I had previously posted about this here:

[www.plbg.com]

but I never resolved it as other projects got in the way. Now I am back on it and want to try and fix it.

It is a valve box installed by original builder in 2007, CPVC piping 1/2", compression connections.



The cold water valve is slowly leaking when the lever is completely shutoff...these tiny levers are hard to get a leverage on so I used a plier to make sure it's 100% hitting the stops. It's not the end of the world as it leaks slowly like one drop every minute into the drain next to it and when connected it doesn't make a difference. HOWEVER, it was a real pain to move that 370 pound LG washtower out of the tight closet to begin with so I would like to properly fix it while I have it out of the way.

Previously my concern was if I were to loosen the compression nut, there is a risk that the CPVC pipe may slip under the hole if it's under some tension and not strapped behind the wall. This is no longer a concern because while I worked with a few of the same CPVC compression connections under the kitchen and in the bathrooms, I found that the chance of this is zero due to the brass ferrule on the CPVC is strangled to the point the ferrule cannot be removed without cutting therefore the compression nut and ferrule will act as a stop. I guess I am OK with not replacing the compression nut and just reuse the old nut and ferrule.

I plan to replace both hot and cold. The cold is leaking and I think this is an exception most times the hot side leaks first.

My first attempt was to find the same valves from Oatey, red and blue, 1/2" compression with hammer arrestors. Oddly enough I couldn't find the same ones or similar ones, not compression anyway.

So now I am thinking may be I will just get a new set of valves from other manufacturers like Dahl or whoever that does not have hammer arrestors. Do you think the hammer arrestors made any difference in reducing noises after 18 years (was put in 2007)? If it didn't make loud noises when I used the washer 2 months ago with the 18 year old hammer arrestors will it be OK to use new ones without hammer arresters? Those also have an advantage of a top side lever that is easier to operate than the side ones that are always interferred by the drain hose.

Finally, if I can't make it work, my plan B is to use these inline garden hose stubby shutoffs one on cold one on hot, and I think there may be room - need to confirm - that will not be in the way of pushing the LG tower all the way back to allow closet door to close.

OK some new development.

I just looked closely at the valves themselves, something I failed to do because I have been replacing the other valves in this apartment in the last month and all of them were compression connections to CPVC.

Now that I actually put a flash light onto the valves I can read that it says it big letters 1/2" NPT CONNECTIONS.



If this is true, than the bottom nut is NOT a compression nut, but a tapered female fitting connected to CPVC pipe below. In other words, I should be able to hold the nut steady with a wrench, and undo the valve by rotating the valves counterclockwise?

I have always dealt with MPT/FPT, I know NPT is tapered, so if I find NPT threaded valves, is it mated the same way with pipe dope, tightened by hand until snug, then do say another full turn with a wrench or do I need to do something different with tapered threads?

I called Oatey and their technical support said I should be able to hold the nut and unscrew the valves and screw back in any brand 1/2" MIP valves. I asked if I can connect a 1/2" MIP into a 1/2" NPT female fitting they said "it should"...is this true?

I remember reading here that tapered threads sometimes will stretch the female fitting and a straight threaded male will not seal right. Any thoughts?

Also pipe dope or tape or both?

They are all the exact same tapered threads, so thread them on as you have always done. Straight threads are NPS

I don't count turns, I go by torque.

If using dope, ensure it is compatible with CPVC.

george, I am now thinking the Oatey technical person is wrong. If you look at the picture there is no way you can rotate (thread) the cold valve in without hitting the hot valve with the spout or the handle. I don't think this can be a NPT threaded connection.

I think the sticker on the hammer arrestor saying this is a 1/2" NPT connection refers to the connection between the actual hammer arrestor and the top of the valve.

Cut open the drywall below box,cut out cpvc, install the Sioux Chief 1/2" cpvc to copper transition fittings you used for kitchen sink, stubbed into the box, install compression washing machine valves (I like Dahl 1/4 turn valves - can even get them with color coordinated handles), install water hammer arrestors on the connections on the back of the washing machine (they are elbow pattern and do not take up much room) and patch drywall.

In the future will be able to change out valves/arrestors without any problems...just my 2 cents....

I agree Curly

Curly,

I get what you are saying, and cutting open the wall is an option that I'd rather avoid because I just painted this entire apartment including this closet LOL, plus being that this is inside a mid rise apartment the framing is made of metal studs not wood. Every time I cut open the wall I have had to go through extra steps to rig something up...for example, with wood you can laterally screw in a short piece of sister as a nailer for the replacement sheetrock patch, with steel it is not as simple because the members are U shaped and filmsy I can twist and bend with my finger.

