Can Moen Positemp Valve Go Bad?

[Rancho]

One plumber says they are super simple and there is nothing to break or go bad and another says maybe it’s defective and I should replace it.

The issue I have is that the hot water side keeps losing pressure and needing either new cartridges or to be blown out to clear some unknown debris.
Not sure if the debris is originating from the valve itself or somewhere else like the water heater. I would think I would get clogs on the kitchen and bathroom sinks if the debris was coming from upstream, but maybe these shower valves are just extra easy to clog up with something that doesn’t affect other faucets.

Does anyone have any ideas?

If I pay for a new valve and repairing the hole that gets cut to access the valve and it doesn’t fix the issue, that will be a huge waste of money.

 

[WorthFlorida]

Batches made around 200o-2010 were prone to the hot water side completely get blocked. The pressure balancing spool would just jam up, not sure why but it could have been minerals in the water. I replaced at least five of them including my own home, both sons I have had one each go bad and some friends. The replacement cartridges now have a black coating on the spool. When you remove the cartridge it should rattle when shaking it. If it doesn't then tap it on a hard surface and it might loosen it up, but it still needs replacing. Looking inside of it you'll see the steel rod. For replacements only use a genuine Moen cartridge.

 

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[Rancho]

Batches made around 200o-2010 were prone to the hot water side completely get blocked. The pressure balancing spool would just jam up, not sure why but it could have been minerals in the water. I replaced at least five of them including my own home, both sons I have had one each go bad and some friends. The replacement cartridges now have a black coating on the spool. When you remove the cartridge it should rattle when shaking it. If it doesn't then tap it on a hard surface and it might loosen it up, but it still needs replacing. Looking inside of it you'll see the steel rod. For replacements only use a genuine Moen cartridge.

Just noticed the reply because I’m not receiving email notifications.
The cartridges have been replaced over and over. Probably at least 8 cartridges in 5 years. Just replacing cartridges is not sustainable especially since I pay over $150 labor for each repair.
Sometimes the cartridges only last a day and sometimes a year or 2. The valve is from 2001. So, maybe it’s one of the bad valves
Does Moen have lifetime warranty on valves like they do for cartridges?

I’m thinking of getting the Positemp replaced with a Moentrol valve.
Is the Moentrol valve any larger than the Positemp? There is no rear access, so the plumber will need to cut tiles to make an opening to replace the valve and I’d like to just use the matching Moen remodel plate to avoid replacing the tiles. Will the same Moen remodel plate fit both Positemp and Moentrol handles? https://www.ferguson.com/product/moen-remodel-escutcheon-for-one-handle-tubshower-faucet-in-brushed-nickel-m1920bn

I was thinking of switching to Delta, but the Delta remodel plate looks so cheap and plastic. The Moen plate might also be plastic, but even if so, it can pass for metal.

 

[Jadnashua]

If your valve design uses one of these spool valves, that is more likely the source of your problem... Moen Balancing spool -- 1423 -- Moen
Maintenance: How to Clean a 1423 Balancing Spool - Moen Solutions

 

[Rancho]

If your valve design uses one of these spool valves, that is more likely the source of your problem... Moen Balancing spool -- 1423 -- Moen
Maintenance: How to Clean a 1423 Balancing Spool - Moen Solutions

That part is near the price of a complete valve. Why not just buy a new valve then? Can that part be replaced without removing the valve and needing to cut the shower wall to access it?

How would I know if the valve uses that part?
When I look up Positemp valves, I see several different versions https://www.ferguson.com/category/moen/_/N-zbq6mwZzbq5z5?collectionId=ProdFamily-4291213

 

[Rancho]

Batches made around 200o-2010 were prone to the hot water side completely get blocked. The pressure balancing spool would just jam up, not sure why but it could have been minerals in the water. I replaced at least five of them including my own home, both sons I have had one each go bad and some friends. The replacement cartridges now have a black coating on the spool. When you remove the cartridge it should rattle when shaking it. If it doesn't then tap it on a hard surface and it might loosen it up, but it still needs replacing. Looking inside of it you'll see the steel rod. For replacements only use a genuine Moen cartridge.

