Stuck PVC Valve

Can you shut off the water supply to the house without a bunch of trouble?

If you are able to, shut er down and open the tap. This will relieve the pressure on both sides of the valve, this may be enough to allow operation of the valve.

Are these 1/4 turn valves? If not, it might be wise to switch them out anyway. Probably not worth the hassle, never mind.

tried that..no joy. Even broke a handle off of one trying to rock it back and forth to loosen it. This happens even on brass ball valves. Must be silt build up turning into hard cement over time. Even though I have a.5 micron filter something must be getting through.

I will l change them out ,but I will find out why as I tear down the old ones.

Wow, enough buildup to jam a ball valve. Do you also have the common symptoms of hard water?

When I hear PVC (or CPVC) piping I presume the valves are glue in? If yes, when you cut them out there will likely be a shortness issue with pipe length.

Well, if the valves are busted they have to be changed, that’s the end of the line. Best of luck to ya.

Thanks HiTekRedNek, when you find out, can you let us know what caused the jam?

You should also consider not replacing the stuck OPEN valve, but just adding a second shutoff valve.

If you end up cutting the pipe to remove it, install unions on each side of the new valve. At least it will be easier to remove the next time you have to replace it.

Well, if you don’t mind this look in an under sink valve, a PVC valve/union combination is available.

I dunno… if there is a valve fail you would have to acquire the same brand, and the way things are today, who knows if the selected manufacturer will be around?

Might be best to glue on a pipe thread adapter, then thread on a common chromed under sink valve.

I have seen many that would not turn by hand. The rubber O-ring binds to the metal shaft. Get some WD-40 and spray it then get some pliers and turn it off.

Let me say that I have had this same problem and swapped the valves out for Stainless steel ball valves which are rebuildable.

Just drain the system, cut the old PVC out and install a threaded in ball valve using an adapter to glue to the PVC pipe and if no movement of the pipe is a problem then use a ball union.

The problem with the valves I found on dissection was that the PVC had shrunk and there was a plastic white powder filling the bearing space and locking the shaft solid.

I have changed out all the PVC valves for rebuildable SS valves.

As you have a 0.5 micron filter I am presuming you are using Groundwater and not normal utility delivered water ? or are you filtering local utility water ?
It could be the local water hardness (what is your PH Value ?)
The best way is to warm the bottom of the Vavle to around 80°C, this will not damage the plastic but will allow it to expand quicker than the internal parts and should allow any limescale / sand deposits to crack and disperse when the water flows again.
Do not use the water while heating as this will cool the valve.
An alternative method (depending on distance to the taps) is remove the tap, siphon off the water in the pipe (assuming you can stop the flow elsewhere and then pour a mixture of 200g Baking Powder, 200g course salt, 200ml white vinegar and 200ml hot water down the pipe, leave to work for 15-20 mins then see if the tap moves..

I am thinking about MEK ,the pvc cleaner poured into the valve, with the input side blocked below the valve with plastic wrap packed in tight.

It will either fix or melt the whole thing nothing to lose at this point, going to swap them out anyway.

Maybe something helpful here

Note: A petroleum based product like WD-40 is not recommended.

From plastics manufacture, the valve components would have a very slight taper on both parts, a little like a morse taper.

There might be benefit to try to "lift" the spindle relative to the rest of the fitting to disengage the tapered parts.

Often when trying to turn a tap, we place extra effort onto the spindle part and potentially engage it even more tightly into the other part.

Could be totally wrong, just an idea.

I haven't tried this yet but I take note that PVC expands with heat more than you would think, so I would try heating the valve in a series of heat and cold cycles to see if it would free up....I would wrap the valve in a wet cloth and hit it with a heat gun...I usually internally coat any PVC valves with pure silicone spray or grease prior to installation and work it back and forth till it feels loose...also periodically open and close the valve as a maintenance ritual...