Oatey basically told me the same thing which is it is unlikely I can unthread the cold valve without the hot valve handle not to interfere. So I would have to unthread the hot side first just to have room to unthread the cold. So how did someone put both in originally? They said most likely you will have to thread in the hot side but not 100% tight, then do the cold and get it into position, then thread in the hot side tight facing out. So what if I thread one in and when it's 100% tight it does not face out and you have to tighten another 270 degrees? Oatey said in that case you would have to open the wall and cut the piping so you can rotate to where you need them and put in a coupling. I said my guess is they were installed and tightened with a short piece of pipe unattached below, when it's all connected above and oriented properly they get attached below with couplings.

In general I think these washing machine boxes are not well designed while it looks neat not much thought was put in on servicing and maintenance.

OK one last thought.

Let's say I am able to unthread the two valves from above somehow, by cutting the levers off so there is room to rotate them off the 1/2" NPT fitting (which I am not sure it is and not compression), What if I connect to it a fitting that gives me a short stub of 1/2" copper for compression connection? For example:

(1) a 1/2" copper male adapter that on one end is a FTG/spigot and on the other end 1/2" MIP. If I thread this onto the female NPT and able to make a leak proof connection, does the short stub gives me enough pipe to connect to a compression valve?

(2) a 1/2" regular male adapter pre-soldered to a 2" piece of copper tubing. Thread into the female NPT followed by a compression valve.

Would either of these two options be worth a try?

Would these valves, being compact, thread on to the FPT fittings?




Edited 1 times.

george I think they will. I took the valves out today, and they are indeed threaded valves not compression.

[img[]https://i.postimg.cc/0yb6vPT4/IMG-20241218-152322.jpg[/img]

I plugged them with 1/2" plastic plugs.



Since Oatey no longer carry the same type of valves, I think I will try a male adapter soldered with a short piece of copper and go compression.

I like the dahl you showed they make a compression connection one I think I will get those.



Edited 1 times.

Hi Sum,

Sorry for the late reply.

Option "1" I don't think street(fitting) male adapter would give you enough copper tube for the compression fitting.

Option "2" would be a better choice.

Here is part number for Dahl color coded compression washing machine valve : 611-33-04-PK2

They also make it with 1/2" mip connection : 621-01-04-PK2 if you want to thread directly into your fitting.

Good Luck.

curly, I will go with option #2.

I think the 1/2" MIP version would work too but I am concerned about having it tightened up and it's facing the back and I have to do another 180 turn and I can't get a wrench on the flats on it's back at certain angles since it's so tight I would have to bite onto the hose connection spout and ruin the threads.

What is the minimum copper stub needed to make a compression connection? Is 1.5" enough?

Yes.

That allows just enough room for the compression nut slide back and exposed ring so it can be removed in the future.

A little more would not hurt if possible.

I would go with the MPT valve and thread it directly on to the FPT fittings. One less joint and less stress on the pipe threads from the hose because of less overhang.

There might be enough space behind the fitting to use a 13/16 crowfoot socket on the valve body. Failing that you can fit a cap on the hose threads to protect it and then wrench on it.

Sum, are those nuts tapered pipe or is there a ball sealing surface inside and the nuts are straight thread?

steve, I am not sure how to tell if the threads are straight or tapered. I assume tapered because the old valves stated "NPT CONNECTIONS". If tapered than it is possible to overcrank the male threads to loosen the female nuts? The Oatey rep I spoke to said I should be able to use MIP fittings on it.

This is what the nuts look like after I removed the valves.

Check the threads on the valves that were taken out. Use an adjustable wrench to see if the diameter is uniform or if there is a taper.

Get one of these wrenches in 13/16.



Wrench + 3in extension + ratchet will enable you to thread on the valve. If more clearance is needed, grind the throat of the wrench further

george, great tip on using a hose cap to stop the threads from being damaged. I have to remember this next time this happens.

I got the compression set of dahl valves ordered so it's on it's way.

it's kind of hard to tell. To me it seems tapered, but the male adapter next to it that I just soldered also look tapered a little yet I know MIP is straight threads.

The taper on the valve threads are easily visible. The copper adapter threads are also tapered though not as obvious in the pic. They are MPT - male pipe tapered



Edited 1 times.

George do you think the copper adapter will seal against the female nuts?

Yes, it will. They are both tapered.

Dope + tape for extra insurance.

I got this done today...but was careless and made a big mistake, will post in another thread.

But as far as these valves, I first threaded in the male adapters and no leak.



Than onto the copper new washing machine valves compression connection, no leak.