REPLACING 3/4" GATE VALVE ON CPVC COLD WATER

[MACPLUMB]

Hey out there try to make a short story,
because or hurricane water damage have a company doing repairs though out
apt complex, came out last Saturday pulled everthing out of my storage unit
including water heater, they cut out drywall whist high then replaced and taped
installed a new electric water heater,
OK came out this morning to pull water heater so they could texture and paint,
they shut off water at a 3/4" gate that feeds cold water to my Apt,
so been without water all day, Came by at about 4;30 pm to reinstall
water heater Main Gate was broken, so no water they shut down at 6;pm
and left me with no word,

Problem;
this is a three story apt building they are going to have to shut down building to replace gate valve, and drain down
#1 Cold water draining down from upper floors could cause dry firing elements unless they go into each unit and turn off power to heaters yes/no ?
#2 what would be the simplest way to remove and replace that valve causing
the least about of water leaking out it is threaded onto a male adp. ?
#3 the maintenance Mgr. came by this evening to apologize, they do not know where to turn water off to the building, I am in building 3 they have the shut offs for the other buildings but not this building this complex build in 2006 and all plumbed with CPVC piping
starting tomorrow morning they will get together with the contractor
to solve problem !

 

[Reach4]

#1 Cold water draining down from upper floors could cause dry firing elements unless they go into each unit and turn off power to heaters yes/no ?

Any chance the draining water could create a vacuum? I think opening a cold line to admit air on each floor might be a good idea. Ideally water heaters that connect to lower floors would have vacuum breakers, but I think those may be fairly recently used. I am not a plumber.

#2 what would be the simplest way to remove and replace that valve causing
the least about of water leaking out it is threaded onto a male adp. ?

Cut the pipe, dress the end, and shove on a SharkBite ball valve onto the CTS CPVC. Have the valve open when shoving, in case there is some water draining. Then close the valve. That should be pretty quick I would think, because it will not require drying out the pipe. I would put silicone grease on the pipe to meet the O-ring, but that is not the common thing to do I think.

 

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[Terry]

In this case, yes the Sharkbite style may be a quick way to go assuming you have some room there for it. If not, the threaded MIP won't take too long either. Most of the time you're okay with a shutdown that isn't too long. I've shut buildings down plenty of times where I didn't have access to water heaters. Some places like to see vacuum breakers on the cold supplies to water heaters on the upper floors for that reason.
Many dip tubes will have a small hole near the top to prevent siphoning, but you know how that goes. Sometimes they do.

 

[Jadnashua]

Three stories, probably about 30', about one atmosphere vacuum. Could get ugly unless you can isolate things.

 

[MACPLUMB]

I am on the first floor of a large U shape building about 65 units,
I do don't know what the water main is made of most likely PVC
just that the whole building is CPVC,

I got notice this morning that they are turning water off to the building at 2M,
to make repairs,

All water heaters have a weep hole about a 1/4 the way down to break the
siphon, but even if the upper element is only partially covered by water it can still be damaged a dry fire

 

[MACPLUMB]

The funny thing is this all started because they were replacing water damaged
drywall that had mold, you know they are going to get this new drywall wet
again !
this is a 3' x 6' closet with the heater set toward the left side in back

 

[MACPLUMB]

Just got water back on and the heater is on 5:30 PM
out since 8: AM yesterday