Moen Posi-Temp,No water pressure on hot side in shower

PlumbingNewb · Sep 5, 2007

I have the handle that goes around in a full circle from cold to hot in my guest shower. When I turn it to cold I get normal cold water, but when I turn it all the way to hot it basically shuts off and nothing comes out.

I have a washer/dryer 2 stories below this room and it seems that in the guest bath under this room it sounds like water is constantly running in the pipes. I can't find any shutoff valves etc. so I don't know what to look for. All the other hot water is working in the kitchen, guest bath, and master bath.

Thanks for your help!!!!!!

Jadnashua · Sep 6, 2007

It helps to know the brand and model.

If it is a pressure balanced valve (required on all newer construction), then the spool may be stuck. Can't say if it can be cleaned up and would then work or if it needs to be replaced. There may be other things going on here.

Explain more about when and where you hear water running.

Sponsor · 2022-01-29T12:20:58-0800

BAPlumber · Sep 6, 2007

with all your fixtures off, check the water meter to see if it's moving. if so, there is a leak somewhere. you can also turn off the valve at the water heater and see if the sound stops. this probably won't solve the "no hot water issue" but will get us going.

PlumbingNewb · Sep 6, 2007

Thanks I'll try that. I don't think there is a leak though because my water bill is like $40 something a month and I take 2 showers a day so its not outrageous.

The shower handle on off looks like this:
I can't put a link so try this:
Moen Legend One Handle Chrome Shower Only Faucet

Model L3175
at home depot website

What should I do?

PlumbingNewb · Sep 7, 2007

If I remove the handle is there anything you suspect I can turn to open it up behind the wall like a valve or something?

PlumbingNewb · Sep 13, 2007

shamless bump... just need to know if I unscrew this thing if anything bad can happen and if I can actually get the valve open for hot water somehow even though I can't see one until maybe I open the thing up.

Markts30 · Sep 13, 2007

Shut off the water and take the valve apart...
see if you can get the spool inside loosened up - use some plumber's grease on it...
If the innards seem worn, take them to a good plumbing supply shop and get some replacements... Buy genuine Moen parts... no knockoffs

PlumbingNewb · Sep 16, 2007

ok I got the faucet off ok and behind the part you turn there are two little knobs you can turn with a flathead screwdriver. Should I mess with those? Maybe they are closed? There seemed to be a lot of drywall over one of these. I'm assuming they are hot and cold valves or something. What do I do??!!?!

Patrick88 · Sep 16, 2007

They are built in shut off's for the shower valve. I'm thinking that whom ever installed the shower valve did not set the high limit for the valve. If the high limit is set to high on delta valves when you turn it all the way on the pressure will drop almost like if you went to far and your starting to close it again.

I would adjust that and i think this will solve your problem.

PlumbingNewb · Sep 16, 2007

patrick88 said:
They are built in shut off's for the shower valve. I'm thinking that whom ever installed the shower valve did not set the high limit for the valve. If the high limit is set to high on delta valves when you turn it all the way on the pressure will drop almost like if you went to far and your starting to close it again.

I would adjust that and i think this will solve your problem.

Thanks, I turned the right one and it turned the cold water off. When I turn the shower handle to hot, nothing comes out even when I turn the one on the left which I assume is for the hot water. The sink and everywhere else gets hot water. Should I open up the valve on the left that must control the hot water and try to clean it? There is hardly any room to do anything in there without breaking the tile.

That water running like I said above is only once in a while, may be my neighbors or something also, not sure. Its a townhouse.

PlumbingNewb · Sep 16, 2007

Here is a pic of what I'm talking about, see attached

Patrick88 · Sep 16, 2007

It is a pressure balance valve. You should have no water coming out if you turn the water off on either side it is a safety feature.

just make sure the hot is open all the way or if you are thinking of opening the wall make sure the water is off all the way hot and cold

PlumbingNewb · Sep 16, 2007

patrick88 said:
It is a pressure balance valve. You should have no water coming out if you turn the water off on either side it is a safety feature.

just make sure the hot is open all the way or if you are thinking of opening the wall make sure the water is off all the way hot and cold

I put it in the open position and every other position while the water was turned on and nothing comes out... What is the next step to try? Thanks

Patrick88 · Sep 16, 2007

Do not open the valve unless you know the house main is off. On the new style single handle shower valves if you turn off one side and not the other the water will not come out no mater how much you turn the shower valve. It can fool you and is very dangerous. So to play it safe turn off the house main

All shut off valve are righty tighty lefty loosy.

PlumbingNewb · Sep 16, 2007

Thanks, I'll make sure to turn it off. When you say open the valve what am I doing and trying to accomplish? The middle piece?

Patrick88 · Sep 16, 2007

Sorry I just didn't want you to think that if no water is coming out it would be ok to open the valve as in take it apart.

PlumbingNewb · Sep 16, 2007

It doesn't look like there is really room for me to take much apart there without busting tile. What would a plumber check next to see what the problem is?

Patrick88 · Sep 16, 2007

The first thing is to make sure both hot and cold shut offs are on. The next thing to do is take the valve apart to see if something is blocking the flow. there really is not much to do about this unless you find that some valve (shut off) is not open all the way. Taking apart a shower valve can be very easy or very hard. Some valves can be fixed by replacing one piece some many pieces. Can you tell what brand the valve is. Sometimes the manufacture will send you new parts free.

PlumbingNewb · Sep 17, 2007

I'm not really sure where to go from here to take the valve apart. I'm sure you guys would know what to do... What should I try to do? Snap off that HC white piece of plastic or what? I have no idea what to do with this

Thanks!!

PlumbingNewb · Sep 17, 2007

I pulled that little U out of the top there, but I am having a lot of trouble getting that plastic part out of the middle.

Moen Posi-Temp,No water pressure on hot side in shower

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