Would replacing just the balancing spool permanently resolve the problem or was there some other design flaw in those valves from 2000-2010 that would require replacing the entire valve for a permanent fix?

 

[Jadnashua]

IF your valve uses that type of spool valve, it is separate from the on/off cartridge, and yes, IF the spool valve is sticking, and you replace it with a new, working one, it should work fine until it sticks again. How soon would depend on your water...how hard it is, and if there tends to be any sediment in it that can clog things up. To check, you'd take the handle and trim off...if you have the large slotted head, you likely have that type of spool valve...the instructions posted showed how to change it.

Some cartridges have that built-in...some valves have both, and each is separately replaceable.

 

[Terry]

I saw this example here where the homeowner had very high pressure in the home. It pitted out the body of the valve.

 

[Rancho]

If your valve design uses one of these spool valves, that is more likely the source of your problem... Moen Balancing spool -- 1423 -- Moen
Maintenance: How to Clean a 1423 Balancing Spool - Moen Solutions

The plumbing company said they don’t think Posi-temp valves have that part. They said they have installed hundreds on Posi-temp valves and never have seen that balancing spool. So, that must just be for Moentrol valves.

 

[Terry]

The plumbing company said they don’t think Posi-temp valves have that part. They said they have installed hundreds on Posi-temp valves and never have seen that balancing spool. So, that must just be for Moentrol valves.

Moentrol, not Posi-Temp.

Posi-uses the 1222 cartridge, balancing inside the cartridge

Moentrol uses the 1200 and the 1225 for cartridges, and has a separate spool for balancing.

 

[Rancho]

Moentrol, not Posi-Temp.

Posi-uses the 1222 cartridge, balancing inside the cartridge

Moentrol uses the 1200 and the 1225 for cartridges, and has a separate spool for balancing.

So, it’s still a mystery why the Posi-temp would keep going through cartridges or need to be flushed out to clear blockages in the valve itself. No other faucets in the house including another shower that’s closer to the water source has this issue.

 

[Terry]

What year was the home built? Does it have galvanized piping for the hot side? How old is the water heater?

 

[Rancho]

What year was the home built? Does it have galvanized piping for the hot side? How old is the water heater?

House was built in 2002. The water heater is 5 years old. Don’t know about piping, but it would have whatever code required in 2002.

 

[Rancho]

If the Posi-temp valve needs replacing, I’d be interested in switching to a Moentrol so I can upgrade to control both temperature and flow independently.

Since there is no rear access, tile in green shower wall needs to be cut to remove the old valve. I would like a valve that is not larger in size than the Positemp so that the hole doesn’t need to be made larger than what can be covered with a Moen remodeling cover plate so that I can avoid having to hire someone to repair and replace tiles.

Are Moentrol valves physically larger than Positemp valves?

 

[Terry]

The Posi and Moentrol use the same size trims. If you have access to the back, it will be easy to change out the valve and trim.
Hopefully that would fix it.
New home, pretty recent water heater. And I have no idea why there are so many issues with the existing valve. It is really strange.

Have you pulled the cartridge, slipped a hose over the end of the valve and flushed to see if anything comes out?

 

[Rancho]

The Posi and Moentrol use the same size trims. If you have access to the back, it will be easy to change out the valve and trim.
Hopefully that would fix it.
New home, pretty recent water heater. And I have no idea why there are so many issues with the existing valve. It is really strange.

Have you pulled the cartridge, slipped a hose over the end of the valve and flushed to see if anything comes out?

