on the domestic side that it is POSSIBLE in the case of failure of several check valves (there are MULTIPLE check valves inside the 9D, and one in the 1156) to have boiler water backflow into your domestic. It does have to be the 'perfect storm' of events for this to happen, but it is still possible.

Thing is, there are MILLIONS of systems installed throughout the US that don't even have backflow preventers installed at all. It's a relatively recent requirement (last decade or three) that most plumbing codes require them.

So, you rolls the dice if you do plug that vent.

IMHO, I think it's bad advice to suggest doing so.

Sorta... here's the thing: The less water you have to drain in order to service any component, the better. If you have a valve on both sides of the backflow/pressure reducing units, you simply close them and do your service. You don't have to depressurize the boiler at all, nor add any fresh water back into the system.

The idea is to never add fresh water unless you absolutely HAVE TO. Fresh water contains Oxygen and other gases. It's the Oxygen that corrodes ferrous metals in the presence of water, and the other gases (mostly nitrogen) are what needs to be driven out so that you don't hear the gurgling of bubbles in the system.

 

I figured that the drain is what was leaking. In a pinch a plug will work for a day or two but not long term. I see a lot of it out there and I always change them.

 

This installation seems to be sufficiently unorthodox that you should post a wider-angle photo covering several feet in all directions. There may be other issues that might best be corrected when you depressurize the system.

I'm thinking that when that silly solder joint was made to the brass pressure reducing valve, somehow excessive heat was applied to the backflow preventer, possibly boogering the internal seals of the backflow preventer.

 

Understood... but here's the thing... remember that anything you write here on the internet is 'cast in stone'. You can't take it back once you've said it. So to suggest defeating a safety device (which is what the 9D is in fact) is not a good thing.

If you do suggest something like that, be sure to CLEARLY SAY that this should only be done on a TEMPORARY BASIS and NOT a permanent fix.

Remember that we're not 'preaching to the choir'. Part of the responsibility of answering questions should be to EDUCATE the person asking the questions and any future readers.

Gil, those are excellent points...

Josko, give us more pictures. Let's see the whole system. It really will help us to help you.

 

No, I've looked at it closely and gone to my local plumbing store to see the Watts 911 combo; they look the same. I know my pressure regulator was changed a number of years back. The 911 has a sweat connection on the left side of the 9D-M2, and a threaded connection on the right side. The 911 comes with a 'special tail piece nipple' (from Watts tech support) that threads into the 1156. The union connection pulls this special nipple tight agains the 9D-M2. I'm guessing mine possibly looks strange because new teflon tape was used when the replacement 1156 was threaded onto the combo.

1. If I understand this, then I should be able to change out the backflow preventer without dropping the pressure. Just turn off the water feed, disconnect the 2 unions, swap 9D-M2 bodies. Correct?

2. And if I ever need to change the expansion tank, I could drain ~1 gallon of water from the system to drop the pressure to 0, replace the tank, and purge. Correct?

I was thinking of installing ball valves just above the pressure regulator and after the expansion tank. But doesn't sound like this is needed if my thoughts above are correct.

4 pictures of the system

Boiler and burner - both Weil McLain. Gate valve on the return, drain on lower right front, gate valves surrounding circulator pump.

Boiler Top - good pic of connections

Boiler Side View - Shows the 2 zone returns and air vents from the 1st and 2nd floor

Boiler Other Side View - Shows a 3rd sone coming off for the Amtrol domestic how water. I have ball valves on both the feed and return for this zone.

So what I was considering was:

- replace backflow preventer
- skip ball valves after the pressure regulator and expansion tank if my thoughts are correct above
- possible replace gate valve for water feed with a ball valve. i think it was leaking the last time.
- possibly replace the drain on the return (not in any photo, but just above boiler left side) since it was leaking ONLY when I opened it while purging - strange.
- changing out the air vents for ones with check valves

3. Is there a way to do this without draining the 2 zones upstairs? Possible just drain 1 gallon to drop the pressure, remove and replace?

Dburr9, NJ Trooper,

4. I welcome all modification suggestions. Doing the work is easy. Knowing what is best to do, what might also be desirable, and what not to do is where I am at.

Thanks

 

No... you don't have the 1156 that is supplied with the 911 combo, you've got a BRONZE B1156F valve, which to my knowledge is not available in combo with the 911. That bronze valve is better than the cast iron one that comes with the 911 combo.

This is what you have:


image courtesy supplyhouse.com

This type of valve is NOT intended to have a pipe soldered into it such as yours is.

more later....................

 

Agree, I don't have the 1156 supplied with the 911. It was replaced many years ago.

But it is not a soldered connection as per your picture. There are threads on the feed side of the 1156, the same as the 911 at my local plumbing supply store. No soldering at this connection.

 

OK, I see it now... sorry, I didn't realize that style of valve had internal threads also. So you're saying that what looks like solder to me is really teflon tape or pipe dope?

In a perfect world, yes. I myself would drop the pressure in the boiler in order that I didn't have to trust that the check valve in the 1156 really IS 'tight seating'. Of course, if you do find that after you loosen the connections on the 9D that it seems to be leaking back, you could just close the water feed valve at that time and let the pressure bleed down from the leaking as you change the 9D out. Chances are also just as good that the manual feed shut off valve won't seal 100%. In either case, just work faster as it drips.

In any case I would also throw a sheet of plastic over the boiler so you don't get water dripping into the controls and such.

