Please Help Explain My Main Inlet Plumbing (See pics)

[Geobrick]

After living in the same house for 17 years, I still don't understand what's going on with the plumbing for the main water inlet. While most of it is sort of straight forward, some of it I've never figured out.

Can one of the experts here help explain what's going on here? Especially on the right side of the first picture and all of the second picture.

 

[Reach4]

That mystery pipe might have started as a "softener loop". You can find references to that term.

Other stuff may have been added. I don't know what the bottom two lumps would be, but I expect they are some kind of coupling that was added in to let the other stuff get added.

 

[Sponsor]

 

[hj]

From its location, it could be some "cobbled" up part of the fire sprinkler system.

 

[Geobrick]

Thanks HJ and Reach 4. I'm thinking it's part of the fire sprinkler system too.

It looks like the bottom pipe on the right side coming out of the wall is at the same level as the one going into the wall on the left side so it's likely the same line.

I believe the two ball valves are there to allow you to independently turn off the main house inlet without turning off the fire sprinkler line.

Maybe the fire department requires the fire system pressure to be available for inspection on the outside of the house. I'm not sure why that system would be fed before the pressure reducing valve. That means it's exposed to whatever the street pressure is. The fire sprinkler piping is different from the rest of the plumbing system. It uses an orange colored pvc pipe while the rest of the house is copper. Perhaps that orange stuff can handle higher pressures (I hope).

Every time I look at that pressure gage, it reads about 115 psi but after I open the valve and release some water, the pressure drops to something lower (after the valve is closed). In this recent case, it went from 112 psi to 85 psi.

Here are the before and after pics.

 

[Geobrick]

Is it possible the two bulbous looking fittings at the bottom right side are some sort of check valve to prevent water flowing back into the main water line from the fire sprinkler system?

 

[Jadnashua]

Do you have an expansion tank in the house? IF not, that higher pressure could easily be the result of heating the water. When you have a PRV, you have a closed system, and heating water needs someplace to go. Since it's not getting even higher, it's likely that you have some valve that is leaking slightly, otherwise, that pressure could easily get to 150psi, and open up the T&P valve on your water heater. A common valve that can go unnoticed is the toilet fill valve, but any small leak when it gets higher, could be enough to relieve the pressure from getting high enough to open the T&P valve.

 

[Geobrick]

Do you have an expansion tank in the house? IF not, that higher pressure could easily be the result of heating the water. When you have a PRV, you have a closed system, and heating water needs someplace to go. Since it's not getting even higher, it's likely that you have some valve that is leaking slightly, otherwise, that pressure could easily get to 150psi, and open up the T&P valve on your water heater. A common valve that can go unnoticed is the toilet fill valve, but any small leak when it gets higher, could be enough to relieve the pressure from getting high enough to open the T&P valve.

Yes, I've read on these forums (maybe from you) about how heated water can do that when there's no expansion tank (and there's not one).
I'm pretty sure this gage is on the fire sprinkler line that comes off the main line before the PRV. I'll have to read up on residential fire sprinkler systems in CA to see what this whole configuration is. It was all built at the turn of the century (2000).

 

[CountryBumkin]

I'm not sure why that system would be fed before the pressure reducing valve. That means it's exposed to whatever the street pressure is. The fire sprinkler piping is different from the rest of the plumbing system. It uses an orange colored pvc pipe while the rest of the house is copper. Perhaps that orange stuff can handle higher pressures (I hope).

Fire sprinkler system must be independent (connected before) the rest of your home's water system so that if the PRV was to ever fail it would not restrict/stop water flow in the sprinkler system.

 

[Smooky]

Here are some similar check valves:
http://clearridgetruevalue.com/check-valves-c-33_204_988.html

http://www.nibco.com/resources/ProductSubmittalDocs/TS480BI.pdf

http://www.nibco.com/Valves/Special...80-Check-Valve-Ring-Check-Bronze-Solder-Ends/

http://www.nibco.com/resources/ProductSubmittalDocs/TS480YLF.pdf

For a sweat connection: NIBCO S-480
For sweat lead free Connection: NIBCO S-480-Y-LF

For a threaded connection: NIBCO T-480

 

[Geobrick]

nnected before) the rest of your home's water system so that if the PRV was to ever fail it would not restrict/stop water flow in the sprinkler system.

That makes sense but also exposes the system to the full main pressure (I'm sure they'd consider that in the design)

 

[Geobrick]

Here are some similar check valves:

Yes. They look similar.

I think we've figured out what's going on. The fire sprinkler system taps off the main line after a ball valve but before the PRV and goes through 2 check valves then to the rest of the fire sprinkler system.

On the other side of my house, is something close to the ground that looks like a special hose bib with no handle that says something about a "Inspectors Test". The bib has a copper coupler fitting on it to prevent putting a standard handle on it (maybe to prevent someone from using it for a hose). I'll post the pictures soon.

 

[Geobrick]

Here are the pictures of the placards related to the Fire sprinkler system.

This one is where the main water supply comes into the house. You can see where it's located in relation to the plumbing by looking at my first post.

This next one is on the opposite side of the house. Maybe this is used to flush the system.