Boiler Back Flow Protector Leak


  #1  
Old 08-13-14, 02:35 PM
J
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Boiler Back Flow Protector Leak

Started a new thread specific to this ...

The vent on the back flow protector is leaking. However, it sits right next to the pressure regulatorName:  Boiler Piping.jpg
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Size:  40.2 KB (see picture). The leak started only after draining and purging the zones for some required plumbing work (raising one heat vent for tiling a bathroom). I fill a 32 oz. container in ~4 days.

I have a back flow protector on the main water line coming into the house. So the back flow protector on the boiler would seem to only be protecting me from myself; that is some containment being introduced into my drinking water system, but not the town water.

A few questions:

1. I could cap this dripping vent - the easiest fix. Not sure what the plumbing code is. Would doing this in any way effect the performance of the boiler and/or oil burner now or over time? Or possibly cause the back flow protector or pressure regulator to leak around their gaskets?

2. If capping is not recommended, then how can I determine definitively that it is the back flow protector and not the pressure regulator, or both?

3. Draining and purging the system to replace the back flow protector or pressure regulator is a pain. So if I need to replace one or both of these now, I am thinking about how to do it more easily in the future.

If I placed a drain and a ball valve on the vertical pipe right after the pressure regulator (see picture), would I be able to just turn off the water feed to the system, close this ball valve ,and release the pressure on these components by draining the very little water between the water feed and this ball value?

This would avoid having to drain and purge either the heating zones or the boiler in the future when these components might go bad.

4. And if so, then if I added one more ball valve right after the expansion tank, could I also replace the tank without having to drain and purge the system?

And if I need to change one or both of these parts out, I might as well upgrade the system and replace a few gate valves with ball valves, and also use ball valves to be able to isolate each of the heating zones.

5. When isolating each of the 3 zones, do I need ball valves on both the water feed and return sides, or just one of them (which would be better)?

I just had an oil company person out to look over the system prior to getting oil from this company; he suggested the ball valves are just needed on either the feed or return. But this does not make sense to me.
 
  #2  
Old 08-16-14, 01:55 PM
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The device shown in the center of the photo is a Watts boiler fill valve, not a backflow preventer. We need to see more pictures from different angles, including wide angle views so we can see how things all fit together. Also, mark a photo to show exactly where the leak is coming from.
 
  #3  
Old 08-19-14, 06:31 AM
J
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The device shown in the center of the photo is a Watts boiler fill valve, not a backflow preventer.
Agree, the device with the lever is the fill valve/pressure regulator.

The device to the left of it is the Watts 1/2" 9D-M2 back flow protector. The pipe extending vertically from it is the vent pipe that runs across the boiler and down its side. It is this pipe that is leaking.

I believe this picture is sufficient for my questions.

Questions 1 & 2 are related to this leaking vent.

Questions 3 & 4 show the components I am considering isolating with a drain and 2 ball valves for ease of replacement.

Question 5 is a general question regarding isolating the various zones using ball valves.

Hope this helps.
 
  #4  
Old 08-19-14, 04:12 PM
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Re-build kits for Watts backflow preventers - but for not much more $, you can buy a new one. Adding ball valves for future maintenance is a good idea - need to isolate from the city water supply and the heating system itself. No need for a drain valve to relieve pressure - just loosen a union on the backflow preventer.
 
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Old 08-20-14, 11:34 AM
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Thanks.
1. I could cap this dripping vent - the easiest fix. Not sure what the plumbing code is. Would doing this in any way effect the performance of the boiler and/or oil burner now or over time? Or possibly cause the back flow protector or pressure regulator to leak around their gaskets?

2. If capping is not recommended, then how can I determine definitively that it is the back flow protector and not the pressure regulator, or both?
 
  #6  
Old 08-20-14, 01:49 PM
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Capping the vent defeats the purpose of the backflow preventer, so is not recommended. If the pressure reducer leaks, it would leak from the city water supply into the boiler, not the other way around, causing the system pressure to steadily increase and the relief valve would eventually lift.
 
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Old 08-25-14, 10:43 AM
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Here is the plan - measure twice, cut once

Time to make these changes to my boiler system (see new picture). The goal is to avoid ever having to drain and purge the system again after this one final time. Work to be done is:

1. Turn off the water at the water meter, turn off gate valves on the feed and return to the domestic hot water heater, turn off the 2 gate valves that isolate the boiler itself (one above boiler top on return (left) side of boiler, the other below circulator pump on right side of boiler), and drain the first and second floor zones.

2. Replace the gate valve on the 1/2” boiler water feed (above the backflow preventer but hidden in the picture) with a ball valve.

3. Replace the leaking Watts ” 9D-M2 Backflow Preventer. The label says it's 1/2”, but the M2 implies 3/4”. This seems a contradiction????

Update - I just talked with Watts. The repair kit for the 1/2" 9D-M3 will not work in the 1/2" 9D-M2 that I have; ditto the repair kit for the 3/4" 9D-M2. So I have no choice but to replace it. The 1/2" 9D-M3 is the revision of the device I have and what I need.

4. Cut the vertical 1” pipe to the right of the pressure regulator. Install a ball valve and a drain so that either the backflow protector or pressure regulator can be replaced in the future without draining the zones. I know gilmorrie said I could just loosen a union at the backflow protector, but then the water would just spay out over everything.

5. Cut the horizontal 1” pipe to the right of the expansion tank, but before the split for 3 zones. Install a ball valve so that the expansion tank can be replaced in the future without draining the zones.

6. Replace the turn spigot on the left vertical boiler return with a ball valve. When last purging the system, it was leaking significantly.

7. Replace the 3 air vents (2 upper center of picture, 1 on top of boiler) with Caleffi 502710A 1/8” NPT air vents that come with a check valve. I plan to first see if I can buy the check valve separately since the air vents are fine. This will make any replacement of the air vents easy – no draining and purging the system.

Have I missed anything? Any other comments on my plans?

Thanks in advance for the feedback.
 
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Last edited by jdbs3; 08-25-14 at 11:17 AM.
 

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