Moentrol - No water to shower

[Mike Starcher]

Hi,

Apologies if this has been asked. I couldn't find anything.

I have a Moentrol shower valve that supplies a shower head and four small body spray heads. One morning I suddenly have no water at all. I took off the faceplate and shut off the water using the two stop valves integral to the valve body. Pulled the main on/off cartridge out and turned the cold water back on. I got a short burst of water, then nothing at all. Turned the cold back off, then on again and got barely a trickle. Next, I tried turning the hot water on. Just a trickle. I took the balancing spool out and turned on the cold water and got a normal flow out of the spool socket. Same with the hot side. So I soaked the spool in vinegar and water for a couple of hours, even though it rattled and sounded and looked okay. I reinstalled the spool and again, barely a trickle out of either hot or cold. I removed the spool again and got a normal flow out of the spool socket. So, I called Moen and they sent a new spool and cartridge.

When the parts arrived, I put the new spool in but held off on installing the cartridge until I checked the water flow. I got more than just a trickle, but nowhere near the amount of water I should be getting. So now I'm stumped. I'm thinking that there must be a plugged port or orifice in the valve body itself where the water flows from the spool to the on/off/temperature control valve.

Any thoughts or ideas are definitely welcome.

 

[Terry]

If there is an issue with flow to one side of the faucet, the balancing spool will shut down the other side.
New spool, with both stops open, you may have something in the line on one side. Or perhaps the water heater is shut off, which amounts to the same thing.

I once found a valve with a small plastic ball in the 1/2" copper that was blocking the in line.

Again, in case this wasn't done. Both the hot and cold must be on at the same time for any water to flow. It will match whatever the worst case scenario is.

 

[Sponsor]

 

[Mike Starcher]

Okay, an update...

I did have hot and cold on at the same time and got just the trickle. After I wrote this post this morning, I went back in and started to tinker some more. I decided to pull the on/off cartridge and try to clean the socket out. The night before, I had reinstalled just the handle on the on/off valve when I was trying the water and I didn't take it back off. When I went back in this morning to pull the cartridge, I was a little frustrated and not really paying attention, so I pulled the diverter cartridge instead. Once I realized what I'd done, I pulled the on/off handle to turn on the water and it just gushed out of the diverter socket. :::scratching head:::

The cartridge didn't look bad but I soaked and cleaned it any way. I reinstalled it and everything worked. Go figure. there is obviously something about the way this contraption works that I totally do not understand. lol I was thinking that the diverter valve couldn't be the problem because it's downstream from the on/off valve. Right?? Who knows. lol

Anyway, I'm still not quite sure what was wrong but it works now.

Side note: I reassembled everything after making sure it didn't leak anywhere, turned it on and couldn't get any hot water. I turned the valve in the other direction and finally got hot water. It was backwards. :::grrrr:::

Took the handle off, turned the stem 180 degrees and put it back together, now it worked correctly. Adventures in plumbing. lol

If there is an issue with flow to one side of the faucet, the balancing spool will shut down the other side.
New spool, with both stops open, you may have something in the line on one side. Or perhaps the water heater is shut off, which amounts to the same thing.

I once found a valve with a small plastic ball in the 1/2" copper that was blocking the in line.

Again, in case this wasn't done. Both the hot and cold must be on at the same time for any water to flow. It will match whatever the worst case scenario is.

 

[Jadnashua]

The pressure balance spool valve is specifically designed to expect water pressure from both hot and cold at the same time. As Terry said, if only one supply is on, it will shut the other side off if it's working properly. The idea is, say something lowers the cold water pressure (someone flushes the toilet?), the supply of cold could drop leaving the hot still there, and potentially making a hot surge out of the shower. The pressure balance valve in this situation, shuts some of the hot down proportionally, so that the temperature on the outlet stays pretty much the same. The volume may go down as it starts to lower the available output, but since the valve can supply more volume than the shower head uses, you might not notice anything except you don't get scalded!

 

[Mike Starcher]

Thanks Jim!

Yep, I get that. I'm just not understanding how the diverter can play a part in that since it is downstream from everything else.

The pressure balance spool valve is specifically designed to expect water pressure from both hot and cold at the same time. As Terry said, if only one supply is on, it will shut the other side off if it's working properly. The idea is, say something lowers the cold water pressure (someone flushes the toilet?), the supply of cold could drop leaving the hot still there, and potentially making a hot surge out of the shower. The pressure balance valve in this situation, shuts some of the hot down proportionally, so that the temperature on the outlet stays pretty much the same. The volume may go down as it starts to lower the available output, but since the valve can supply more volume than the shower head uses, you might not notice anything except you don't get scalded!