There is no access from the back, that’s why replacing the valve is such an issue. A hole must be cut in the shower tile to get the valve out. We wouldn’t be cutting the tile if we could just access the valve from the back instead.
The question is about the physical size (dimensions like height and width etc.) of the valves themselves. Will a Moentrol valve fit in minimally cut hole just big enough to remove the Positemp or would a larger opening need to be cut in the tile to get the Moentrol installed?
Pictures I’ve seen of the Positemp and Moentrol valve look like the Moentrol may be a bigger, bulkier valve, but I can’t see anything that lists actual dimensions comparing the two.

I want to make sure the hole required to replace the valve can be small enough to be fully covered by a Moen remodeling cover plate.

We don’t see anything coming out, however, sometimes flushing the valve with the cartridge removed fixes the issue. However, it never fixes the issue permanently. The problem always comes back.
Sometimes just exercising the faucet handle by turning the water from cold to hot to cold to hot a few times causes the problem to return immediately.

 

[Jadnashua]

Terry can tell you stories about finding all sorts of things IN the piping. You might have something like a pebble, or who knows what partially blocking the line that moves around. When it is sitting just so, it gives you problems.

The remodel plates are sized so that a competent plumber has enough room to cut out the existing valve and connect a new one. If your wall thickness is at least from a 2x4 stud wall, you should have enough depth. Pay particular attention to the min/max when setting the new valve. Mock it up, as while the trim is guaranteed to fit if it's within that min/max, you may not like how it looks except when it's at a certain depth. The only other critical dimension is the distance from the valve body to the tub spout. Usually, that's not an issue, but it can be. If the valve is close to the spout, the larger cover may mean that has to move, too.

 

[Rancho]

Terry can tell you stories about finding all sorts of things IN the piping. You might have something like a pebble, or who knows what partially blocking the line that moves around. When it is sitting just so, it gives you problems.

The remodel plates are sized so that a competent plumber has enough room to cut out the existing valve and connect a new one. If your wall thickness is at least from a 2x4 stud wall, you should have enough depth. Pay particular attention to the min/max when setting the new valve. Mock it up, as while the trim is guaranteed to fit if it's within that min/max, you may not like how it looks except when it's at a certain depth. The only other critical dimension is the distance from the valve body to the tub spout. Usually, that's not an issue, but it can be. If the valve is close to the spout, the larger cover may mean that has to move, too.

If it were a pebble or other objects in the line, it would not affect just one faucet in one bathroom. It also would clear permanently and we would see the object come out.
It seems like it is some issue with the valve itself. As I mentioned, sometimes just moving the handle back and forth a few times after clearing the issue causes the issue to return before the plumber even leaves the premises.

Is there anyplace that lists physical dimensions of the Moentrol valves compared to the size of Positemp valves? How much larger are the Moentrol valves?

 

[Jadnashua]

If it were a pebble or other objects in the line, it would not affect just one faucet in one bathroom. It also would clear permanently and we would see the object come out.

Depending on the size/length/shape, not necessarily, as it could be in the line for that fixture. It might not make it around an elbow, so couldn't be flushed out. I'm not saying that's your problem, but saying that stranger things have happened. A valve cartridge typically lasts more than a decade, and when it starts to fail, usually leaks, not stops.

 

[Rancho]

Depending on the size/length/shape, not necessarily, as it could be in the line for that fixture. It might not make it around an elbow, so couldn't be flushed out. I'm not saying that's your problem, but saying that stranger things have happened. A valve cartridge typically lasts more than a decade, and when it starts to fail, usually leaks, not stops.

Another thing that seems to debunk something being in the line is the fact that the problem never happens in the middle of a shower. It always happens right when the shower is being turned on and the handle was just moved.
It happened again this morning. I turned the shower on to the hot side at full stream, then immediately heard a knock or “thud” sound and then the water pressure drastically dropped. Now, I have low pressure on the hot side again and the temperature is luke warm instead of hot. There is still full water pressure available when I turn the handle to the full cold side.

Does that description give any other ideas?