No, not really. Even dropping the boiler pressure isn't going to prevent the water in the pipes above from coming out the hole on the bottom of the air scoop. It won't come out FAST, and if you can work fast you won't lose much water, but still... no, not really.

Too much work! Have we suggested yet to look at this thread:

http://www.doityourself.com/forum/bo...sion-tank.html

Scroll to the bottom and decide if you want to add the optional valves that are discussed there. All threaded connections, no soldering necessary.

Also, pay attention to the step by step instructions for checking and charging the air in the expansion tank. Your tank is an oldie... evidenced by the label not used for many years.

While you've got the system depressurized, perform the maintenance on the tank.

I'm not sure what you mean by this... explain please?

If you prepare the stuff you want to change and have it at hand, and can QUICKLY change the parts, then yes, you can do it. Unless you have valves to isolate the stuff 'upstairs' you will lose SOME water due to gravity. Yes, drop the pressure to zero first. Close any valves that will help the cause and keep the water in the loops.

ALSO... SCREW THE CAPS on the air vents down tight! They WILL suck air when the system is opened.

Spilling a little water is preferable to having to drain the entire system.

Got a wet/dry shop vac? Have a helper nearby with that in hand to minimize cleanup.

 

It is me who is sorry for doubting you.

I woke up this a.m. and realized what you were saying. The "S" was throwing me off because I did not see a soldered connection. I just went to the local plumbing store and looked at an SB1156F. Yes, it has a union connection with a spud sticking out for soldering. AND, yes, there are NO internal threads on it.

What I started with was "probably" a 911 combo. And when the 1156 failed years ago, it was replaced with the SB1156F, but hacked somehow so that the 9D-M2 special tail piece nipple was slotted into the non-threaded 1156 connection.

It does not look like solder to me (I've always seen solder as silver); it looks more like teflon tape or pipe dope. But that would imply that something had to be first placed in that non-threaded 1156 end so the special tail piece nipple could be threaded in. So maybe what I am seeing is solder??

No, this was done about 8 years ago. The backflow preventer just started leaking when I recently opened the system for some other work.


So back to the problem at hand, given it is the backflow preventer that is leaking, and I am trying to understand what else makes sense to do to the system if I am working on it.

Summarizing what I believe is correct:

- Yes, I can replace the backflow preventer body and union washers. Just disconnect the unions, and swap in the body. And save the new unions and threaded connections for future use.

- Yes, I can at some point in the future replace the SB1156 with an 1156. I would use the saved threaded connection of the new 9D-M2 and make a threaded connection to threaded connection between the 9D-M2 and 1156.

1. Agree?

So 2 key questions:

2. Given the 4 pictures of the system, if this was your system, what modifications would each of you make.

AND more importantly, when I started this thread, the leak was significant - about 16 oz. every 3 days. BUT I noticed a few days ago it had significantly slowed down. And over the last 24 hours, there is a drop or 2 at most. Possibly the leak has been affected by the boiler now running more frequently given Autumn has arrived in New England.

Whatever work I do on the system will be based on what your replies to # 2 are.

3. BUT if it isn't leaking now, might it have resolved itself and 'flushed' out whatever small debris might have been causing the leak? And if so, I can defer all this work until it starts leaking again if ever?

Thanks for all of your patience. This is how I learn. Great forum - good feedback!

 

Maybe solder... what if they were REAL hacks and used something like JB WELD?

Was this previous owner or while you lived there?

What it appears to me is that there was a 'combo' there at the start, when they got the new B1156 valve they realized it wouldn't fit in the allotted space and came up with a " There, I fixed it " solution by jamming the parts together.

You could take a knife and scrape at that blob, might be silver underneath, or you might find it's epoxy.

For now, being that the heating season is upon us, you could just replace the 9D and leave everything else as-is.

Next spring/summer, sure... you could re-do the water feed in a more proper fashion.

Remember, there's no reason that the 9D or the 1156 have to be horizontal, you could even re-route the feed pipe and mount them on the vertical section... or one on the vertical, and one horizontal... or whatever.

IMO, you are best to stick with a bronze valve though. I don't care for the cast iron ones. It's fresh water flowing through there and they will rust up over time.

The B&G FB-38 is another example of a bronze valve.

Since I'm so OCD and AR, you really don't want to get me started on that! Trust me...

It may in fact stop leaking altogether as the check valves 'seat' themselves again.

 

There is teflon tape hanging out of this hacked connection; not worth scraping some of it off to see if there is solder under it. A BIG hack it is, a BIG hack it remains. I am the original owner, so it was done probably when the original Weil Mclain G04 failed ~7 years ago and the person installing the new one was raising the pressure reducer lever to speed up purging. It failed then and he replaced it. I watched, but don't recall what he did 7 years later. Too bad I didn't have the knowledge I have now back then.

The new 9D-M2 should arrive tomorrow. While I could wait and just temporarily plug the vent pipe if it starts leaking significantly again, I'm going to be conservative and just replace it given it is already paid for.

I came up with a laundry list of modifications to the system (basically ball valves, some with drains) strategically placed to isolate components. However, after thinking about it, my motivation is to reduce the purging time in the future. I could not convince myself that the cost (~$200 for parts and labor) was worth it for the benefit. I know how to purge, so I'll wait for things to fail if and when they do.

And the next house I buy, it will all be done right from the get go.

My thanks to everyone who has contributed on this thread. I have learned much.

Thanks!